This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
The governments of Kenya and Ethiopia agreed last week to develop a new action plan to help protect the endangered Grevy's zebra (Equus grevyi), the rarest zebra species and the largest equid species on the planet. The previous five-year conservation strategy for the species expired last year.
Grevy's zebra populations have declined from an estimated 15,000 in the 1970s to about 2,400 today. Most of the animals live in Kenya; about 140 live in Ethiopia. The species has disappeared from much of its previous range, including Somalia, Djibouti, Eritrea and Sudan. The International Union for Conservation of Nature and Natural Resources calls the change "one of the most substantial reductions of range of any African mammal."
As with so many other African species, poaching is a large reason for the reduction. Zebra hides can fetch big bucks, and both zebra fat and bone marrow have purported medicinal values in some traditional Kenyan medicine practices.
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Other major factors in the species's decline have been habitat loss and competition for water and vegetation from agriculture and livestock. Habitat degradation and fragmentation often forces the animals to travel great distances to eat or drink. Although Grevy's zebras are adapted to arid conditions and can normally last up to five days without water, nursing females can only go a single day before their milk dries up. According to the Grevy's Zebra Trust, the increasing scarcity of water resources has caused a higher rate of foal mortality.
Diseases, including anthrax, have also hurt Grevy's zebra mortality, although research into how and why these diseases afflict the animals is still in its infancy, according to the Earthwatch Institute.
The two-day workshop to develop the new action plan was attended by government and conservation organizations as well as private landowners. The participants discussed cross-border cooperation, protecting water and pasture resources, controlling invasive species, development of new roads and oil pipelines into the zebras' habitats, and the growing human populations in the region. They did not announce a timeline for publishing the new plan, but the Kenya Wildlife Service (KWS) did say that the second census of Grevy's zebra populations will be conducted later this year. The first was taken in 2008 under the previous five-year plan.
Meanwhile, the KWS has uncovered another potential threat to Grevy's zebra populations: the males aren't as aggressive about finding mates as are the more common plains zebras (Equus quagga). Instead, the males wait for females to come to them. Because the two species' habitats overlap slightly, this apparently causes some breeding confusion: KWS has found 22 hybrid zebras in the overlapping territory.
Photo: Sergey Yeliseev via Flickr. Used under Creative Commons license