(via Favorite @fieldnotesbrand notebooks ever. So #orange. #EEE… | Flickr)

Guenons are Old World monkeys found in sub-Saharan Africa. Different guenon species exhibit incredible range of phenotypic features from differently shaped of ear tufts to differently coloured nose spots. It is thought that this great diversity has evolved to prevent interbreeding between different species (habitats of different guenon species often overlap geographically), which could lead to less fit offsprings.  

Illustration by Jonathan Kingdon