Reproductive Biology of a Tropical, Non-Hibernating Ground Squirrel

Abstract

To examine the effects of climate and hibernation on reproductive patterns, I compared tropical and temperate species of ground and tree squirrels. I studied the reproductive biology of a tropical species, the Cape ground squirrel ( Xerus inauris ), by observing marked individuals in the Kalahari-bushveld region in Namibia. Breeding occurred throughout the year, although there was some seasonality. Interestrous intervals were 76.5–146 days, gestation averaged 47.7 days, lactation averaged 52 days, there were one to three litters per year, with litters of one or two young. Subadult males reached reproductive maturity at 8 months, while females had their first estrus at 10 months. Comparisons of these reproductive traits with other species in the family Sciuridae suggest that reproduction in the Cape ground squirrel is influenced by a long active season in an unpredictable habitat. Of the potential factors affecting reproduction in squirrels, I conclude that climate is the most critical, and nutrition, predation, and allometry are less important.