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The Green Anole (Anolis carolinensis) has three stereotyped head bob displays (labeled A, B, and C) which it differentially uses during directed hetero- and consexual exchanges. We found free-ranging males advertise (i.e., nondirected signaling) with the same three displays in a complex but consistent manner. From videotapes of 10 adult males recorded across breeding and postbreeding seasons, we analyzed 2308 nondirected displays from two functional subsets of the advertisement context—”monitor” (stationary males signaling from monitoring sites) and “travel” (males signaling while moving between monitoring sites). Using five hypotheses to guide the analysis, we found breeding males (1) used all three display types during both monitor and travel; (2) averaged mostly C displays during monitor (ratio of C:A + B = 4:1); (3) increased A and B displays four-fold during travel (C:A + B = 1:1); (4) averaged a four-fold lower display rate during monitor than during travel (displays/min = 0.8 vs. 3.5, resp...

A longitudinal study (from neonate to adult) was made of the display behaviour of 36 fence lizards from 8 clutches. A frame-by-frame analysis of 941 video-taped displays revealed that the hatchlings possessed almost all of their adult display patterns by the first two days of life. Of the total variance in the display behaviour, ;’ % or less was attributed to experience. Of the variance among lizards, approximately half came from between clutches and half from between clutchmates. Our data indicate that the visual communication signals (head bob displays) of this vertebrate species are almost totally innate.

Aggressive encounters were staged between two species of Puerto Rican lizards (Anolis cooki and Anolis cristatellus) which share the same microhabitat (syntopic). The intensity of these interspecific matches was as great as their respective conspecific matches. When the two species interacted with either “look alike” congeners (A. cooki with A. monensis and A. cristatellus with A. gundlachi) or with the quite different appearing A. evermanni, aggressive intensity was only 1/6 that of the cooki-cristatellus encounters. It seems that A. cooki and A. cristatellus recognize each other as competitors; it was improbable that this interspecific aggression was caused by the two species misidentifying each other as conspecifics. Because A. cristatellus eventually dominated A. cooki during staged encounters, it is predicted A. cristatellus should ecologically displace A. cooki in their syntopic zones of contact.

Within a female-defence polygynous mating system, males of the lizard A. carolinensis use an array of stereotyped signals and aggressive tactics to acquire and defend long-term territories containing multiple, sedentary females. In competition, body size appears to be important because size of free-ranging males correlates positively with volume of male territories and number of patrolled females. Therefore, an ability to assess body size during territorial contests should be an adaptive attribute that would influence the tactics of intermale aggression. To examine this premise, we staged contests between 10 pairs of males matched for size (i.e. symmetric contests) and 10 pairs mismatched for size (i.e. asymmetric contests), while all 20 pairs of males were matched for habitat resources, a mate, and resident status. Overall, we found (1) contest profiles best fit the features of a ‘fixed-phase, sequential assessment’ model of game theory, (2) body size and mass were highly correlated with contest outcome, (3) none of 12 signal variables predicted contest outcome, and (4) paired males generally matched aggressive tactics and signalling behaviours. We also examined the asymmetric contest profiles for deviations from the profiles of symmetric contests. We tested the proposition that smaller males of size-mismatched contests would assess their disadvantage and choose a bluff strategy to mitigate risky behaviour and avoid fighting. We found, however, that the risk-mitigation hypotheses were unsupported. Smaller males were not playing a bluff strategy, but rather a hawk strategy. They initiated risky tactics by (1) invading the habitats of their larger opponents, an act that invited retaliation, (2) showing no tendency to stay away from larger opponents, (3) maintaining high levels of aggressive signalling as encounters intensified, and (4) engaging larger opponents in physical fighting, despite losing 90% of their encounters. These empirical results support a recent game theoretical construct (‘Napoleon complex’) that models size-asymmetric contests in which smaller males initiate fights that they usually lose. Our data suggest that, if smaller males of A. carolinensis have breeding territories, then they will engage in costly contests, despite a low probability of defeating larger and equally motivated opponents.

Summary We quantie ed the structure and use of signals exchanged by males and females within the female-defence polygyny of the lizard, Anolis carolinensis . During heterosexual interactions, both sexes performed three kinds of stereotypic headbob displays (A, B, and C) with equal precision. These three display types were essentially identical to A, B, and C display types previously documented for both sexes during consexual contests, and for males when displaying alone (non-directed context). Therefore, there is no courtship-specie c headbob display in A. carolinensis . Although interacting males and females displayed at a similar mean frequency (»20 displays/h), signalling was sexually dimorphic in that: (1) males used predominately C displays (89%), whereas females used predominantly A and B displays (48% and 50%, respectively); (2) males extended their dewlaps with almost every display (98%), whereas females extended their dewlaps with few displays (

Signal ontogeny was examined in green anoles (Anolis carolinensis). From 1,246 head bob displays given by 114 juveniles, it was found that juveniles possessed all 3 display types (A, B, and C) described for adults and that C displays were present at hatching, but A and B displays appeared to emerge gradually from a common precursor. Durations of the head bobs and pauses that make up juvenile displays tended to be more variable (i.e., less stereotyped) than those of adult displays. However, within the juvenile class, sex, age (or size), social context, and rearing environment (field or lab) had no effect on display structure or stereotypy. Thus, in contrast to typical signal ontogeny in songbirds and mammals, components of the green anole signal repertoire are expressed from early development. Similar to signal ontogeny in altricial species, maturation is nevertheless important for the complete and stereotyped expression of the adult signal repertoire.

I performed a displacement experiment with free-ranging adults of Anolis cristatellus, a tropical lizard species whose year-around space-use requirements are limited to small arboreal territories. Because A. cristatellus is a relatively sedentary species, selection for a generalized spatial orientation would seem unlikely. However, more than two-thirds of 25 lizards returned to home territories within an average of 3 d when relocated 11–62 m (equivalent to 2–26 territory diameters) to presumably unfamiliar release localities. Within the conditions of the study, there was no significant effect on returning success by displacement distance, sex, or body size. The returning performance of A. cristatellus supported two inferences. First, considering the costs and risks of traveling through unfamiliar habitat, returning to a specific location from a distant release point indicated the relative importance of a familiar home range to survival and reproduction by both sexes. Second, returning performance indicate...

