Ecology and Social Behavior of Prairie Dogs

Dr. Hoogland observing prairie dog behavior.

In research that has been supported for many years by the National Science Foundation and the National Geographic Society, John L. Hoogland has been studying the ecology and social behavior of prairie dogs at the Arapaho National Wildlife Refuge in Colorado, which continues his recent work at Bryce Canyon National Park, Utah. Through long-term research with marked individuals, Hoogland is investigating multiple mating by females, incest, killing of potential offspring by males, and alarm calling. Hoogland also is working with the U.S. Fish and Wildlife Service, the Turner Foundation, the National Park Service, and other agencies that are trying to save prairie dogs from extinction.

Juvenile prairie dog at first emergence from natal burrow, when it is about 5.5 weeks old and weighs about 150 grams.Dr. Hoogland's longterm research under natural conditions is accomplished by tracking the survivorship and reproductive success of marked individuals over time. Results have led to a better understanding of several pivotal issues in behavioral ecology and population biology. Some of these issues include competition, infanticide, and inbreeding.

Infanticide:

Infanticide is one of the most intriguing, controversial, and misunderstood issues in behavioral ecology and population biology. Dr. Hoogland's research has found that infanticide accounts for the partial or total demise of 39% of prairie dog litters, making it the major cause of juvenile mortality. The most common killers are lactating females and the most common victims are the offspring of close kin. Mothers probably kill to obtain sustenance via cannibalism during the stressful period of lactation, but convincing evidence for the adaptive significance of infanticide remains elusive.

Kinship:

How important is kinship in the evaluation of possible mates? Should individuals avoid both extreme and moderate inbreeding by maximizing outbreeding via long-distance dispersal?

Factors such as sex ratio among adults, maternal condition, local mate competition, and local resource enhancement do not affect the sex ratio within litters. Consequently, each mother usually weans approximately equal numbers of male and female offspring.

These questions have been the focus of much research but continue to vex psychologists, anthropologists, behavioral ecologists, and population of biologists.

A variety of behaviors and issues related to kinship among prairie dogs have been studied by Dr. Hoogland. Longterm research, involving pedigrees as deep as six generations, is providing important insight. For example, black-tailed prairie dogs have four separate mechanisms for avoiding inbreeding with parents, offspring, and siblings, but individuals regularly engage in moderate inbreeding with more distant kin like first and second cousins.

For praire dogs, learning to identify relatives during a critical period four weeks after weaning is the key to kin recognition among older individuals. Radionuclide experiments have also shown that prairie dog mothers often nurse offspring of other mothers, particularly nieces, nephews, and grand offspring.

Student Research Opportunities:

Dr. Hoogland's research at National Parks such as Wind Cave, Petrified Forest, and Bryce Canyon offers exceptional opportunities to involve students, many of them sponsored by NSF's REU Program (Research Experiences for Undergraduates). Students participate in all aspects of research—from livetrapping and collection of blood samples (for paternity) to statistical analysis and publication of results. Many students have applied their research under Dr. Hoogland's direction toward a senior thesis (e.g., Brown, Davidson, Minnesota, Pennsylvania, Princeton, and Yale). Working with him in the field has helped other students to gain acceptance into graduate schools such as Brown, Cornell, Michigan, Oklahoma, Oklahoma State, Penn State, Princeton, UC-Davis, UC-San Diego, Washington, and Yale.

Project PI:

Dr. John Hoogland