Marmots are among the most abundant order of animals on earth-- rodents. They are the largest member of the ground squirrel family (see taxonomy), and are very adaptive, as witnessed in their diversity in social behavior, and mating habits. There are currently 14 species of marmots in the world; there are eight in the "old world" and six in the "new world."

Yellow-bellied marmots are very easy to recognize; they have the look and build of a prairie dog, and usually have a thick coat of coarse fur, which can be varying shades of brown. They have either yellow or while streaks on their backs and faces. They have claws, as they are fossorial, and require burrows that they usually dig themselves. And as is common to all rodents, they have two prominent incisors, which continually grow. (Please see link to pictures of other marmots for comparison) These species share similar physical features (especially body structure and coloration) as not much has changed due to structural load since they shared a common ancestor. The species itself is a fairly ancient one, as the first known member of species of Marmota existed nearly 9.5 million years ago (Armitage 2001).

Their geographic location and environmental surroundings have shaped the seasonal behavioral patterns of marmots to some degree. After the regression of glaciers, marmots tended to live in mountainous zones, where they could forage for grasses and dig burrows well. Hibernation became an adaptation to low amounts of food and cold temperatures during part of the year. Another testament to the rigors of the environment is the selection pressure towards large body size, large home ranges-- in which adequate food resources can be found, and evidence of reproductive skipping in females. They require the large size because of the harsh environment, which enables them to lose heat less rapidly. Furthermore, being larger they have an active metabolism and digest fats fairly rapidly. It is interesting that here is a case of an anatomical or physiological factor affecting social behavior. Armitage notes that large body size predisposes marmots to mature slower such that they need to be around for at least a year. In order for this work, it is helpful that they retain some level of sociality so they can remain in groups, and reap the benefits of protection that will impact their survival. (Armitage 2001).

The selection pressures marmots faced eons ago have shaped it as a group, so that if we look at some behavior or trait currently and it doesn't make sense to us, perhaps the answer can be seen in light of its evolutionary history connections to how genotypic and environmental, phylogenetic, structural load allow for behavioral responses.

Considerations of Socioecology

In closing, the study of socioecology is a great tool for the analysis of the development of social behavior, but it is still a difficult task to parcel out the factors relating from ultimate and proximate causation, which is presented in the following conundrum, elegantly and eloquently expressed by David Barash.

"Regardless of the general patterns that characterize marmot sociobiology, and despite the seductiveness of working them out, it is also important to recognize that the pattern of social behavior within any colony or local population of marmots is doubtless modulated by such proximate factors as immediate habitat physiognomy, local kinship situations, age and sex composition at any given time, the day-to-day experiences of colony residents with predators, climate and other varying factors, the individual behavior profiles of residents during any given year, the number of such individuals and so forth. On the other hand, regardless, of such proximate factors and their undoubted significance, we should also not miss the forest for the trees: there are patterns, both within and between species, and these patterns tell us something about predictability, order, and the meaning in the life of marmots-and in life itself" (Barash 1989).

This page was created in partial fulfillment of the requirements for Animal Behavior (Biology 323) at Davidson College on April 17, 2002

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