Laboratory and field manipulations tested whether male Anolis carolinensis lizards and discriminate preference for novel females over resident females. In 16 laboratory trials, we videotaped social interactions between paired males and females during baseline session (male and resident female housed together 1–3 weeks), resident-female session (male and reintroduced resident female), and novel-female session (male and novel female with resident female removed). We examined 22 behavioural variables. Male behaviours did not differ significantly between baseline and resident-female sessions, nor did female behaviours differ significantly between baseline, resident-female and novel-female sessions. However, between resident-female and novel-female sessions, males significantly increased display rate (320%), volleys of repetitive displaying (300%) and volley length (150%), and significantly decreased the distance (375%) and number (430%) of movements travelled away from the female. We concluded that males discriminate novel females from resident females independently of female behavioural or chemical cues. In each of 18 field trials, we first videotaped baseline social interactions of the resident male and females in a naturally occurring, polygynous, breeding group. The next day, we released two novel females into the territory (so at least one female remained) and videotaped subsequent social interactions. In comparison to baseline observations, males significantly increased the proportion of time spent in female-directed activities (from 5% towards resident females to 53% towards the novel female) and the proportion of displays directed towards novel females (from 6% towards resident females to 51% towards the novel female), and significantly decreased the proportion of time spent in territorial activities (from 75% to 19%) and the proportion of displays used in territorial activities (from 94% to 44%). Data from both experiments indicate that males appear to distinguish among individual females, and use this ability to increase reproductive success by identifying and preferentially pursuing novel females over previously inseminated resident females. From the perspective of cognitive ethology, we suggest a model by which males control mating decisions within their territories.

Using the lizard Anolis carolinensis as its subject, an early and enduring model of psychobiology was presented in which neuroendocrines and social behavior interact to coordinate reproduction between the sexes. The adaptive context for the model was protandry, here defined as a "male-first" emergence pattern from winter dormancy to the onset of breeding. In the protandry scenario, males emerge, become reproductive, and contest for territories. Then, pre-reproductive females emerge to settle on male territories, whereby ovarian recrudescence is facilitated by the behavior of courting males. A collateral inference of the protandry sequence is that females are choosing their future mates from among local males and their territories (i.e., intersexual selection). The model and its assumptions, though never validated by field data, have served as the paradigm for many laboratory experiments on A. carolinensis. Recently, however, field studies described an intrasexually selected mating system for A. carolinensis, without evidence of direct female choice. Differences between the selective inferences from the two perspectives led us to test in the field a number of protandry-based characteristics previously ascribed to A. carolinensis. We monitored free-ranging adults across the winter-to-breeding period using data on sex ratios, social behavior, gut contents, sex steroids, and gonadal condition. We found no evidence of protandry, and little support for any of the associated assumptions. Instead, the sexes broadly overlapped in their temporal transition from winter retreats to an active status in the habitat, with average male reproductive development about 1–2 weeks in advance of females. We replace the traditional protandry-based A. carolinensis paradigm with a realistic onset sequence into the breeding season and a new model for the species' mating system. Our study underscores the need for field validation when laboratory-generated data are fitted to adaptive paradigms.

We documented the ontogeny of headbobbing display use in green anoles (Anolis carolinensis) by determining the effects of social context, sex, and body size on juvenile social interactions. Juveniles only gave displays in social interactions (never while isolated), and activity levels in general were much higher during interactions than during isolation. Neither social context (consexual or heterosexual) nor sex affected the type or quantity of displays and related behaviors (perch shifts, display modifiers, color changes, and approaches or retreats). Interactions always appeared to be aggressive in nature and qualitatively similar to interactions between adult females. Both males and females tended to increase overall activity during interactions with body size, including the use of displays and related behaviors, and large juvenile males performed more headbobbing displays than did large juvenile females. These results suggest that juvenile social interactions are agonistic in nature and that they function to defend both immediate and future resources (prospective resource hypothesis). It is likely that resource protection confers the immediate benefits of suitable habitat for foraging, thermoregulation, and predator avoidance, and it is hypothesized that the primary future benefit is the acquisition of the eventual breeding territory that juveniles will hold as adults.

Unlike many polygynous species, we found that females of the lizard, Anolis carolinensis, have the same repertoire of aggressive signals as males. These shared signals included three stereotyped headbob display patterns (types A, B, and C) that were performed with no significant intersexual difference in amplitude displacement. However, we did find the following sexual dimorphisms in signal structure and use. Females (1) had a smaller average extendable throat fan (i.e., dewlap) area (0.22 cm2 ) than males (1.52 cm 2 ), (2) never displayed when alone (0/h), whereas males frequently did (18/h), (3) displayed 10-fold less during consexual encounters (17/h) than males (168/h), (4) lacked the ritualized intermale combat scheme of circling, jaw-sparring, and jaw-locking, (5) infrequently used physical contact in consexual encounters, whereas males frequently did, and (6) did not employ a shifting use of signals with decreasing interfemale approach distance, whereas contesting males did by decreasing the frequency of C displays in favor of A and B displays, decreasing the use of the dewlap during displays, and decreasing the sequencing of displays in volleys. These results are in accord with field studies, which report limited interfemale territoriality (i.e., low consexual threat) and short display broadcast distances, whereas male territorial behavior is well developed (i.e., high consexual threat), with frequent long-distance displaying between consexuals. We suggest that these displays, which function in competitive interference, have been less directionally selected in females than in males because the outcomes of consexual contests carry fewer reproductive consequences for females than for males.

1. We used continuous 8-day monitoring to document the spatial and mating relationships of free-ranging Anolis carolinensis lizards at each of seven habitat-delineated study sites. 2. We found a polygynous social structure, consisting of a male and 2-6 resident females (x = 3.3), on each site. 3. Spatially, both sexes utilized all available perch heights and diameters on the study sites (habitat generalists), though females tended to perch slightly higher and on significantly thinner substrata (x = 2.4 m, 3.4 em, respectively) than males (x = 2.3 m, 5.3 em, respectively). 4. Mean home range volume was eight fold greater for males (69 m3) than females (8 m3). Male home ranges were exclusive of other males (0% overlap), while neighboring female home range volumes overlapped an average of 18%. 5. Male snout-vent length (SVL) was positively correlated with male home range size (area, volume) and with number of resident females, but not with resident female SVL or resident female home range size. 6. Half of 397 male-female encounters led to close contacts in which males influenced courtship outcomes by: recognizing receptive and non-receptive females (differential display rate); bypassing 69% (85/123) of mating opportunities with receptive females; and copulating only when courtship was male-initiated. 7. Larger males (who also had larger territories and more females) courted less per female, but with longer duration, and had longer copulatory durations than smaller males. 8. Male frequency of copulation (x = once/1.4 days), however, had no correlates with measured variables; females were mated without bias to male or female attributes. 9. Male potential reproductive rate (PRR), estimated from the number of copulations with different females, positively correlated with male SVL. Female PRR, estimated from the inter-mating interval (i.e. the single-egg clutch interval), did not correlate with any measured male or female trait. 10. Our data, in concert with other field studies and A. carolinensis life history traits, document a polygynous mating system in which females seem to fit a 'no cost, neutral-mate-choice' model, and males (in response to sedentary, contiguously distributed females who clutch at weekly intervals over a 4-month period) employ territorial contests within an endurance rivalry as a prime mechanism for mate assortment.

