vidual territories often are bordered closely by other neighboring colonies. Each colony is comprised of a single dominant male residing over a harem of up to two or three breeding females and a collection of adolescents. The males are extremely territorial and will aggressively defend their harem and ter- ritory from any rival male challengers. But the harem’s loyalties are short lived and after three years of apparent marital bliss the ladies seem tired of the male and send him packing. Reluctantly, I’m sure, he leaves the burrow in order to seek out a different location and find new digs, all inclusive of a new harem. As the name would seem to in- dicate, the fur of the yellow-bellied marmot is usually yellow or yellowish- brown in color and sometimes tipped with white, which can give it a frosted appearance. Coloration, however, can sometimes vary significantly from area to area, colony to colony, and even animal to animal. Like the badger, the outer hair of the rockchuck is fairly long and coarse, but the under-fur is wool- like and much softer. Its tail is short … only about one-third as long as its body. There is nothing typical about a rockchuck’s size. The young, venturing out of the den for the first time in the spring, frequently can be only a little larger than a bulging bellied prairie dog … at around three pounds. But a full-grown adult can tip the scales at a whopping 12 pounds and measure 17 to 22 inches in length. Clearly, this makes the yellow-bellied marmot one of the largest of our rodent species. The wobbling side-to-side move- ments of a rockchuck rushing to regain the security of its den reminds me of a poorly loaded packhorse with panniers flopping back and forth. The sight of this, or even the thought of it, always tends to make the corners of my mouth turn upward. But while these comical movements may appear on the surface to be slow and deliberate, no one should misconstrue them as such. Even when a rockchuck is abruptly awakened from its seemingly unconscious state of sun- ning itself on the rocks, the speed at which it can regain the safety of its den is nothing short of phenomenal. Fre- quently, this quick evacuation comes as a direct result of a shrill whistling bark sounded by the colony sentry, who has been given the responsibility to
monitor the area for potential threats or invasions. I have no idea how the sentry duties are assigned; I only know that at least one member of the colony is gener- ally saddled with those responsibilities and when any threat is perceived it is the sentry’s obligation to alert the other members of the colony.
The life expectancy of rockchucks is considered to be on the average from 13 to 15 years. Outside of a varmint hunter’s bullet, predation comes in the form of a long list of formidable bird, animal and even reptile enemies, in- cluding: bears, wolves, coyotes, foxes, wolverines, badgers, cougars, owls, eagles, large hawks, snakes and virtu- ally any carnivore looking for an easy meal of plump rodent. The common practice of rockchucks digging their dens directly underneath heavy rock
formations provides a degree of security from predation. Doing so shelters the den from attacks from above from the winged critters and it also provides an impediment to the ground-excavating foe, like badgers and coyotes. Marmots breed only once per year.
Following a 30-day gestation period, the young typically are born in May or June. A litter may have up to nine young, but three to five pups are considered the norm. At the age of two years both the females and males are considered sexu- ally mature, but most mating doesn’t take place until they reach their third year. The females are allowed to remain on a permanent basis within the birth mother’s colony, but generally only about half stay on a permanent basis, with the remainder wandering out to join new colonies. The males, on the
As a bonus, sometimes you get lucky and find both rockchucks and ground squirrels in the same location.
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