Saturday, 19 January 2013

Species Spotlight ... The Grevy's Zebra

The Grévy's zebra (pronounced Grey) was first described by French naturalist Emile Oustalet in 1882. He named it after Jules Grevy, then the President of France, who, in the 1880s, was given one by the government of Abyssinia.

As with all zebra species, the Grevy's zebra's pelage has a black and white striping pattern. The stripes are narrow and close-set, being broader on the neck, and they extend to the hooves. The belly and the area around the base of the tail lack stripes which is unique to the Grevy's zebra. Foals are born with brown and white striping, with the brown stripes darkening as they grow older. The stripes of the zebra may serve to make it look bigger than it actually is or disrupt its outline. It appears that a stationary zebra can be inconspicuous at night or in shade. Its muzzle is ash-grey to black in color with the lips having whiskers. The mane is tall and erect; juveniles have a mane that extends to the length of the back and shortens as they reach adulthood.

The Grévy’s zebra largely inhabits northern Kenya and surrounding territories. Grévy's zebras rely on grasses, legumes and browse for nutrition. They commonly browse when grasses are not plentiful. Grevy's zebras can survive up to five days without water, but will drink daily when it is plentiful.  They often migrate to better watered highlands during the dry season. During droughts, the zebras will dig water holes and defend them. Grévy's zebras are preyed on by lions, cheetah, wild dogs and cheetahs.

They mostly live in territories during the wet seasons but some may stay in them year round if there's enough water left. Stallions that are unable to establish territories are free-ranging and are known as bachelors. Females, young and non-territorial males wander through large home ranges. The females will wander from territory to territory preferring the ones with the highest-quality food and water sources. Up to nine males may compete for a female outside of a territory.

Grévy's zebras can mate and give birth year-round, but most mating takes place in the early rainy seasons and births mostly take place in August or September after the long rains. An  mare may visit though as many as four territories a day and will mate with the stallions in them. Among territorial stallions, the most dominant ones control territories near water sources, which mostly attract mares with dependant foals, while more subordinate stallions control territories away from water with greater amounts of vegetation, which mostly attract mares without dependant foals. The resident stallions of territories will try to subdue the entering mares with dominance rituals and then continue with courtship and copulation.

The Grévy's zebra is considered endangered. Its population was estimated to be 15,000 in the 1970s and by the early 21st century the population was lower than 3,500, a 75% decline. It is estimated that there are less than 2,500 Grévy's zebras still living in the wild. There are also an estimated 600 Grévy's zebras in captivity. The Grévy's zebra population trend is considered stable as of 2008.
The Grévy's zebra is legally protected in Ethiopia. In Kenya it is protected by the hunting ban of 1977. In the past, Grévy's zebras were threatened mainly by hunting for their skins which fetched a high price on the world market. However hunting has declined and the main threat to the zebra is habitat loss and competition with livestock. Cattle gather around watering holes and the Grévy's zebras are fenced from those areas.

You can join us as we visit Kenya to see the Grevy’s Zebra in the Samburu National Reserve.