Swift Fox Symposium
An Overview of Reproductive Processes in Small Canids
Cheryl Asa1 and Carolina Valdespino2. 1Research Coordinator, St. Louis Zoo, Forest Park, St. Louis, MO 63110. 2St. Louis Zoo, and Dept. of Biology, University of Missouri-St. Louis, 9001 Natural Bridge Rd., St. Louis, MO 63121.
There are many aspects of reproduction that, although unusual among mammals, are common across canids that have been studied. These include, for example, monogamy, monestrum with exceptionally long proestrous and diestrous phases, a copulatory tie, incorporation of adult young into the social group, behavioral suppression of mating in these subordinate young, obligate pseudo pregnancy in subordinate females, and alloparental care. However, this pattern is based predominately on observations of larger species such as the gray wolf, coyote, and African wild dog. Although data from smaller species, save the red fox and its ranched form, are sparse, these more limited reports suggest some interesting differences. For example, smaller species may be more likely to have a second estrus per year, whereas one estrus and litter annually is typical for larger species. In fact, bush dogs may be polyestrous, a marked divergence from the canid norm. It is clear that more research with the smaller canids is needed, rather than relying on data from the larger species, especially when conservation decisions involve calculations of the reproductive potential of populations.
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