EPOW - Ecology Picture of the Week

Leapin' Colobus!

Black-and-white Colobus (Colobus guereza), Family Cercopithecidae
Mt. Kenya, Kenya

Explanation:  It's not who you think.  This large primate is native to east Africa -- Tanzania, Kenya, and Uganda -- inhabiting dense forests and woodlands.  

They feed mainly on young leaves, and also fruits and seeds, and sometimes tree bark and even insects.  As fruit- and seed-eaters (frugivores and spermivores), they also play a key ecological role in the tropical forests as seed dispersal agents, helping to distribute shrubs and trees throughout their range.  

They are largely diurnal -- active during the daytime -- with their troops often moving among the tree subcanopies with wondrous leaps.  

The dominant male often has to provide aggressive postures
to thwart other guereza troops from intruding.
  

   
Guerezas have only four fingers, with the thumb much reduced.
Perhaps this aids their being able to quickly leap branch to branch. 

There are two species of colobus (the plural is colobi) in east Africa.  This one also goes by various names, including black-and-white colobus, guereza, mantled guereza, eastern black-and-white colobus, and Abyssinian black-and-white colobus (a taxonomic synonym to its scientific name Colobus guereza is Colobus abyssinicus).  In local Swahili it is called mbega.  It has eight subspecies, and is not threatened or endangered.  
    

The tail is spectacular, but why did it evolve this way?

Perhaps it serves as a social signaling device, or helps in leaping among the trees.