Copyright 2005, all rights reserved
Philandering life mates
Which animals mate for life? (Jen, New York, New York)
The gray wolf mates for life. Pups are born in the spring. Through the
summer while the pups grow in ability, the adults hunt singly. Each autumn, the
pups join the hunting pack and both parents teach them to hunt and kill prey. A
family group of about five members (the parents and various offspring) stay
together and form a hunting pack. [Gary Kramer, US Fish and Wildlife Service]
A: Gibbon apes, wolves, termites, coyotes, barn owls,
beavers, bald eagles, golden eagles, condors, swans, brolga cranes, French angel
fish, sandhill cranes, pigeons, prions (a seabird), red-tailed hawks,
anglerfish, ospreys, prairie voles (a rodent), and black vultures ó are a few
that mate for life.
Of course, it depends on what you mean by "mate for life."
These creatures do mate for life in the social sense of living together in pairs
but they rarely stay strictly faithful. About 90 percent of the 9,700 bird
species pair, mate, and raise chicks together ó some returning together to the
same nest site year after year. Males, however, often raise other malesí
offspring unknowingly. DNA testing reveals that the social-pair male did not
father 10, 20, and sometimes 40 percent of the chicks.
Black vultures, though, discourage infidelity. All nearby
vultures attack any vulture caught philandering.
Only about 3 percent of the 4,000 mammal species are
monogamous (and Homo sapiens isnít one of them). Beavers, otters, bats,
wolves, some foxes, a few hoofed animals, and some primates live together in
social pairs but dally sexually much as birds do.
Wolves, for example, are generally monogamous but also breed
polygamously if the male is unrelated to the female and prey is plentiful.
Moreover, they sometimes have more than one mate in a lifetime, says
Dan Stahler, biologist at the Yellowstone Gray Wolf Restoration Program run
by the National Park Service. This happens "if one mate dies, gets kicked out of
the pack, or is physically unable to breed due to injury, illness, etc."
One species is absolutely monogamous. In the black darkness of
the deep sea, the tiny male anglerfish (perhaps one tenth the femaleís size)
detects and follows the scent trail of a female of his own species. Once found,
he bites his chosen one and hangs on. His skin fuses to hers, their bodies grow
together (he gets his food through a common blood supply and becomes essentially
a sperm producing organ). They mate for life ó a short life for the male.
J. Young and Zuoxin Wang (2004) The Neurobiology of the Pair Bond. Nature
National Geographic News: Lovebirds and love darts
University of Washington: Deflating the myth of monogamy by David P. Barash
(Answered Feb. 25, 2005)