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Results of experiments conducted in T-maze to probe the functional role of conspecific odours indicated that whereas the male Indian gerbil,Tatera indica indica invariably prefers odours (from their body, that of the sebum exudation of scent marking gland, urine and faecal matter) of strange males, the females with and devoid of the scent marking gland show slight preference for male odours. However, all the categories ofTatera indica placed their preference for their own odours at the lowest. This behaviour suggests that the role of scent marking to label the habitat for its own use or to signal ‘home’ to the marking animal may not be the sole function of scent marking in this species. It is quite possible that in the desert grassland, scent marking is being used for maintaining a minimum distance between two animals or pairs, as exhibited by the diversity in the occurrence of the scent gland in the field (pair-tolerant) and urban (gregarious social organisation) populations ofTatera indica. This type of spatial distribution, maintained by scent marking behaviour, may be important to withstand the low carrying capacity of the aridland which suffers from almost a perpetual paucity of food.

Four species of Indian desert rodents, viz. Tatera indica, Meriones hurrianae, Rattus meltada and Golunda ellioti have been found to have basal metabolic rates (BMR) lower than the values expected from the metabolic rate-body weight relationship for mammals. The low BMR in these species is evidently not due to any large accumulation of body fats, but is probably related to niche utilization. Of the four species examined, only T. indica and M. hurrianae have any appreciable body fat, presumably for use during summer when scarcity of both food and water prevail.

The anticoagulant chlorophacinone was evaluated in the laboratory for the control of the gerbils Tatera indica Hardwicke and Meriones hurrianae (Jerdon), which are major pests of agricultural crops, grassland and reforestation projects in the arid zone of India. Millet and sorghum grain treated with chlorophacinone was offered in no‐choice feeding tests. The results showed that 100% mortality occurred after seven and five days with 0.0075% chlorophacinone and after three and four days with 0.01% chlorophacinone in T. indica and M. hurrianae respectively. The anticoagulant‐treated bait was significantly less palatable than untreated bait, except bait containing 0.0075% chlorophacinone to T. indica. It is concluded that 0.0075% chlorophacinone can be effectively used to control the gerbils, especially bait‐shy populations previously exposed to zinc phosphide bait. Chlorophacinone appears to give more effective control than warfarin and fumarin, and slightly less effective control than brodifacoum.

The two gerbils,Tatera indica andMeriones hurrianae, and the metad,Rattus meltada pallidior exhibit significant monthly variations in the dimension (maximum length X maximum breadth) of the ventral scent marking gland. Peaks in gland size occur late in winter and monsoon which generally correspond to the maximum breeding activity of these rodents during the year. However, the monthly averages of gland area and incidence of pregnancy in the three species do not follow the same trend. It is difficult, therefore, to conclude if the scent-marking behaviour and the breeding performance of the rodents are inter-related.

Investigations to study the association between hormones and scent marking behaviour in the Indian gerbil. Tatera indica indica Hardwicke, 1807 revealed that castration reduces the frequency of scent as well as urine marking significantly within two weeks. The response of castrated animals to testosterone propionate therapy was gradual and the peak scent marking activity was attained after 8 weeks of administering the injection on a weekly interval.

There are two different patterns of feeding rhythm of the diurnal gerbil, Meriones hurrianae during summer and winter seasons in the Indian desert. The feeding activity is restricted to two phases (6 to 11 a.m.; 4 to 7 p.m.) in summer with an intermediate phase (11 a.m. to 4 p.m.) of complete rest inside the burrow systems. In winter, feeding continues uninterrupted from 6.45 a.m. to 5.15 p.m. During summer, increase in air and or soil temprature suppresses the food intake and general activity of rodents, whereas the rise in these climatic parameters promotes feeding among gerbils during winter season. Two distinct peaks of the feeding cycle during summer (6–9 a.m.; 5–7 p.m.) as well as winter (8–10 a.m.; 3–5 p.m.) periods can be chosen as suitable timings for laying poison baits inside burrows of gerbils.

Brodifacoum, chlorophacinone and coumatetralyl treated pearl millet (Pennisetum typhoides) grains were tested in a desert scrub grassland to evaluate the comparative field efficacy of these three anticoagulant rodenticides. Baits were placed for 10 consecutive days in bait stations in 18 plots of one hectare each in a randomized block design. Per cent reduction in rodent population was calculated by pre and post-treatment active burrow counts, census baiting and live trapping. Results revealed that brodifacoum is significantly more effective than other two anticoagulants. However, analysis of variance revealed significant difference in the estimation of per cent reduction in the rodent population calculated by three methods, the possible reasons for which are also discussed.

[With 4 Tables] A comparison of external body parts and cranial characters in three populations of Cutch rock-rat, Rattus c. cutchicus (Wroughton, 1912) and Soft furred field-rat, R. meltada pallidior (R y 1 e y, 1914) collected from their respective habitats in the Indian desert, has been made. In R. c. cutchicus, males are found to be larger in almost all the characters in Jalore and Jhunjhunu populations, whereas females tended to possess larger values in the Cutch sample. However, inter-population comparison indicated significant differences only for a few characters. In R. meltada pallidior, the male body parts are significantly larger in respect of head and body length and tail length (P

Measurement of the metabolic rates of eight species of Rajasthan desert rodents and of Rattus rattus at a moderately low temperature (21 °C) during winter has revealed that: there is a significant negative correlation (P

Histological structure of the mid-ventral gland and its role in scent marking were studied in the Indian desert gerbil, Meriones hurrianae.

