Estrous Cycles, Copulation, and Pregnancy in the Fennec Fox (vulpes Zerda)

Characteristics of estrus, mating, and pregnancy were studied in captive fennec foxes. The monestrous cycles had mean intervals of 9.9 (!1.2) months, whether or not pups survived to weaning. Proestrus, judged by vulval swelling, began 6.5 (!0.7) days before estrus and was not accompanied by sanguineous discharge. Percentage cornified epithelial cells in vaginal smears increased at the time of estrus. In 8 of 10 estrous periods, a single mating followed by an extremely long copulatory lock (mean 1 h 58 min) was observed during continuous video monitoring. In the other two cycles, copulation occurred 2 and 3 times. Patterns of both fecal and serum estradiol and progesterone concentrations during estrous cycles were similar to those reported for other canids.