In any pride of lions, a "lion king" typically sires most of the cubs. But there's really no such thing as a "lion queen," according to a study published in this week's Science. Instead, female lions all bear about the same number of young--an unusual behavior for social mammals. "The queen of beasts is a democrat," says behavioral ecologist and main author Craig Packer of the University of Minnesota, Twin Cities.
Together with colleagues Anne Pusey and Lynn Eberly, Packer has been observing lions in Tanzania since 1960. A decade ago, the team's DNA analysis showed that most of the offspring 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 of every cub reaching its first birthday in some 31 prides and identified its mother. "That they looked across a large number of groups over a long time makes this a powerful [study]," says Jeffrey French, an animal behaviorist at the University of Nebraska, Omaha.
The number of young varied from pride to pride: In some, the females had just one or two cubs a year, whereas in others, they tended to have three or four and occasionally more. But within a pride, Packer says, there was no hint that any females were systematically getting more reproduction than others. Indeed, the more mothers in a pride, the likelier the cubs were to survive. Such behavior is atypical for social mammals, in which it is common for an alpha female to sabotage the reproductive efforts of others.
Why do lionesses get along better? For starters, Packer says, a pecking order would lead to "mutually assured destruction" from the animals' massive claws and teeth. Lionesses also avoid another strategy used elsewhere in the animal kingdom: killing the rivals' newborn young. This likely stems from breeding in communal locations. But like other cats, lionesses go into hiding to give birth and don't rejoin the pride until the cubs are 6 weeks old and much less vulnerable. Returning mothers then raise the cubs communally and together fend off raids from lions in other prides.