Spotted hyenas can increase survival rates by hunting alone

"Although spotted hyenas are 20 percent more likely to capture prey with one or more members of their social group, cooperative hunting results in multiple new competitors showing up because former allies quickly turn into noisy competitors once the kill is made," she said. "So it's the individual, especially if he or she is low in the hierarchy, that suffers a cost for having group members at that prey."

It is known that more than a million years ago spotted hyenas were solitary scavengers. "My research," said Smith, "shows because there is this cost of competition, that spotted hyenas retained this ability to remove themselves from the larger social group to hunt."

Scientifically speaking, this is known as fission-fusion dynamics – members of the same society repeatedly splitting up from the group (fission) and then reuniting (fusion).

"Human societies exhibit fission-fusion dynamics," Smith said. "For example, we repeatedly depart from our loved ones in the morning and then rejoin them in the evening."

Spotted hyenas, like humans, frequently leave one another but rejoin on a regular basis to maintain social relationships, especially with family members.

Collaborating with Smith were Kay Holekamp, MSU professor of zoology, and fellow MSU students Joseph Kolowski, Katharine Graham and Stephanie Dawes.

A copy of the paper is available online along with more information about the research of Smith and Holekamp. For additional information, go to the Special Report on hyenas.

Contact: Tom Oswald, University Relations, Office: (517) 432-0920, Cell: (517) 281-7129, ; Jennifer Smith, Zoology, Office: (517) 355-3782,