Squirrels by Jr. Richard W. Thorington

Author:Jr. Richard W. Thorington
Language: eng
Format: epub
Publisher: Johns Hopkins University Press
Published: 2006-03-14T05:00:00+00:00

Chapter 6

Reproduction and Development

How do squirrels reproduce?

REPRODUCTION IN TREE AND FLYING SQUIRRELS. For many tree squirrels and flying squirrels, courtship involves a mating chase. One to many males are attracted to an estrous female by several different cues, including her vocalizations, behavior, and odor. In female eastern gray squirrels estrus lasts only one day. As males congregate near the female, they jockey for the best position—which is as close to her as possible. The dominant male, closest to the female, will cautiously try to approach and mate with her, but she will fend him off. At the same time, the male must watch his back and continue to defend his dominant position from other males. For a while, the situation will be a stalemate. Without warning, the female will race away, and the dominant male and any other males that can keep up will run after her. This is the part of the mating chase that is commonly observed—a female bounding quickly up a tree or across a yard to a hiding place, while a chaos of males tries to follow her or locate her. While hunting for the female, mostly through scent, the males give a characteristic call, described as “muk-muk . . . muk-muk . . .” in the eastern gray squirrel.

The first male to locate the female may mate with her. If another male discovers the mating couple, he will rush in and break up the mating. Mating attacks can be vicious. We observed a male red-tailed squirrel (Sciurus granatensis) in Panama break up a mating bout by biting the other male in the scrotum. The female can get hurt as well. During a mating chase of fox squirrels in Florida, we saw a female with a large, fresh gash on her thigh, which probably resulted from such an attack. After the female squirrel mates with one male, the whole mating chase may be repeated. We have observed a female mating with as many as four males during the course of a morning, but others have described a more monogamous situation. By early or midafternoon, the female will become less receptive to mating and the males will lose interest in pursuing her.

For the most part the most dominant males in a chase are the oldest males, but younger squirrels (less than 2.5 years of age) are not excluded from mating. According to studies conducted at the University of Kansas by John Koprowski, young males use an alternative strategy. Young males hang about inside the female’s home range but do not actively participate in the chases. When the female breaks away from the chase group and hides, the young males go looking for her. In this situation, says Koprowski, these young males have as good a chance of finding the female and mating with her as the older males.

Other Holarctic tree squirrels, such as the North American red squirrel and the European red squirrel, exhibit the same reproductive behavior. African and Asian tree squirrels are less thoroughly studied,

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