1. The activity profile of free-ranging individuals should reflect how females and males are optimizing their respective reproductive efforts. By using the polygynous, sexually dimorphic lizard, Anolis carolinensis, we expected to find an example of pronounced intersexual asymmetry in daily activity patterns. 2. In contrast to males who should focus on blocking consexual access to resident females, we expected females to strategically facilitate egg production by minimizing conspicuous and unnecessary behavior, while feeding frequently from a defended food resource optimal to their needs. 3. During a 56 day period, we made a 90 h record of focal animal observations on 22 unmanipulated, reproductive females; then we compared this activity profile to a known profile for males. We found the following. 4. Females were 1.6 times more stationary (82% of day), moved 1/7th the distance (< 40 m/day), displayed at 1/8th the overall rate (< 14 displays/h), and used < 1/35th the number of displays in non-directed advertisement (1.6 displays/h) as males. 5. Females spent 1/30th the time (0.3% of day) in overt defense of territories 1/9th the volume (8 m3) as males. 6. However, both females and males had equivalent feeding rates (1.2 times/h), suggesting that the energetic needs of female egg production and male territorial maintenance are comparable. 7. The small, lightly defended territories and low feeding rates of females (along with their reptilian metabolism and insectivorous diet) indicate that females have a wide latitude in which to meet their energetic costs. 8. As expected, the proportion of intersexual contacts was similar between female and male profiles. Courtship and copulations occupied 3.2% and 3.9% of the females' day, respectively, with copula averaging 26 min in duration. 9. In a female activity profile which de-emphasized conspicuousness, we found little evidence for a pheromone-based alternative to visual signalling. 10. Predation, as an immediate threat to lizard activities, was not seen during three months of observations. We noted only four instances of avoidance behavior.

Abstract. Anolis carolinensis was found to have three stereotyped and distinct headbob patterns, referred to as types A, B and C. Each type had two variants, one in which the dewlap appeared mid-display, and a second in which dewlap extension was absent. Display types A, B and C comprised all of the headbob signalling during two contexts: (1) the advertisement context, when males were isolated (male-alone); and (2) the aggressive context, when each male was paired (male-male) during territorial contests. During the advertisement context, the mean display rate was 0·3/min; half of the displays were performed singly, the rest in bursts (volleys) of two to six displays/volley. Dewlap extension accompanied 97% of the displays, and all three types of displays were used with similar frequency. During the male-male context, mean display rate varied inversely with inter-male separation distance, being 1·4, 2·0 and 3·8/min at distances greater than 100 cm, within 20-100 cm and less than 20 cm, respectively. At large inter-male separation distances (> 60 cm), long volleys (containing four to nine displays) were common, type C displays predominated, and dewlap extension accompanied 92% of the displays. At short inter-male separation distances ( A. carolinensis headbob display behaviour. Recommendations are made for the abandonment of functional labels on patterns of display behaviour (e.g. assertion display and challenge display), regardless of taxon studied.

This study addressed the role of testosterone (T) in the development of sexually dimorphic behavior in the green anole lizard, Anolis carolinensis. We documented the pattern of endogenous T concentrations during ontogeny and we determined the behavioral effects of experimentally elevated T in juvenile males and females. T concentrations were measured in the plasma of hatchlings from eggs incubated in the laboratory, in juveniles of all sizes sampled in the field, and in the yolks of freshly laid eggs in the laboratory and were compared to plasma T in adult females (measured in this study) and adult males. There were no sex differences in plasma T in hatchling and small juvenile (26-mm snout-vent length, SVL;14 days old) males and females, concentrations of which in both sexes tended to decline over the 14-day posthatching period. Plasma T sharply increased in juvenile males, but not females, after approximately 14 days posthatching (25-mm SVL), and it became significantly higher after approximately 38 days posthatching (30-mm SVL). Plasma T for juvenile males was within the range detected in breeding adult females, but it was 20- to 45-fold lower than that of adult males, breeding or postbreeding. All eggs contained detectable yolk T, but eggs that gave rise to males contained nearly twice as much yolk T as those that gave rise to females. We do not know whether this yolk T comes from the mother, embryo, or both. In behavior trials conducted in the laboratory, juveniles (36- to 42-mm SVL) with T implants, regardless of whether they were male or female, had increased activity levels compared to juveniles with blank implants, due to increased rates of nearly every behavior monitored. These results are discussed in the context of the organization-activation theory of sexual differentiation and the particular life history of A. carolinensis.

1. Anolis carolinensis, the most northerly distributed member of its neotropical genus, does not hibernate, but facultatively basks during days with direct sunlight throughout the December to March period. 2. Both sexes were primarily inactive (92% of emerged time), infrequently foraging (6.4%), interacting socially (1.3%), or responding to predator threats (

The behavior of 10 free-ranging male Anolis carolinensis was videotaped in a riparian habitat for 41 h during May-July of the breeding season; 8 of the original 10 males plus 1 substitute were videotaped for an additional 22 h during August-September of the post-breeding season. Comparisons of breeding versus non-breeding seasons showed dramatic shifts in the per- centage of time spent in the following behavioral modes: (1) "stationary," 51.1% versus 85.6% (with respective display rates of 46/h versus 2/h); (2) "travel," 26.7% versus 2.6% (with respective distance rates of 73 m/h versus 106 m/h and display rates of 209/h versus 78/h); (3) "creep,"

A montane population (elev. 690 m) of the Jamaican lizard, Anolis opalinus, was monitored weekly for 12 months. A greater percentage of reproductive individuals was found year-round than in any previously described anole from a similar latitude and elevation. The high level of annual reproduction occurred in spite of distinct wet-dry periods (171 cm of rain, May-Oct.; and 32 cm of rain, Nov.-April). All males (n = 146) from all months were fully gametogenic. Morphometrics of sexual structures, however, reflected some monthly variance. Mean monthly testis weight showed a 2.2-fold annual range; other measured sex structures fluctuated much less (0.3-0.6-fold). As a group, measured variables reached their maxima during April-July and minima during Oct.-Nov. The testicular cycle was shifted two months in advance of the wet season, with almost no male reproductive structures correlated with the annual cycle of climatic variables. Males showed no tendency to lose weight during their peak reproductive months. Field observations recorded copulations, advertisement displaying, and territorial defense the year-round. For all females (n = 173), the proportion gravid in monthly samples varied from 42% in Dec. to 100% in Aug. Though apparently not initiated by the onset of rain in May, reproductive variables combined to reach their maxima (JuneOct.) during warm wet months. Occurrence of females carrying two oviductal eggs began in April and ceased in Oct.; total oviductal egg volume overlapped the seven months of highest maximum daily temperatures (April-Oct.) and the six months of greatest rainfall (May-Oct.). Large oviductal egg size was associated with large females, but larger females did not appear to produce more eggs than smaller females in either the wet or dry periods. Female reproductive variables reached their greatest levels several months after the male cycle had registered its maxima; no reproductive variables significantly covaried between the sexes.

