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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.

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.

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.

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.

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.