ADAPTATIONS OF FEMALE LIONS TO INFANTICIDE BY INCOMING MALES. By: Craig Packer, Anne Pusey, Karen McComb, Jon Grinnell

Lion Social Habitat Some Facts… Prides of 2-18 adult females with cubs Coalition of 1-7 adult males Males come and go Communication involves roaring Infanticide is common

Location of Field Studies Numerous river courses Lions are able to conceal themselves

Experiments #1 Female response to infanticide Increased cub mortality during male takeovers #2 Females can distinguish between the roars of familiar and unfamiliar males and unfamiliar females

Questions??? Why and how does infanticide occur in a given population of lions? How do female lions adapt to it? Effect of infanticide on lion population and overall fitness?

Methods (#1) 15 prides of lions were studied ( ) in Serengeti National Park, Tanzania Infanticide occurrence, female behavior, incidence of wounds, and mating activity were recorded during male takeovers

Methods (#2) Playbacks of roars from fathers of cubs, from unfamiliar males and from unfamiliar females were given to female lions with cubs Behavior of female lions with cubs was documented based on the responses to these playbacks  Retreating  Approaching speakers  Moving towards their cubs  Snarling

Results (#1) Infanticide was observed 6 times Cub mortality higher during male takeover None of the cubs survived up to 6 months during takeover Cubs aged months were evicted Overall male takeover had a detrimental effect on the fitness of females

Results (#1 cont.) Responses of mothers to incoming males at takeovers Defense of cubs Avoidance of new males Heightened female sexual activity Low fertility period

Mating Levels

Results (#2) Females and cubs agitated in response to playbacks of roars of unfamiliar males Retreating-common response to roars of unfamiliar males Females also moved towards the cubs in response to roars of unfamiliar males

Results (#2 cont.) Females with cubs approached speaker in response to playbacks of unfamiliar females No movement towards the cubs in response to playbacks of unfamiliar females Cubs participated in all activities together with mothers

Data (#2)

Discussion Heightened female sexual activity and low fertility during takeovers elicits competition between male coalitions for control of the pride --> results in larger coalition It is adaptive, females need protection from male harassment Only large male coalitions remain in a pride for more than 2 years Periods of infertility improve females reproductive success

Discussion cont. Females can discriminate between roars of unfamiliar and familiar males, and unfamiliar females Encounters between alien males and females with cubs are very costly for the females Vocal recognition has been demonstrated in lions Grouping by females appears to be an important adaptation to infanticide by males

Future Research Other prides in different areas should be studied Other mechanism of female defense are interesting Infanticide in larger coalitions Further playbacks would be necessary to see if cubs are able to distinguish between vocalizations Evolution of the skills of social cognition

Critiques Small groups studied Data for Part I inconclusive Difficult to observe (lions conceal themselves) Difficult to determine cub age (cubs are hidden after birth) More methods of protection should have been studied