Male Chamaelinorops barbouri were videotaped in the lab within male-alone and male- male contexts. Subjects exhibited two types of headbobs, Simple Nods and Dewlap Displays. Simple Nods occurred in both contexts, and were "minimalist" bobs, consisting of a single low amplitude nod, no dewlap extension, and short duration (i = 0.6 sec). Three-fourths of 959 Simple Nods were immediately associated with head or eye shifts, perhaps facilitating depth perception (displacement parallax). There was no evidence for a signal function. Dewlap Displays only appeared in the male-male context, and consisted of slow, large-amplitude headrocking with a continuously extended dewlap. Display features were highly variable; duration ranged from 2-92 sec (N = 130), while non-stereotyped headrocks ranged 1-7/display. The Dewlap Display functioned as a signal, but it lacked the stereotypy typical of Anolis displays. The Dewlap Display was structured like the non-stereotyped headrocking/dewlapping behavior which many Anolis perform alone or as optional introductions to their species-specific displays. Unlike Anolis, C barbouri showed little or no territorial behavior and no male-alone advertisement displaying. With one exception, no postural modifiers to enhance lateral profile were exhibited, and lateral presentation, the body orientation preparatory to signalling a recipient male, was imprecise or absent. Both lateral enhancement and presentation are basic intimidation components in Anolis contests. Male- male approach behavior by C. barbouri lacked circling, mouth gaping, jaw sparring, or jaw locking, all

Based on my conceptual framework of anoline display behavior, I am suggesting the following evolutionary trends. Lateral presentation during display was probably promoted by monocular vision. Along with lateral presentation, postures evolved to increase lateral outline. These postures which magnified body size were probably of selective advantage within aggressive social contexts since larger animals tend to dominate smaller ones through bluff. Body movement evolved along with lateral orientation and size-enhancing postures. These movements would be most effective if they complemented lateral orientation. Effectors available for such movements were primarily pre-adapted for vertical motion. The patterns of movement generated were probably simple oscillatory bobbing movements by the head which were weakly stereotyped, interspecifically similar, appearing in many contexts, and having a weakly defined information content. Events having selective advantage for species recognition promoted stereotypy of bobbing behavior into species-unique displays; each species had its unique signature display which served in a manifold communicatory capacity. The signature display appeared in assertion, courtship, and challenge contexts. Its information content varied depending upon context and recipient of the display (e.g., male or female). Besides the stereotyped aspects of the display, certain features remained variable with potential information significance. Core variability (see text) promotes individual recognition and may be the origin of new unique display patterns as sibling species emerge. Display modifiers (see text) are variable display features shared by members of a population (many being shared interspecifically) that provide a graded appearance to display performance; modifiers can indicate level of arousal and facilitate interspecific communication. For some species display repertoire size seems to have evolved from a single display (signature display) to repertoires of multiple displays; these subsequent displays are generally restricted to aggressive interactions.

The curly-tailed lizard is a ground-dwelling, territorial species, whose home range areas were stable and averaged 79 m 2 (males), 43 m 2 (females) and 6 m 2 (juveniles). Every male had one to three females within his home range. The average home range overlap varied within and between age and sex classes, from 8% of male home range areas overlapping with juvenile home ranges to 100% of juvenile home ranges coinciding within male home ranges. Except for three, each of the 24 juveniles on the study area was exclusively associated with an adult male and female whose territorial behaviour prevented access of other adults to the juvenile. This was significant because 36% of the tested resident adults (three males, six females) attacked tethered conspecific juveniles and were considered cannibals. All 24 resident juvenile home ranges were within non-cannibal adult home ranges. Only three juveniles were at risk by having their home ranges also overlapped by a cannabalistic adult. No adult-free refugium existed for juveniles as their separation distances from non-cannibalistic adult. averaged 1·0 m (cannibals had no juveniles nearby). Our data indicate that: (1) exploitative infanticide may be a prime source of juvenile mortality; (2) stable, coinciding territories of a non-cannibalistic adult male and female provide associated juveniles with protection against cannibal adult interlopers; and (3) 88% of resident juveniles were being protected from possible cannibalism by only 30% of the adults on the study area.

Anolis opalinus lacks even one discrete display pattern. Syntopic with as many as four congeners, A. opalinus contradicts the hypothesis that increased stereotypy of species-recognition displays is favoured among sympatric congeners. Head bobs (4 to 11) and dewlap pulses (0 to 8) varied per display. However, a re-occurring ‘theme’ was isolated which explained the variable bob cadences of most displays (75%). This theme was: (1) an initial double head bob series, (2) a middle bob series of successively quickening cadence, and (3) a final bob series of successively slowing cadence. Sixteen display-related parameters were examined for intra-display correlations; all but a few correlations were non-significant. The unusual opalinus display behaviour may have resulted from relaxed selection for stereotyped displays, with other features being used for mate selection and species recognition.

Visitor behavior was evaluated in the National Zoo's reptile house. Nearly 600 visitors were tracked; time spent in the house and time spent looking at exhibits were noted. These parameters were investigated by sex, age, and type of visitor grouping. The most looked-at exhibits were determined. For 573 visitors, the mean time in the reptile house was 14.7 minutes. Only about 8 minutes was spent looking at exhibits, and this time was strikingly similar for age, sex, and group type. Time spent looking at exhibits was negatively correlated with visitor density. Amphibians and lizards were looked at for less time than snakes and turtles. Crocodilians were looked at longer than the other taxonomic groups, while larger animals in all groups were looked at longer than smaller ones. This study and other similar studies imply that the public does not respond to exhibits with the expected interest and enthusiasm. It is hoped that with a better understanding of the public through research, zoo staff can improve visitor interest in the exhibits.

