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 Living on the Edge
Wild goats and sheep may not seem too exciting at first glance. But wait
until you get to know them better: some wild goats can climb trees, and some
goats and sheep can walk along a ledge not much wider than a tightrope! With
their amazing climbing talent, spectacular spiraling horns,
and ability to live in some of the world's steepest, most forbidding habitats,
they are worthy of our attention and appreciation.
Sheep or Goat?
How can you tell if you're looking at a goat or a sheep? If a male has the
familiar beard, or goatee, then he's probably a goat; male sheep don't have
beards. Another hint is the horns: a male sheep's horns usually curl and a
goat's are straight. But, of course, there are exceptions. Male Barbary sheep
Ammotragus lervia look like a mixture of both: they have beards and
curled horns! And the scientific name for Himalayan tahrs—Hemitragus
jemlahicus—means "something like a goat."
Fancy Footwork
Surefooted sheep and goats walk on two toes—the third and fourth—on each
foot. Some have two or more vestigial
toes called dewclaws. The bottoms of their feet are very soft. This gives them
the ability to climb on rocks with a secure foothold. Markhors Capra
falconeri are known for their tree-climbing ability, and those living at
the San Diego Zoo's Wild
Animal Park have even been seen walking along the top of a chainlink fence,
which is only a half-inch (1.2 centimeters) wide! Ibex Capra sp. and
Barbary sheep can jump over 6 feet (1.8 meters) straight up from a standing
position.
Horns—the Biggest Size Wins
Both male and female goats and sheep have horns, but those of the males are
much larger. The horns are made of keratin,
like our fingernails, and they are permanent, growing throughout the animal's
lifetime. A growth ring is deposited each winter. By counting those rings, it's
possible to tell the animal's age. In contrast, deer antlers
are made of bone and are shed and regrown every year.
Rams and bucks (male sheep and goats) use their horns in head-butting clashes
that get more intense during the breeding season, in the fall for most species.
Younger rams and bucks are eager to try their skills and may pick more fights,
but robust older males with their bigger and stronger horns can win fairly
quickly. The winner usually breeds with all the females and fathers the young.
The rest of the males return to bachelor
herds or stay by themselves until the next breeding season. Then the battles
resume, and they get another chance to beat the former winner.
Unfortunately, some bucks, including the endangered
markhor and some of the wild sheep, are still highly prized as trophy animals.
Hunters often pay thousands of dollars to pursue and kill them for their
horns.
Keeping Together
Does and ewes (adult female goats and sheep) live in groups (herds and
flocks). Most females give birth to a single kid (baby goat) or lamb (baby
sheep) in the spring. Before giving birth, a doe or ewe looks for a quiet and
safe location. Once the baby is strong enough to follow its mother, the pair
joins other mothers and babies. The youngsters become independent quickly. An
ibex kid can jump on its first day of life, and it joins kid groups by the
fourth week. Even at an early age, lambs and kids are agile and alert. Although
they are weaned
by four to six months of age, they remain with their mothers for at least a
year.
Cud Is Good
All goats and sheep are primarily grazers
and ruminants—cud
chewers, that is. A four-chambered stomach contains fermenting bacteria
and protozoans that help break down the tough grasses and other plants these
animals eat. At both the San
Diego Zoo and the Wild Animal Park, the sheep and goats are offered Bermuda
grass, alfalfa and alfalfa pellets, and acacia browse.
While at rest, the animals bring food back up from the first stomach chamber and
chew it, grinding it with their cheek teeth. Then they swallow their food a
second time for more thorough digestion. |