veille

Why wait to mark? Possible reasons behind latency from olfactory exploration to overmarking in four African equid species

Abstract

Whereas most studies on overmarking in mammals analysed the rate of overmarking, that those investigate time between exploration of an olfactory stimulus and the response to it remain less common, with inconsistent results. We examined the latency in time between elimination by the sender and sniffing by the receiver, and from sniffing and overmarking, in four captive African equid species to explore differences among species, and among age and sex classes. We investigated these latency time periods in light of three potential hypotheses explaining overmarking behaviour in equids: social bonds, group cohesion, and intrasexual competition. Analysing 1684 events of sniffing and 719 of overmarking among 130 individuals, we found that (i) the time from elimination to overmarking was shorter among female friends and in parent–offspring dyads, proving support to the social bond hypothesis; (ii) intraspecific differences in time periods do not reflect the social organisation of species, thus not supporting the group cohesion hypothesis; (iii) males were more attracted to elimination of conspecifics than females, and female’s eliminations were inspected longer, in line with the sexual competition hypothesis and/or reproductive behaviour. In addition, we found that the younger foals came to sniff eliminations faster than older ones, and in larger groups foals devoted longer time to sniffing the elimination before overmarking. We concluded that examination of the elimination could be driven by motivations other than the decision to overmark. Whereas overmarking serves to express bonds to a familiar individual, the latency of overmarking reflects more reproductive interests.

veille

The daily and seasonal behaviour of the American mink and the coypu, two invasive species from the Záhorie PLA (Slovakia)

Abstract

The activity of small invasive mammals, the American mink (Neovison vison) and the coypu (Myocastor coypus), was monitored in western part of Slovakia. Camera traps were located at 9 localities where these animals occur and were monitored throughout all four seasons. The activity of these two invasive species was analysed with regard to the habitat type and environment and, but especially, to the relationship to season, daily period, part of the day and activities. The following animal activities were observed: environmetal exploration, movement, swimming, stationary, grooming, play, flee, feeding, change of environment, mating behaviour and territorial marking. In case of the coypu, crepuscular and nocturnal activities were prevalent. Activity during daytime occurred mostly during winter days with low temperatures. On the other hand, American minks were mostly diurnal. The shift in behaviour compared to American minks in their native environment could be a sign of its adaptation to a new environment. Our research also showed seasonal changes in activity of both invasive mammals. This research could serve as a basis for management schemes to combat the presence and dispersal of these two invasive mammal species.

veille

Assessing the performance of brushtail possums (Trichosurus vulpecula) on the Mechner counting procedure

Abstract

This study assessed brushtail possums’ performance on the Mechner counting procedure. Six brushtail possums were required to produce different Fixed-Ratio (FR) response targets by lever pressing. Their responses provided access to food reinforcement delivered either upon completing the target FR response requirement on a single lever or, in different conditions, on completing the target FR before producing an additional response on a second lever. The mean number of responses on the first lever before switching to the second lever typically occurred just above the target FR response requirement (FR: 4, 8, 16, 32 and 64). The variability in the number of switches between the levers around the target FR decreased from the first 10 days to the last 10 days, indicating an improvement in counting accuracy over sessions. The time to switch between the first and second lever was consistently variable across response requirements suggesting that it is unlikely the possums were using time to predict when to switch levers. This research further supports the use of the Mechner procedure as a method for measuring counting ability in animals and confirms the possibility of numerical competence in a marsupial species.