[Analysis of 316 filmed type A (signature) displays from 22 male Anolis limifrons showed that some display aspects were quite stereotyped, while other features demonstrated significant intraindividual variability. 1) Dewlap extension accompanied a basic seven head bob signature display; the head bobbing pattern incorporated a one long-three short-one long cadence which was a strongly stereotyped characteristic of the signature display. 2) Range of mean display durations for the sampled lizards' basic display (first seven head bobs) was relatively narrow, being 2.08 sec for the fastest performer and 3.20 see for the slowest; the population mean and its standard error was 2.73 ± 0.03 sec with a coefficient of variability (standard deviation/mean X 100) of 19.5%. 3) The display duration, however, showed much intraindividual variability; of the partitioned temporal variance, 64% was attributed to the within lizard component and 36% was contributed by the between lizards component. 4) Lizards performed displays in succession, usually in volleys of three displays at a time. 5) Positional effect (whether an A display was performed singly or first, second, or third in a volley) was correlated with intraindividual variability of display duration (initial displays were shortest), total number of head bobs in a display (initial displays had more bobs), and appearance of certain optional introductory movements (initial displays more frequently incorporated introductory movements). 6) Increasing number of display head bobs in the A display was also correlated with appearance of optional modifiers., Analysis of 316 filmed type A (signature) displays from 22 male Anolis limifrons showed that some display aspects were quite stereotyped, while other features demonstrated significant intraindividual variability. 1) Dewlap extension accompanied a basic seven head bob signature display; the head bobbing pattern incorporated a one long-three short-one long cadence which was a strongly stereotyped characteristic of the signature display. 2) Range of mean display durations for the sampled lizards' basic display (first seven head bobs) was relatively narrow, being 2.08 sec for the fastest performer and 3.20 see for the slowest; the population mean and its standard error was 2.73 ± 0.03 sec with a coefficient of variability (standard deviation/mean X 100) of 19.5%. 3) The display duration, however, showed much intraindividual variability; of the partitioned temporal variance, 64% was attributed to the within lizard component and 36% was contributed by the between lizards component. 4) Lizards performed displays in succession, usually in volleys of three displays at a time. 5) Positional effect (whether an A display was performed singly or first, second, or third in a volley) was correlated with intraindividual variability of display duration (initial displays were shortest), total number of head bobs in a display (initial displays had more bobs), and appearance of certain optional introductory movements (initial displays more frequently incorporated introductory movements). 6) Increasing number of display head bobs in the A display was also correlated with appearance of optional modifiers.]

[Analysis of 666 filmed displays of 23 male Anolis limifrons from Panama revealed: 1) The species has an agonistic repertoire of five head bob patterns (A-E) and one dewlap display. 2) During male-male interactions, the decrease in intermale distance correlates with a progression of display usage from A → B → C → D → E. 3) When lizards exchanged displays within a short time span (1 min), the answering animal usually performed a display type of the same or the next type up in the A → E series, almost never was the answering type further down in the A → E series. 4) The D display is the most elaborate pattern and the E type the least; the E display occurred during face off orientations between combatants when they were within leaping distance of each other. 5) There was a trend for display modifiers to appear with greater frequency with the progression of display types from A to E. 6) Displays were frequently performed in volleys of two to four displays at a time, usually being three to a volley. 7) The first display of a volley was always of "higher" type in the display series A → E than the subsequent display of a volley i.e., B, A, A ; C, B, A ; D, A, A) ; if all the displays of a volley were of the same type, the first contained more modifiers than the others (e.g., introductory movements, more head bobs). 8) Presumably, the stepwise progression of display types from A to E during agonistic encounters reflects increase in motivational state., Analysis of 666 filmed displays of 23 male Anolis limifrons from Panama revealed: 1) The species has an agonistic repertoire of five head bob patterns (A-E) and one dewlap display. 2) During male-male interactions, the decrease in intermale distance correlates with a progression of display usage from A → B → C → D → E. 3) When lizards exchanged displays within a short time span (1 min), the answering animal usually performed a display type of the same or the next type up in the A → E series, almost never was the answering type further down in the A → E series. 4) The D display is the most elaborate pattern and the E type the least; the E display occurred during face off orientations between combatants when they were within leaping distance of each other. 5) There was a trend for display modifiers to appear with greater frequency with the progression of display types from A to E. 6) Displays were frequently performed in volleys of two to four displays at a time, usually being three to a volley. 7) The first display of a volley was always of "higher" type in the display series A → E than the subsequent display of a volley i.e., B, A, A ; C, B, A ; D, A, A) ; if all the displays of a volley were of the same type, the first contained more modifiers than the others (e.g., introductory movements, more head bobs). 8) Presumably, the stepwise progression of display types from A to E during agonistic encounters reflects increase in motivational state.]

Sceloporus undulatus hyacinthinus display behaviour was studied in the field and laboratory. Four major conclusions emerged. First, ‘jiggling’ seems to be a generalized behaviour appearing in many contexts with no apparent specialized function. Second, there are two distinct display types (A and B) in the species' repertoire besides jiggling. Third, based on 177 video-taped displays by 11 males, each of the two display types was extremely stereotyped. Last, the stereotypy is of two kinds. For the A displays, all males performed a display pattern common to the population (intra-population stereotypy); this would structure the behaviour for a species recognition function. For the B display, each male performed a consistent pattern. However, each male's B displays were to a lesser or greater extent individually unique (intra-individual stereotypy); this would facilitate individual recognition. Some males' B displays showed sufficient pattern variation to make it impossible to present a single display pattern representing the type B pattern for the population.

The Jamaican Anolis opalinus has different perch height characteristics depending on locality. Toward the center of the island, around Mandeville, A. opalinus characteristically perches low, being classified as a trunk—ground species. In Kingston, however, A. opalinus perches high, classified as a trunk—crown species, Evidence indicates the Kingston A. opalinus would also perch low except that interaction with Anolis I. Lineatophus forces A. opalinus into perch sites higher than appear to be the species' preference.

The maximum critical flicker-fusion frequency (CFF) was determined for seven species of anoline lizards. The congeners showed a wide range of CFF values from 26 to 42. These values correlated with the general level of insolation in each species' microhabitat such that the brighter the habitat, the higher the CFF.

STAMPS, J. A. 1973. Displays and social organization in female Anolis aeneus. Copeia 1973:264-272. TALBOT, J. J. 1976. Ecological and behavioral factors regulating the spatial distribution of Norops humilis and N. limifrons (Sauria: Iguanidae) at a tropical EXTON, O. J., J. BAUMAN AND E. ORTLIEB. 1972. easonal food habits of Anolis limifron . Ecology rainforest locality. Unpubl. Ph.D. dissertation, Univ. S uthern California, Los Angeles. .1977. Habitat selection in two tropical anoline lizards. Herpetologica 33:114-123. WILSON, E. 0. 1975. Sociobiology. Belknap Press.

