Zebra
Zebras, horses and wild asses are all equids, long-lived
animals that move quickly for their large size and have teeth built
for grinding and cropping grass. Zebras have horselike bodies, but
their manes are made of short, erect hair, their tails are tufted
at the tip and their coats are striped.
Three species of zebra still occur in Africa, two of which are
found in East Africa. The most numerous and widespread species in
the east is Burchell's, also known as the common or plains zebra.
The other is Grevy's zebra, named for Jules Grevy, a president of
France in the 1880s who received one from Abyssinia as a gift, and
now found mostly in northern Kenya. (The third species, Equus zebra,
is the mountain zebra, found in southern and southwestern Africa.)
Physical Characteristic
The long-legged Grevy's zebra, the biggest of the wild equids, is
taller and heavier than the Burchell's, with a massive head and large
ears.
Zebras have shiny coats that dissipate over 70 percent of incoming
heat, and some scientists believe the stripes help the animals withstand
intense solar radiation. The black and white stripes are a form
of camouflage called disruptive coloration that breaks up the outline
of the body. Although the pattern is visible during daytime, at
dawn or in the evening when their predators are most active, zebras
look indistinct and may confuse predators by distorting true distance.
The stripes on Grevy's zebras are more numerous and narrow than
those of the plains zebra and do not extend to the belly. In all
zebra species, the stripes on the forequarters form a triangular
pattern; Grevy's have a similar pattern on the hindquarters, while
others have a slanted or horizontal pattern.
Habitat
Burchell's zebras inhabit savannas, from treeless
grasslands to open woodlands; they sometimes occur in tens of thousands
in migratory herds on the Serengeti plains. Grevy's zebras are now
mainly restricted to parts of northern Kenya. Although they are adapted
to semi-arid conditions and require less water than other zebra species,
these zebras compete with domestic livestock for water and have suffered
heavy poaching for their meat and skins.
Behavior
Family groups are stable members maintaining strong bonds
over many years. Mutual grooming, where zebras stand together and
nibble the hair on each other's neck and back, helps develop and preserve
these bonds. Family members look out for one another if one becomes
separated from the rest, the others search for it. The group adjusts
its traveling pace to accommodate the old and the weak.
The females within a family observe a strict hierarchical system.
A dominant mare always leads the group, while others follow her
in single file, each with their foals directly behind them. The
lowest- ranking mare is the last in line. Although the stallion
is the dominant member of the family, he operates outside the system
and has no special place in the line.
Diet
Zebras are avid grazers. Both Burchell's and Grevy's zebras
are in constant search of green pastures. In the dry season, they
can live on coarse, dry grass only if they are within a short distance
(usually no farther than 20 miles away) of water holes.
Caring for the Young
When a foal is born the mother keeps all other zebras
(even the members of her family) away from it for 2 or 3 days, until
it learns to recognize her by sight, voice and smell.
While all foals have a close association with their mothers, the
male foals are also close to their fathers. They leave their group
on their own accord between the ages of 1 and 4 years to join an
all-male bachelor group until they are strong enough to head a family.
Predators
Zebras are important prey for lions and hyenas, and to
a lesser extent for hunting dogs, leopards and cheetahs. When a family
group is attacked, the members form a semicircle, face the predator
and watch it, ready to bite or strike should the attack continue.
If one of the family is injured the rest will often encircle it to
protect it from further attack.
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