There is mounting evidence that menopause evolved via
inclusive fitness benefits gained by helping kin; both postreproductive
humans [11–14] and killer whales [15] increase
the reproductive success and/or survival of their relatives.
But how postreproductive females help their kin remains
enigmatic. Individual animals gain knowledge about their environments
as they age [16–18] and can transfer this information
to group mates [19]. Like early humans, killer whales and pilot
whales rely on food whose availability varies widely in space
and time [20, 21]. One hypothesis for the evolution of menopause
via inclusive fitness is, therefore, that postreproductive
females buffer their kin against environmental hardships by
storing and providing ecological information on the location
and timing of resources [7, 8]. But this hypothesis remains
untested.