How many rocks could a Rock-Chuck chuck?

Rock Chuck or Wood Chuck, both are marmots. The correct name however, for our local marmot, is the Yellow-Bellied Marmot. The marmot is the only mammal to have a USA holiday named for it (Ground Hog Day).

This large (14” to 20”) rodent loves rocky terrain where they can lay in the sun and also escape predators when alarmed. One individual always stands guard and gives an alarm call. The call will vary according to the type of predator (hawk vs. coyote, etc). It may be a “chuck”, whistle, or a trill. Rock habitats must be close to greenery, as the animal lives entirely on green vegetation of all types.

Yellow-Bellied Marmots spend 80% of their lives in burrows – this includes nighttime, as well as hibernation which lasts from August through February. They are meticulous about keeping their den and bedding clean. Their hearty appetite allows them to put on a good layer of fat for their 7 month hibernation. Sleeping late, then eating vigorously, and finally resting on a rock in the sun conserves the energy that turns into a layer of fat.

The males are “harem-polygymous” and litter sizes average a bit over 4 pups. Males leave the colony, but females tend to stay with their mothers and become reproducers at 2 years of age.

This “bear-like” rodent has a golden to rufus coat, brown head, and a yellowish-red belly. Wood Chucks are found in the east, but Yellow-Bellies are a western, intermountain species.

They are most interesting to observe, whether sunning on a large rock or scurrying across a road or trail into the closest cover.

(A big one sunning – a favorite pastime)

The Effects of TORPOR or Lack thereof

There are several definitions of torpor: sluggishness, apathy, suspension of physical powers, or dormancy. ESTAVATION is a summer torpor that occurs with species that live in warm climates. It occurs during the hottest time of the year. HIBERNATION is winter torpor. We, here in Idaho, are most familiar with this type. All species go through some type of torpor. Nocturnal animals sleep during the day, and diurnal species do the opposite.

Torpor is an involuntary thing. The HYPOTHALAMUS is the part of the brain that controls body temperature, hunger, sex drive, moods, and sleep (TORPOR). Changes in the weather or fatigue can stimulate the onset of torpor. When waking from torpor, hibernating animals waken very slowly and are very groggy.

HISTAMINE is an organic, nitrogen compound involved in immune responses and physiological functions. It is believed that the production of this chemical is a natural inducer of hibernation (torpor).

Bears and many rodents are not true hibernators. Their heartbeats and temperatures do not go down to the degree that other hibernators do. This allows them to awake periodically to eat from a food cache, defecate, and drink.

An interesting study with chipmunks has shown that lack of torpor can kill.When winters are warmer than usual, these rodents fail to go into their natural torpor cycle. The results are that about a 90 percent loss of life occurs within a population that doesn’t get the required sleep. This is contrasted against a 90 percent winter survival rate with populations that get the needed sleep.

Living Without Water: A Desert Adaptation

Water is essential to life. That being said, how do desert animals get by with practically none? One way is to conserve body moisture by being nocturnal. However, some rodents, such as the Kangaroo Rat and the Round-Tailed Ground Squirrel, have the ability to manufacture their own water from seeds.

The carbohydrates in seeds make this possible. The chemical make up of a carbohydrate is that every atom of carbon is attached to a molecule of water (C H2O). Simple sugar, the basic carbohydrate, is C6 H12 O6. Hence the term carbohydrate. All animal bodies break these molecules down during respiration in their cells and any excess H2O is excreted in the urine. If this water is retained, the need for additional is satisfied.

One would probably not expect to see much life in a desert because of the harsh conditions. It is always amazing to me to witness the variety of species we encounter there. Besides the birds, a favorite rodent of mine is found in arid areas.

The Antelope Ground Squirrel is an omnivore. It will consume insects, grasshoppers, and carrion, as well as vegetative matter. This squirrel can also go long periods without water. Unlike other ground squirrels, it does not hibernate. It digs an extensive burrow, two feet under ground, with two or three entrances.

This cute fellow is distinguished by a white stripe on each side of its spine. It prefers open areas and is diurnal (daytime active) which makes it more easily seen.

(An Antelope Ground Squirrel enjoying the cool of the morning)