快猫短视频

Madison

PROVIDING milk for newborns is the exclusive role of mothers. So the
discovery that prolactin, a hormone associated with milk production in females,
increases in male tamarin monkeys before their young are born has surprised
biologists.

Prolactin鈥檚 main function is to prepare the mammary glands of females for
milk production: levels of the hormone rise in females during late pregnancy.
But researchers at the University of Wisconsin-Madison and the Wisconsin
Regional Primate Research Center found that prolactin levels in urine samples
from male cotton-top tamarins began to rise at least two weeks before their
mates gave birth.

Levels were highest in the more experienced fathers鈥攖hose with the most
offspring鈥攂ut appeared to have little to do with the amount of contact
that the father subsequently had with the infant. 鈥淭he males with the most
experiences [of rearing young] have the highest prolactin levels, but
paradoxically often do little direct parental care,鈥� says Charles Snowdon, one
of the researchers.

The purpose of the hormone increase in males is a mystery. High prolactin
levels are known to be associated with stress in primates. However, levels of
cortisol鈥攁 hormone that rises with stress鈥攊n the male tamarin
monkeys remained unchanged while their prolactin levels went up. The researchers
speculate that prolactin may help the fathers tolerate the presence of
infants.