Audition in Anolis grahami was investigated using classical conditioning of subjects within a simulated "natural" habitat. The conditioned stimulus (CS) was a tone which matched the dominant frequency of the species' agonistic type A vocalization; shoving a subject from its perch with a rod was the aversive unconditioned stimulus (UCS). Before conditioning experiments took place, baseline observations showed no observable responses by the lizards to the tone. Furthermore, during the conditioning experiments, evidence of learning (i.e., orienting and avoidance behavior during presentation of the tone) was more evident when visual cues were reduced. These results indicate that the species will respond to sounds, but that it has a greater reliance on visual rather than auditory information.

An adult male hybrid resulting from a cross between Anolis grahami and Anolis lineatopus neckeri was discovered in Mandeville, Jamaica. Twenty-two diagnostic characters which differentiate the parental species were used to confirm and examine the results of hybridization. These included scalation, body proportion, body color, non-display behavior, display behavior and biochemical characters. Though many of the hybrid's features were intermediate to parental characteristics, some strongly reflected the characteristics of just one parent. This was particularly true of the behavior in which the hybrid was quite grahami-like. However, when placed in social situations with a male of one or the other parental species, there was none of the agonistic behavior usually associated with male-male intraspecific interactions; the hybrid did not react as if it were a member of either parental species. Also included are the first descriptions of the signature displays for A. grahami and A. 1. neckeri.

Seasonal difference in the rate of growth of lizards has generally been attributed to changes in food availability (Stamps, 1977; Dunham, 1978; Andrews, 1979, 1982). Recently, however, Stamps and Tanaka (1981) provide evidence that water may limit growth of Anolis aeneus at Grenada independently of the effects of food (insect) availability. Here we report the possible limiting effects of water on the growth of another West Indian lizard, Anolis opalinus, during the dry season.

The Hispaniolan lizard, Lezocephalus schreibersi, precisely maintained a narrow range of body temperatures (Tb) (R = 36.7, SE = 0.17 C) that was significantly above concomitant air (Ta) and site (Ts) temperatures throughout all but the last hour of their emergence period. Lizards moved frequently between shade and sun throughout the day. Hourly basking frequency of the population was greatest (80%) when most lizards were emerging from their burrows (0900-0959 h), gradually declined to 35% at midday, then oscillated between 20-40% for the remaining afternoon hours. An hour before the majority of lizards entered their borrows (1700 h), movement markedly decreased and Tb declined to overlap Ts, as lizards appeared to relax thermoregulatory behavior. An important feature of this species' thermoecology is that the elevated and relatively stable Tb of Leiocephalus schreabersi permitted the lizards to be physically active during the entire day; rising ambient temperatures during the day never reached the maintained Tb Of this stenothermic species. In addition, no seasonal effects (November vs. May-June) were detected in the above thermal profile.

MILLER, R. R. 1961. Man and the changing fish fauna of the American Southwest. Pap. Mich. Acad. Sci. 46:365404. ,AND J. E. DEACON. 1973. New localities of the rare warm spring pupfish, Cyprinodon nevadensis pectoralis, from Ash Meadows, Nevada. Copeia 1973:137-139. , AND R. MILLER. 1942. Rearing desert fish in garden pools. Aquarists J. 15:96-97. MINCKLEY, C. O., AND J. E. DEACON. 1973. Observations on the reproductive cycle of Cyprinodon diabolis. Copeia 1973:610-613. MINCKLEY, W. L., AND E. T. ARNOLD. 1969. "Pit digging", a behavioral adaptation in pupfishes (Genus Cyprinodon). J. Ariz. Acad. Sci. 5:254-257. , AND M. ITZKOWITZ. 1967. Ecology and effects of intestinal gas accumulations in a pupfish (genus Cyprinodon). Trans. Amer. Fish. Soc. 96: 216-218. NAIMAN, R. J., S. D. GERKING AND T. D. RATCLIFF. 1973. Thermal environment of a Death Valley pupfish. Copeia 1973:366-369. OTTO, R. G., AND S. D. GERKING. 1973. Heat tolerance of a Death Valley pupfish. (Genus: Cyprinodon). Physiol. Zool. 46:4349. PETERS, H. M. 1941. Fortpflanzungsbiologische und Tiersoziologische Studien an Fischen. 1. Hemichromis bimaculatus Lacepede in Florida. Gil. Z. Morphol. Okol. Tiere. 37:387-485. PISTER, E. P. 1974. Desert fishes and their habitat. Trans. Amer. Fish. Soc. 103:531-540. RABE, J. R., A. A. ECHELLE AND H. E. SCHLICHTING. 1973. Viability of algae in the digestive tracts of two cyprinodonts. Prog. Fish-Cult. 35:147-149. RANEY, E. C., R. H. BACKUS, R. W. CRAWFORD AND C. R. ROBINS. 1953. Reproductive behavior in Cyprinodon variegatus Lacepede, in Florida. Zoologica, N. Y. 38:97-104. ROBERTS, J. L. 1961. The influence of photoperiodism upon thermal acclimation by the crucian carp, Carassius carassius (Lacepede). Zool. Anzieger 24 (supp.): 72-78. . 1964. Metabolic responses of freshwater sunfish to seasonal photoperiods and temperatures. Helgol. Wiss. Meersunters. 9:459-473. STEVENSON, M. M., AND T. M. BUCHANAN. 1973. An analysis of hybridization between the cyprinodont fishes Cyprinodon variegatus and C. elegans. Copeia 1973:682-692. TEXAS ORGANIZATION FOR ENDANGERED SPECIES. 1975.

A new cluster census method was used to examine the intra- and interspecific micro-dis- tributions of two syntopic lizards, Anolis cybotes and Anolis caudalis, across seasons (November, June). Numbers of A. caudalis were very stable across seasons; males slightly outnumbered females (1.2 sex ratio). In contrast A. cybotes had a 1:1 sex ratio in November, then numbers of male A. cybotes dramatically declined by June, resulting in a 2:3 ratio. We speculate that this was related to pronounced territorial behavior. Female A. cybotes were more closely associated with males in June (breeding season) than in November, resulting in multiple females per male in the breeding season. There was some partitioning of the structural habitat by species and sex classes which, for the most part, was stable between seasons. In general, the smaller A. caudalis preferred high perches (>2 m) on large trees, while A. cybotes perched under 2 m. Male A. cybotes also had a preference for large trees. Female A. cybotes, on the other hand, used all available vegetative structures without preference, and tended to perch below conspecific males (C = 1 m). Quantification of habitat partitioning, however, indicated much overlap among species-sex classes. Most habitat overlap coefficients were high (.90-.99). Discriminant analysis produced few significant differences between lizard classes, with poor discrimi- nation of niche uniqueness. Anolis cybotes males had the least discrete habitat niche (10% discrimination). The expectation of male A. cybotes (large and aggressive) dominating the smaller A. caudalis did not materialize. Data did not indicate any obvious interspecific competition as niche overlap values did not vary much with season and population density. In June when male A. cybotes are territorial, the habitat niches of other classes of lizards did not change significantly from November values, or they shifted toward that of A. cybotes.

