BIRTH-RATE AND MORTALITY-RATE OF INFANTS WITH CONGENITAL-MALFORMATIONS OF THE LIMBS IN THE AWAJISHIMA FREE-RANGING GROUP OF JAPANESE MONKEYS (MACACA-FUSCATA)

The birth rate and mortality rate of infants with congenital malformat ions of the limbs were examined in the Awajishima free-ranging group o f Japanese macaques (Macaca fuscata). Of the 606 infants born between 1978 and 1995, 86 (14.2%) were malformed. The male-female ratio did no t differ between malformed and normal infants. Most kin-groups include d females who gave birth to malformed infants at least once. The morta lity rate within the first year after birth for malformed infants (28. 2%) was significantly higher than that for normal infants (10.0%). How ever, this indicates that more than 70% of malformed infants were able to survive for the first year of life, even though they were unable t o cling to their mother's ventrum due to their limb deformities. This finding indicates that maternal care-taking is sufficient to enable ma lformed infants to survive during the early stages of development and that clinging by the infant is not necessary for the display of matern al care. (C) 1997 Wiley-Liss, Inc.