The economics of scent marking with urine and feces in goitered gazelle (Gazella subgutturosa)

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

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.

Midden site selection in Dorcas gazelle: Larger is not always better

Dorcas gazelles are believed to use middens to mark their territories and transmit information. Given the commitment to maintaining a midden, it is believed that middens are not placed randomly. We examined how the habitat (tree height and maximum canopy) and anthropogenic disturbance (camel and human presence) influenced the selection of midden sites by Dorcas gazelles in South Sinai, Egypt. Our results showed that Dorcas gazelles did not place middens at larger trees, while favoring relatively smaller trees and shrubs where the anthropogenic disturbance and perceived hunting risk are less. Our results, in light of the previous findings, suggest that selection of midden sites is species context-dependent behavior. In areas with less anthropogenic disturbance and hunting, Dorcas gazelles have been shown to select the largest trees of the same species as midden sites. In contract, in our study site with high anthropogenic disturbance and no protection from hunting, gazelles did not utilize the presumably optimum landmarks for midden sites. Our study showed that Dorcas gazelles instead utilized smaller trees and some shrubs that are less conspicuous and presumably less effective as advertisement sites, but safer.

Alarm signals in goitered gazelle with special reference to stotting, hissing and alarm urination-defecation

Compared to solitary species, social ungulates benefit from living in groups not only because of the "many eyes effect", when each individual devotes less time to vigilance and spends more time foraging and engaged in other activities, or of the "dilution effect", when the probability that any specific individual will be caught decreases with herd size, but also because of early alarm signals produced by conspecifics that provide enough time for a successful escape from predator attack. These signals can contain multiple messages about the category of the predator and the degree of risk. Among them, stotting, alarm calls and alarm urination-defecation acts are distinctive channels of prey-predator and/or prey-prey communications. However, stotting gaits and alarm vocalizations are still subjects of numerous debates on their functionality and to whom they are addressed (predator or conspecifics); in addition, alarm urination-defecation is known for a few ungulate species and until now functional significance of this behavior has stayed elusive. I found that stotting and hissing were used by adult females significantly more often than adult males, and that they displayed these behaviors most often at the end of the hiding period and from 2 to 3 months thereafter. Stotting and alarm hissing are likely mainly used to address conspecifics as well as being used by females to warn and manage their fawns in dangerous situations and to teach them to avoid being preyed upon during the initial time after the hiding period. In contrast, alarm urination-defecation acts were displayed by females and males equally and apart of being pure physiological functions and/or a release the stress from encountering a predator, they likely also had significance as an alarm signal, though this association is poorly explored and needs further investigation.