A stomach analysis of 340 lizards collected in 33 samples over a 12 month period showed that Anolis opalinus eats arthropods, primarily ants by number (70%). By volume, however, ants comprised only 12% of the food bulk, with lepidopteran larvae and orthopterans being the main food items (46%). The lizards fed predominantly on soft bodied prey, except for ants. We found almost no evidence for food niche partitioning in the size dimorphic A. opalinus. All age and sex classes of lizards had eaten similar sized prey and prey taxa. When a significant difference was detected among classes, it was frequently the smaller lizards which had eaten the larger prey. In fact, season had more effect on diversifying the diet than did size of the lizards' trophic structures (i.e., mouths) or any possible feeding preferences. Niche overlap indices for prey length (0.86-0.94) and prey taxa (0.82-0.93) among all age-sex classes ran higher than those reported for a mainland anole with almost no sexual size dimorphism. Comparison of variables between the seasons (dry-Nov.-Mar., wet-AprilOct.) showed that lizards tended to ingest about the same volume of food (approx. 17 mm3 of food/g of lizard body wt). However, lizards ate more, but smaller prey in the dry season and fewer, but larger prey in the wet season. Relative fat body and liver weights were highest in the dry season and lowest in the wet season. Adult males and especially adult females experienced the greatest weight loss in these energy reserve organs; this was attributed in part to breeding activities. Coefficient of condition calculations (body wt/SVL) showed no body weight loss between seasons for any age-sex class of lizards. For the population, the volume of food taken across seasons appeared sufficient to increase energy reserves during the dry season and maintain body weight during the wet season.

The stereotyped head bob displays of three Anolis sibling species, formerly recog- nized only as A. brevirostris, were quantitatively analyzed from 736 filmed displays by 46 subjects. The three species are sequentially distributed along the west coast of Haiti, with A. websteri in the north, A. caudalis in the middle, and A. brevirostris in the south. It has been hypothesized that a behavioral isolating mechanism, such as the head bob displays, was serving to separate the species. Our data support this possibility. Each species' behavioral repertoire contained two categories of homologous and species-unique displays: the Type A and B displays. A single Type A display pattern was found in each repertoire, and it served as the species' signature display. The Type B displays were more complex than the A displays, and in A. brevirostris and A. websteri were represented by two and three different vari- ations, respectively. Each species' A display resembled that of its siblings; however, discriminant analysis procedure clearly discriminated between the three A display patterns. Likewise, the B display patterns of the combined sibling repertoires were also clearly separated by the discriminant analysis procedure, confirming their species uniqueness. Interspecific comparisons showed the larg- est differences in homologous displays to occur among geographically adjacent species, especially between the displays of A. websteri and A. caudalis. Character displacement may have enhanced these differences.

VITT, L. J. 1981. Lizard reproduction: habitat specificity and constraints on relative clutch mass. Amer. Natur. 217:506-514. -, AND T. E. LACHER, JR. 1981. Behavior, reproduction, habitat and diet of the iguanid lizard Polychrus acutirostris in the caatinga of northeastern Brazil. Herpetologica 37:53-63. , R. C. VAN LOBEN SELS AND R. D. OHMART. 1978. Lizard reproduction: annual variation and environmental correlates in the iguanid lizard Urosaurus graciosus. Herpetologica 34:241-253. SAVANNAH RIVER ECOLOGY LABORATORY, DRAWER E, AIKEN, SOUTH CAROLINA 29801 AND BIOLOGY DEPARTMENT, WHITTIER COLLEGE, WHITTIER, CALIFORNIA 90608. CURRENT ADDRESS (LJV): BIOLOGY DEPARTMENT, UNIVERSITY OF CALIFORNIA, Los ANGELES, CALIFORNIA 90024.

A statistical analysis of variation in the assertion display of Anolis nebulosus was computed from 599 filmed displays of 59 males. A populationtypical assertion display was shared by all examined lizards. Each lizard performed his display-action-pattern with remarkable consistency. The duration of the display's artificially divided units as well as its total sequence, however, showed large variation between individual lizards. No difference in the display pattern appeared when males were compared with females, when lab-held animals were compared with field-filmed individuals, or when lab-held animals were re-examined after a year in captivity. However, display pattern differences did appear when lizards from Nayarit were compared with those from Colima, Mexico. Display analysis can be a useful taxonomic tool for subspecies and species characterization.

