EPOW - Ecology Picture of the Week

Piebald Zebra

Plains (Burchell's) Zebra (Equus [burchelli] quagga, E. quagga burchelli), Family Equidae
Serengeti National Park, Tanzania

Explanation:  Strangeness strides here.  What is happening to this plains zebra in Serengeti National Park, Tanzania?  Are the stripes melting?  

At first I thought I was seeing sun glaring off the hide of this equid, but quickly realized that can't be.  There is very much a stripeless white patch on the hide of this bontequagga.  

Such coloration is uncommon but does occur in many animal species, including humans, and is given the specific name of piebaldism.  It is not albinism, and surely not melanism.  In fact it is caused by the local absence of melanocytes, the cells that produce melanin that colors the hair and skin.  

In this zebra, this is a nice natural experiment.  Zebras are thought to be primarily black, with white stripes, not the other way around.  But here, the piebald patch is white, with only hints of some remnant melanistic skin and hair.  

I also initially thought that I was looking at a more common cause of white patches on the backs of large mammals:

... yes, a hitchhiker -- above, a yellow-billed oxpecker enjoying a free ride across the savanna grassland ... or, below, red-billed oxpecker freeloaders on another zebra:

... because sometimes such riders will ... well, they will leave a calling card:

... such as has happened on this hapless Indian one-horned rhinoceros in Kaziranga National Park of northeast India.

But no, this too is not the case with the Piebald Zebra of the Serengeti.

This was the only zebra I've ever seen with this genetic quirk, in all the trips and travels I've done to a dozen or more sub-saharan African countries.