Rodents odours

A possible alternative is the microvillous part of the chemosensory epithelium in the Organ of Rodolfo-Masera (Septal Organ), which is VN-like (Taniguchi etal., 1993). This mixed receptor population requires much further study since it could prove to have intermediate odourant sensitivities (Giannetti et al., 1995). Its distribution and function(s) are still incompletely known however it is sufficiently widespread, from Opossums to Rodents, to warrant an intensive survey (Rodolfo-Masera, 1943 Kratzing, 1978 Giannetti et al., 1992 and 1995). 

Ultra-sound emissions typically occur when male rodents are exposed to female odours or altricial neonates to maternal sources (Whitney, 1974 Conely and Bell, 1978). Without the VNO, sexually inexperienced male mice do not utter emissions at ultra-high frequencies (UHF), whereas those with prior experience vocalise after VN-x, as discussed above (Chap. 5). Female mouse urine contains a unique UHF-eliciting component which is non-volatile but ephemeral (Sipos et al., 1995). The signal is degraded by oxidation and disappears within 15 to 18 hours of deposition. Direct contact with freshly voided urine must occur before males will vocalise (sexually experienced or inexperienced). At least one of the olfactory systems is needed for UHF to be elicited by fresh urine complete deafferentation abolishes the response (Sipos et al., 1993). Exposure to females permits UHF to be elicited by other than chemical cues (Labov and Wysocki, 1989). Nocturnal or cryptic species conceivably use ultrasound to advertise male presence whether this is to deter other males or assist with female location is unclear. 

Abstract For most mammals, the ability to detect odours and discriminate between them is necessary for survival. Information regarding the availability of food, the presence of predators and the sex, age and dominance status of conspecifics is odour mediated. Probably because of this extraordinary reliance upon odour cues, mice and rats have developed the ability to learn and remember information associated with olfactory cues as effectively as primates recall visually related cues. As a result, these rodents have become the model of choice to study the neural and cognitive processes involved in olfactory discrimination. In this paper, we describe some of the more ethologically based tasks used in assessing olfactory discrimination and the advantages and disadvantages of the different methodologies employed. 

Seasonal Responses to Predator Faecal Odours in Australian Native Rodents Vary Between Species... 

This study describes the response of three native Australian rodent species in North Queensland rainforests to predator faecal odours. We examined the questions ... 

Rodent visitation rates to odour stations decreased in the presence of predator faeces, compared to blank and novel odours. The response to different predators varied seasonally, and encompassed avoidance of familiar and unfamiliar faecal odours from marsupial and eutherian predators. This study supports the scat avoidance hypothesis (sensu Banks et al. 2003), which predicts that faeces are a useful indicator of predator presence, and I thus argue that, at least in the present context, faecal odours could be a good cue of predator presence for rainforest species. 

Hayes, R. A., Nahrung, H. F. and Wilson, J. C. (2006) The response of native Australian rodents to predator odours varies seasonally a by-product of life-history variations Anim. Behav. 71, 1307-1314. 

Watts, C. H. S. and Aslin, H. J. (1981) The rodents of Australia. Angus and Robertson, Sydney. Wolff, J. O. and Davis-Bom, R. (1997) Response of gray-tailed voles to odours of a mustelid predator a field test. Oikos 79, 543-548. 

Addo Elephant National Park (AENP), elephant population at, compared to free-ranging population at Ndarakwai Ranch, Tanzania, 82-88 Adrenaline, from cane toad skin secretion, 412 Adult odour preferences in rodents, role of early olfactory learning in development of, 251-258... 

The most selective known poison for mammals is norbormide 4.90) a rat-killer. It is 5-(o -hydroxy-Q -2-pyridylbenzyl)-7-(a-2-pyridylbenzylidene)-5-norbornene-2,3-dicarboximide. Only the genus Rattus is affected, and death follows its powerful and irritant local vasoconstrictor action this leads to ischaemia of most of the vital organs which then cease to function. It is non-lethal to over 30 species of other mammals (including mice and other rodents), birds, and fish. It is suggested that all animals other than rats can detoxify norbormide (Roszkowski, 1965). Norbormide has not proved very successful in rat extermination because the vermin soon recognize its odour and learn to avoid it. 

Schellinck, H. M. 1995. The influence of the major histocompatablility complex, gut bacteria and diet in the production of odours of individuality in rodents. Unpublished doctoral dissertation, Dalhousie University. 

Brown, R.E. 1985. The rodents I effects of odours on reproductive physiology (primer effects). In Social Odours in Mammals (Ed. by R.E. Brown D.W. McDonald), vol 1, pp 245—344. Oxford Clarendon Press. 

Daly, M., Wilson, M.J., Behrends, P. 1980. Factors affecting rodents responses to odours of strangers encountered in the field experiments with odour-baited traps. Behav. Ecol. and SociohioL, 6, 323—329. 

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