A consecutive 12-month food-habits study was made of 475 green frogs, Rana clamitans, in southern Illinois. The greatest volume of food was consumed during the spring, months, whereas least food was ingested in the winter. During winter juveniles were more active food gatherers than adult frogs. Juvenile frogs ingested only half the average volume of food during the year as did adults. Adult females consumed a much greater volume of food than adult males during the breeding season. Immature and aquatic organisms composed 31 and 32%, respectively, of the total volume of animals consumed. In general, the percent volume of immature organisms eaten increased from January to September and then decreased. Lepidoptera, Coleoptera, and Pulmonata comprised 25.7, 13.2, and 12.0 percent volume, respectively, of ingested material; Coleoptera and Pulmonata showed the grea.est frequency of occurrence. The diet of the green frog was strongly influenced by the habitat and by seasonal variations in the availability of prey organisms. INTRODUCTION The green frog, Rana clamitans, is a prominent and widely distributed anuran throughout the eastern United States. Although an inhabitant of a wide variety of permanent aquatic sites throughout much of its range, this frog shows a preference for spring-fed streams and adjacent swamps in southern Illinois (P. Smith, 1961). Although several publications treat the life history and ecology of Rana clamitans, few reveal studies of its diet. Whitaker (1961) comments on the stomach contents of 31 frogs captured in small-mammal snap-traps; Hamilton (1948) reports on the diet of 434 frogs collected over a 20-year period from various localities in New York state. Other writers provide only broad generalities (P. Smith, 1961; Pope, 1947; Parmalee, 1954; and H. Smith, 1950). Our investigation is the first consecutive 12-month food-habits study of this species from a single area, and it is the first major report on this amphibian's diet in the Midwest. This research represents a contribution from Project No. 10, Cooperative Wildlife Research Laboratory, Southern Illinois University. A portion of the data has been submitted by the senior author as partial fulfillment of the requirements for the master's degree in zoology. METHODS AND MATERIALS A total of 475 frogs were examined, from collections made weekly during 12 consecutive months, March, 1963 February, 1964, in and 1 Current address: Department of Zoology, University of Oklahoma, Norman 73069. 169 This content downloaded from 157.55.39.110 on Sun, 04 Dec 2016 04:54:54 UTC All use subject to http://about.jstor.org/terms 170 THE AMERICAN MIDLAND NATURALIST 76(1) around Larue Swamp, adjacent to Pine Hills, Union Co., Illinois. The topography of this region reflects an ancient oxbow of the Mississippi River. The swamp, seldom exceeding 1 m in depth, is fed by a number of springs, which flow from the base of adjacent limestone bluffs. The deeper impressions left by the old cnannel form a constantly inundated swamp. The floristic characteristics of the area have been reported by Ashby and Kelting (1963) and Mohlenbrock (1959). Frogs were taken where their numbers seemed greatest; this resulted in the exploitation of three general habitats during the year. When cold weather prevailed, December through February, collections were restricted to the spring-fed streams that flow into the swamp. During March through May, frogs were collected while they used the flooded woodlands and roadside ditches adjacent to the swamp. Frogs were taken in the swamp proper June through November. Most of the collecting was done at night. Soon after capture, the frogs were frozen; at a convenient time they were thawed and processed, wAth age, sex, snout-vent length, body weight, and reproductive condition recorded for each animal. The criteria for maturity were the appearance of secondary sexual characteristics, stage of development of the reproductive system, and snout-vent length. Stomachs were removed and placed in separate, labeled vials of 10% formalin. For each month's sample of frogs, the stomachs were separated into adult male, adult female, juvenile male, and juvenile female categories. The stomach contents of each category were identified to families and their volumes determined by use of the water displacement method. Food organisms were classified as follows: immature or mature; terrestrial or aquatic. Food items were analyzed so, as to reflect percent frequency of occurrence and percent composition. RESULTS AND DISCUSSION Most of the green frog population was in hibernation during the winter, and their food gathering reflected this period of inactivity; over 60% of the stomachs representing December to February collections were empty (Table 1). During these months juveniles tended to be more active feeders than adult frogs, as evidenced by the greater percentage of empty stomachs recorded for the latter. The age groups differed with respect to the sites occupied at the time of collection. Adults usually hibernated in restricted chambers within rock piles or beneath plant debris; juveniles were more often in locations with access to passing prey organisms. Also, in November when cold weather set in, adult frogs were scarce while juveniles were readilv collected around the border of the swamp. Except during February, adult frogs ingested greater quantities of food than young frogs (Table 2). For all months combined, 204 stomachs from adults contained an average of 0.29 ml of food, whereas 271 stomachs from juveniles averaged 0.14 ml. This content downloaded from 157.55.39.110 on Sun, 04 Dec 2016 04:54:54 UTC All use subject to http://about.jstor.org/terms 1966 JENSSEN ET. AL.: FOOD HABITS OF GREEN FROG 171 In adults, the sexes differed markedly in food intake; females tended to ingest more than males, exc.ept in April and August when this trend was reversed (Table 2). From March through May and September through November the average volume of food ingested by TABLE 1 -The percentage of empty stomachs found in green frogs collected March, 1963 February, 1964,,Larue Swamp, Pine Hills, Union County, Illinois Month of All collection Adult Juvenile Male Female frogs Jan. 75.0 58.3 50.0 72.2 62.5 Feb. 80.0 42.9 70.6 50.0 62.1 Mar 0.0 0.0 0.0 0.0 0.0 Apt 6.7 0.0 0.0 5.3 2.3 May 0.0 0.0 0.0 0.0 0.0 Jun. 10.5 0.0 7.7 0.0 5.0 Jul. 4.5 0.0 5,0 0.0 2.4 Aug. 10.5 4.0 13.6 0.0 6.8 Sep. 0.0 3.7 5.9 0.0 2 6 Oct 8.3 6.7 10.5 5.0 7.7 Nov 33.3 13.0 29.2 11.8 22.0 Dec 66.7 63.0 63.2 65.2 64.3 All months 20.6 15.9 19.4 16.3 17.9 TABLE 2.-The sample size and average volume of stomach contents of green frogfs collected Mar., 1963-Feb., 1964, Larue Swamp, Pine Hills, Union County, Illinois ALL ADULT JUVENILE MALE FEMALE FROGS

A population of Anolis nebulosus located near Tepic, Nayarit, Mexico was studied in the field and laboratory from June, 1965 to September, 1968. The population showed a female : male sex ratio of 50:49. The males in the spring were larger than the females, averaging 41.4 and 35.8 mm, respectively; however, no difference in the length-weight relationship occurred between the sexes. The Nayarit study area supported 90 lizards totalling 120 gm/1,000 m2 during the spring, prior to breeding. Few lizards appeared to live more than a year in nature. A. nebulosus were limited baskers, seeking shade when their cloacal temperatures reached approximately 29.7 C. There was a partial subdivision of the habitat between the larger males and the remaining members of the population with regard to perch height and microhabitat. Males also had much larger home ranges than females, averaging 1.99 + 0.23 and 0.62 + 0.14 m2, respectively. There was a trend for the bigger animals to possess larger home ranges. The home ranges were not uniformly distributed on the study area, but were associated with certain features of the habitat. While the home ranges of the large males overlapped those of the smaller males, the large male home ranges were exclusive of those of other large males. Few home ranges of females touched one another, yet the distribution of female home ranges was an almost perfect overlap with the male home ranges. Males and females shared a common behavioral repertoire, although the frequency of use and social context differed at times. Males and females were territorial and showed pronounced agonistic behavior toward members of their own sex. The reproductive season was correlated with the rainy season. Mating lasted from late May through August, and the appearance of hatchlings from the latter part of August to the end of October. 1.Present address: Museum of Comparative Zoology, Haard University, Cambridge, Mass. 02138. 1. Present address: Museum of Comparative Zoology, Harvard University, Cambridge, Mass. 02138. 1970 JOURNAL OF HERPETOLOGY 4(1-2): 1-38 (1) This content downloaded from 157.55.39.215 on Tue, 30 Aug 2016 05:27:40 UTC All use subject to http://about.jstor.org/terms

One hundred forty-four Rana clamitans tadpoles were collected during April and May 1963 and September 1963 through March 1964 in southern Illinois. The larvae of the April and May collections were approaching or passing through metamorphosis; they exhibited no alteration of diet, even during the initial stages of metamorphosis. However, the tadpoles did fast from approximately the time the forelimbs broke through the body walls until their tails were about absorbed. Water samples were taken with each of the September through March collections. The kinds and numbers of organisms ingested by the tadpoles were proportionally reflected in the water samples; this correlation was statistically significant. It was concluded that green frog larvae are fortuitous and indiscriminate feeders with no apparent food preferences. Premetamorphic tadpoles appear to feed continuously, even in winter.