"2011/008"
Dotaz
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Overmarking remains an unstudied topic in juvenile mammals. We have previously documented a very high rate of overmarking by foals in four captive African equid species: mountain zebra (Equus zebra), plains zebra (Equus quagga), Grévy's zebra (Equus grevyi), and African wild ass (Equus africanus). African equids vary interspecifically in their social organisation. Since differences in social organisation affect many mammalian behaviours, in this study we investigated interspecific differences in overmarking behaviour of foals, analysing only cases where elimination of any other individual was explored by a foal. We hypothesised that the pattern of overmarking by foals should reflect either differences in social organisation of the species or phylogenetic relations among them. We found that in all species very young foals explored mostly maternal eliminations, and this preference declined with increasing age of the foal and reflected the social organisation of the species; the highest overmarking rate was in species with high intragroup aggression (mountain zebra) and lowest in species with low intragroup aggression and which form crèches (African wild ass). Similarly, the rate of overmarking of the mother, as opposed to other herdmates, was associated with social organisation of the respective species. Thus, we found interspecific differences in overmarking by foals, which were associated with variability in social organisation. Since we also revealed differences between African wild ass and zebra behaviour in early stages of ontogeny, we cannot refute the effect of phylogeny on overmarking behaviour. Additionally, our results supported the identity sharing hypothesis as an explanation of overmarking.
Overmarking occurs when one individual places its scent mark directly on top of the scent mark of another individual. Although it is almost ubiquitous among terrestrial mammals, we know little about the function of overmarking. In addition, almost all studies on mammalian overmarking behaviour dealt with adult individuals. Reports on this behaviour in juveniles are extremely rare, yet may elucidate the function of this behaviour. We tested four mutually non-exclusive hypotheses which might explain this behaviour in juveniles: (1) conceal the individual's scent identity, (2) announcement of association with other group members, especially the mother-i.e., sharing identity with the mother, (3) to prevent the next conception of the mother, i.e., parent-offspring conflict, and (4) an early expression of male sexual behaviour. We observed 43 foals (out of 108 individuals) from all African equid species (Equus africanus, E. grevyi, E. quagga, E. zebra) in five zoos. In total, we recorded 3340 eliminations; 260 of these events were overmarked by 38 individual foals representing all species. This represents one of the highest rates of overmarking ever recorded by mammalian juveniles. Foals of all species except African wild ass overmarked the mother more often than another herdmate: with male foals overmarked at a higher rate than female foals. Mothers preferred to overmark foals, but not exclusively their own foal. Our results provide support for the hypotheses that overmarking serves to share identity between foal and mother, and that it is an early expression of male sexual behaviour.
- MeSH
- feromony * MeSH
- koně * MeSH
- matky MeSH
- odoranty MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
