Vicious social circle

Press, 30 December 1985, Page 16

Vicious social circle

From ‘The Economist,’ London

Male polar bears kill baby bears when given half a chance. Infanticide is a surprisingly common practice among animals, in the wild as well as in stressful ityWhen they take over a pride of lionesses, lions are wont to kill the cubs in the pride. So are male langur monkeys when they take over a troop of female monkeys. But such examples, however horrifying to witnesses, can at least be explained as “rational.” When their suckling offspring are killed, the mothers come into season sooner, so the crime brings

its perpetrator the reward of fathering his own offspring sooner. No such explanation works for a case of widespread infanticide described by Dr John Hoogland of Princeton University in the journal, “Science.” Black-tailed prairie dogs are ground-living squirrels that epitomise cuddly innocence. Yet a baby prairie dog is more likely than not to be killed by an adult prairie dog. Worse still, there is a good chance that the killer will be the baby’s grandmother, half-sister or aunt. Such murderers have no interest in bringing the victims’ mothers

into season — nor does the crime have that effect anyway (prairie dogs conceive only at one season of the year). Their motive is mysterious. But whatever the motive, the animals are caught in a vicious circle. Venturing out of its hole, a female prairie dog dares not go far from its young. So.it seizes the opportunity of getting a nutritious meal in the form of the young from a neighbouring hole. Why does it not dare go further? Because then it puts its own young at risk of being eaten by a neighbour. ■ Copyright—The Economist.