雌狮是民主派（Lionesses Are Democrats）_生物论文

　　In any prideof lions, a "lion king" typically sires most of the cubs. But there‘sreally no such thing as a "lion queen," according to a studypublished in this week’s Science.Instead, female lions all bear about the same number of young--an unusualbehavior for social mammals. "The queen of beasts is a democrat,"says behavioral ecologist and main author Craig Packer of the University ofMinnesota, Twin Cities.

　　Togetherness. In contrast to males, female lions in a pride have about equalreproductive success and even cooperate in raising their young.
CREDIT: C. PACKER/UNIVERSITY OFMINNESOTA

　　Together withcolleagues Anne Pusey and Lynn Eberly, Packer has been observing lions in Tanzaniasince 1960. A decade ago, the team‘s DNA analysis showed that most of theoffspring in each pride belonged to one of two dominant males. In this study,they analyzed 36 years’ worth of birth records in which they kept track ofevery cub reaching its first birthday in some 31 prides and identified itsmother. "That they looked across a large number of groups over a long timemakes this a powerful [study]," says Jeffrey French, an animal behavioristat the University of Nebraska, Omaha.

　　The number ofyoung varied from pride to pride: In some, the females had just one or two cubsa year, whereas in others, they tended to have three or four and occasionallymore. But within a pride, Packer says, there was no hint that any females weresystematically getting more reproduction than others. Indeed, the more mothersin a pride, the likelier the cubs were to survive. Such behavior is atypicalfor social mammals, in which it is common for an alpha female to sabotage thereproductive efforts of others.

　　Why do lionesses get along better? For starters, Packersays, a pecking order would lead to "mutually assured destruction"from the animals‘ massive claws and teeth. Lionesses also avoid anotherstrategy used elsewhere in the animal kingdom: killing the rivals’ newbornyoung. This likely stems from breeding in communal locations. But like othercats, lionesses go into hiding to give birth and don‘t rejoin the pride untilthe cubs are 6 weeks old and much less vulnerable. Returning mothers then raisethe cubs communally and together fend off raids from lions in other prides.

摘自：science.now