Multi-age Broods. Ignorance or Apathy?

John Waters (
Sun, 04 Aug 1996 09:51:34 +0100

Although humans and apes share many physiological and behavioural
characteristics, there are also many differences. One characteristic
which is peculiar to humans is the Multi-age Brood. In fact, the human
specie is the only mammal to rear multi-age broods to maturity. Apes by
contrast, have single age broods.

A multi-age brood is defined as a brood of mammal young, of different
ages, all of whom are in their preweaning stage of development. The age
difference must be at least one gestation period.

Apes generally rear one infant at a time. They can give birth to twins,
but these do not generally survive in the wild, due to feeding and
transportation problems. As a 'norm', apes wean off their previous born
infant at least three months before the next infant is born. The average
birth interval for chimpanzee infants born in the wild is five and a
half years.

By contrast, in modern industrial societies, human mothers may give
birth every year. As the age of weaning for a human infant is about
seven years of age, a human mother can concurrently rear six infants at

It is curious that this multi-age brood characteristic is not mentioned
in any encyclopedia, or any reference work on primates. Is this due to
ignorance or apathy?

John Waters