Basal metabolic rate (BMR), evaporative water loss (EWL) within the thermoneutral zone and minimal thermal conductance (C) of the Indian desert gerbil Meriones hurrianae Jerdon, were 0·79 cm3 O2/g/h, 1·89 mg H2O/cm3 O2 and 0·110 cm3 O2/g/h/°C respectively. Below the thermoneutral zone, gerbils regulated their body temperature within the normal limits of homeotherms. The relatively high body temperature (38·7 °C) recorded within the thermoneutral zone is, presumably, the result of an adaptive mechanism for reducing evaporative water loss. The gerbil's low BMR, low conductance (67 and 92 per cent of the values predicted on body weight basis respectively) and its comparatively high body temperature are considered to be physiological means of avoiding overheating.

In a choice test, the Indian gerbils,T. indica preferred urine-mixed food over ordinary millet indicating a phago-stimulant nature of conspecific urine. The experiments also revealed that addition of conspecific urine mitigates the poison aversion and bait shyness behaviour significantly, as a result of which zinc phosphide poisoning can be attempted a second time in a sequence, thus enhancing the control success.T. indica showed a clear preference for urine of the same sex which suggests that the active attractant in the urine has no sex attraction.

Warfarin was evaluated in laboratory against Indian gerbil,Tatera indica and desert gerbil,Meriones hurrianae. Chronic LD50 for the two species was found to be 4 × 19·1 and 4 × l5·9mg/kg respectively. Feeding for 14 days on 0·025% warfarin treated bait provided complete kill in the gerbils but the poisoned bait was less palatable than the plain bait. A period of 18 and 19 days feeding on 0·025% waifarin bait was found suitable to detect resistance to warfarin amongT. indica andM. hurrianae respectively.

Kumari S. & Prakash I., 1983: The mid-ventral gland of the Indian gerbil, Tatera indica and soft-furred field rat, Rattus meltada. Acta theriol., 28, 28: 425—438 [With 3 Tables, 2 Figs. & Plates XIV—XV] The ventral scent marking gland occurs in about 91 and 72 per cent male Tatera indica and Rattus meltada respectively. It is absent in the females of the latter species but is present in about 5.8 per cent female T. indica residing in urban areas and 10.3 per cent female residing in desert grasslands. The gland size is positively and significantly correlated with body weight. The growth of the gland is a continuous process throughout the life of the rodents. No relationship has been found between the gland size and the home range of the rodents. The sebaceous alveoli in the gland of both the species are of typical holocrine type and the epidermal stratified epithelium in T. indica is smooth whereas in R. m. pallidior it is papillaeform. [Coordinating & Monitoring Centre for Rodent Research and Training, Central Arid Zone Research Institute, Jodhpur-342 003, India]

The responses of Meriones hurrianae deprived of food and food-cum-water were found to be similar in respect of time spent in feeding, exploration and drinking whereas water- deprived gerbils fed for a significantly (P < 0.01) shorter time. However, they explored twice (P < 0.01) as long as gerbils in the other two conditions of deprivation. These observations indicate that deprivation of water increases exploratory behaviour among M. hurrianae but food, and food-cum-water deprivation do not seem to influence it. The behaviour of M. hurrianae, when deprived of water, mostly alternated between exploration and drinking whereas feeding was the major behavioural component of the gerbils deprived of food, and food-cum-water. It appears that feeding behaviour among M. hurrianae is of a higher order than drinking behaviour since the animals depend chiefly on the available water content of the food in their natural invironment - the desert.

Behavioural responses of the Indian gerbil,Tatera indica, to conspecific sebum odour of the male ventral marking scent gland were studied in a glass cage and a plus maze. Male and female gerbils were attracted towards the strange male sebum odour though its magnitude was low in females possessing the ventral marking gland, still lower in the females in which the marking gland was absent. The diversity in preferential behaviour of femaleTatera indica is discussed in relation to the role of ventral marking behaviour in chemical communication among rodents. Correlating the results of the experiments with our field observations, it appears that the function of scent marking inT. indica is more of a ‘familiarisation’ nature to label the habitat for its own use in orientation or to signal ‘home’ to the marking animal.

Dokonano porownania wymiarow ciala i czaszki dwu populacji Tatera indica indica Hardwicke, 1807. Zwierzeta pochodzily z miasta Bikaner oraz z naturalnego środowiska, z pustyni Rajasthan. Nie stwierdzono roznic istotnych statystycznie w wymiarach ciala miedzy obu populacjami (Tabela 1), ale wiele wymiarow czaszki zwierząt z populacji pustynnej bylo wiekszych niz u lowionych w Bikaner (Tabela 2). Oceniono rowniez dymorfizm plciowy w obu populacjach (Tabela 3). Wymiary ciala populacji z pustyni Rajasthan porownano z danymi dla tego gatunku z rejonow Sind i Uttar Pradesh (Tabela 4).

Celem pracy bylo uchwycenie prawidlowości w dynamice wystepowania szkod wyrządzonych na polach przez dziki (Sus scrofa Linnaeus, 1758) w rocznym cyklu rozwoju upraw polowych, porownanie wielkości szkod oraz okresow ich nasilenia w 3-ch rejonach kraju: poludniowo-zachodnim, środkowym, polnocno-wschodnim (Ryc. 1) oraz porownanie wielkości szkod w poszczegolnych uprawach.

Held trials were conducted in 18 1‐ ha plots arranged as a 6×3 randomised block to evaluate brodifacoum (0.002%), chlorophacinone (0.0075%) and coumatetralyl (0.0375%) for the control of desert rodents, predominantly Meriones hurrianae Jerdon. Success was measured by counts of inhabited burrows before and four days after the treatment period of ten days. Average kills were 90.5, 83.2 and 81.1 % respectively. It is concluded that all three poisons are effective, but brodifacoum performed significantly better than either chlorophacinone or coumatetralyl.