EPOW - Ecology Picture of the Week

Sharing the Waterhole

Plains (Burchell's) Zebra (Equus [burchelli] quagga, E. quagga burchelli), Family Equidae
Olive Baboon (Papio anubis), Family Cercopithecidae
Lake Nakuru, Kenya

Explanation:  Here on the edge of wildlife-diverse Lake Nakuru in southwest Kenya, eastern Africa, we find a most interesting aggregation of two species:  plains zebras and olive baboons ... each awaiting their turn to dip into a tiny waterhole to quench their thirst.

First, I have to marvel at these critters' patience and tolerance, as they queue up to partake in this resource.  But, as often happens in nature, "big goes first," with the equids (zebras) first in line.  

So why do you think they are huddled here at a small pit in the ground, when in the background there is an entire lake at their disposal?  I don't know.  But I speculate that perhaps the water in this hole is more tolerable, more desirable ... perhaps cleaner and not tainted by algae or other growths ... or perhaps it contains some vital minerals that lake water does not.  

Perhaps on this last point, such attraction to spots serves a function similar to mineral licks that animals sometimes do, when they lick up and ingest particle of soil and clay that contain key elements for sustaining their health, as we have seen in previous EPOW episodes.  

And, aha, two more things in this scene relate to other ecological relationships.  Can you spot them in the above scene?

One is the bare ground surrounding the waterhole.  Bare ground can be a very important resource for animals, especially ungulates like zebras, to engage in dusting behavior, that is, simply rolling in the dirt to rid oneself of lice, ticks, and other ectoparasites.  We explored such resources in previous episodes.  And bare ground created by one species, such as zebras, can become useful dusting sites for other species, such as birds, as well.   

And the other ecological relationship visible in the above image is that trail in the foreground created by the zebras and likely other species.  Here, in open ground, it is not so much a resource, but in more woodland and forest situations, game trails created by large animals can be very key for smaller animals who use those cleared pathways to access key resources ... such as a water source.

So there you have it:  there is more to this casual aggregation than first meets the casual eye!