Friday, August 17, 2018

Burchell's Zebra

There are three species of zebra: (1) the plains zebra; (2) the mountain zebra; and (3) the Grevy zebra. 

There are six subspecies of the plains zebra (not including the Quagga, which is extinct), including: (a) Burchell's zebra; (b) Grant's zebra; (c) Selous' zebra; (d) Maneless zebra; (e) Chapman's zebra; and (f) Crawshay's zebra. However, a 2018 DNA study questions the subspecies classifications. The subspecies classifications are all based on differences in striping and it is argued that the striping reflects a north to south genetic continuum. All zebras have black and white stripes and dark muzzles and no two look exactly alike. All have vertical stripes on the forepart of the body and then tend toward horizontal strips on the hindquarters. Northern populations of plains zebra (starting in Uganda) have narrower and more defined stripes. Southern populations of plains zebra have lesser, but varied amounts of striping on the underparts, the legs and the hindquarters. The southern populations also have brown "shadow" stripes between the black and white coloring. Embryological evidence suggests that the zebra's background color is dark and the white is an addition. 
This young zebra in Hwange NP, Zimbabwe has light shadow strips on the hindquarters and stripes going all the way down its legs. The black stripes are all pretty well defined. 
Also in Hwange NP. The shadow stripes are very light, although part of it is the lighting. 
Another zebra in Hwange. Striping going down most of the legs and light shadow stripes. 
I believe this may be the same zebra and the shadow stripes stand out a little better. 
Burchell's zebra are striped on the head, neck and flanks and sparsely down the upper limbs, fading to white. The Burchell's range was north of the Orange River in South Africa, extending northwest from southern Botswana to Etosha NP and the Kaokoveld in Namibia and southeast to Swaziland and the Kwazulu Natal. It is now extinct in the middle of the range and found in the northwestern and southeastern portions of that range. 
Zebra in the Okavanga Delta of Botswana. Stripes down the legs and shadow stripes on the hindquarters and back leg. 
Okavanga Delta zebras. Note that they have a little bit more of a brown background color, but still have a fair amount of striping down the legs. 
Okavanga Delta. Shadow stripes are weak, but could be the lighting. 
Now we get to Etosha NP in Namibia, further south, and the brown background gets greater, there is more white and less stripe on the legs and the shadow stripes appear darker or more pronounced. 

Another Etosha zebra with significant brown background and shadow stripes. 
These zebras are in the far eastern part of Etosha, at Kalkeheuwel waterhole. More signficant shadow striping, less on the legs and more brown background than the Hwange and Okavanga Delta zebras. 

1 comment:

  1. Remember your days of ignorance when you thought a zebra was a zebra? Nature's variety is amazing.