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A Baboon’s Life
New demands will be harder for him because of the nature of cognitive aging.
“Crystallized” knowledge (the recalling of facts and their application in usual,
habitual ways) may remain intact into old age, but “fluid” knowledge (the
absorbing of new information and its improvisatory application) typically slips.
It’s an inauspicious time to learn new tricks.
Physical vulnerability, need for continuity, reliance on the familiar
these elements all suggest that it is madness for an aging baboon to pick up and
try a new life. Why should he ever do so?
A number of scientists have come up with several ideas. Perhaps the aging baboon
believes that a move will allow a last hurrah. Maybe aged males return to their
natal troop, to spend their final years in the care of their aged sisters.
Another theory suggests that aging males may leave the troop when their daughters
reach reproductive age, so as to avoid breeding with them. A particularly
poignant twist on this idea comes from studies of the sifaka, a Madagascan
primate. In a scene that is part King Lear, part bad Marlin Perkins, the
reproductive-age females drive out the elderly fathers. No Hallmark cards there
for Father’s Day.
The data from my baboon studies suggest an additional reason for the occasional
transfer of an aged male. He may move on because the current gang in charge will
not allow him to step down gracefully. When you examine dominance interactions
among individuals in a troop, a distinctive pattern emerges. High-ranking males
have their tense interactions with each other one will force another to
give up a piece of food or a resting spot, or will disrupt grooming or sexual
behavior.
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