Cooperative Behavior

There is a good degree of cooperative behavior in the yellow-bellied marmot. Kin selection plays a large role in this. Within matriline cooperation consists of amicable social interactions such as allogrooming, greeting, and cooperative defense of the home range (Armitage & Schwartz 2000). Because the females are related the yearling females often help the breeding females care for the young. This is cooperative because it is beneficial to both the mother and the juvenile. It increases the survival rates of the litter, which in turn increases the mother's fitness. Furthermore, it aids in increasing the juveniles' reproductive fitness because it is teaching them how to be good mother's in the future.

Another trait of the yellow-bellied marmot that exhibits cooperative behavior is their alarm calling system. Marmots often feed together and keep a close look out for predators. When a predator is sighted by one member of the colony, an alarm call will be given to warn all the others. This is an example of cooperation between kin. The mjority of researchers which adhere to the inclusive fitness theory as underlying alarm calling in yellow-bellied marmots imply that indirect fitness is what plays the most important role in the evolution and maintenance of alarm calling. There is one new study, however, that found alarm calling to be a means of increasing ones direct fitness. Blumstein et. al concluded that alarm calling in the yellow-bellied marmot is a form of direct parental care and thus increases direct fitness (Blumstein et. al 1997). Whether or not alarm calling increases direct fitness, indirect fitness, or both, it is clear that it is not a selfish or competitive act.

Competition

There is competition both between and within yellow-bellied marmot matrilines. Between matriline competition consists of infanticide, agonistic behavior and reproductive suppression. Within matriline competition consists of agonistic behavior towards close kin and reproductive suppression of daughters by their mothers (Armitage & Schwartz 2000).