EPOW - Ecology Picture of the Week

The Sun Squirrel

Mutable Sun Squirrel (Heliosciurus mutabilis), Family Sciuridae
Njobvu, Malawi, Africa

Explanation:  Ah, the Squirrel that Loves the Sun.  This is a sun squirrel of southern Africa ... along the western shore of Lake Malawi, to be exact.  

Sun squirrels are the largest indigenous tree-dwelling squirrels of Africa.  That's saying a lot, as there are nearly 80 squirrel species just in this region of the continent.  This species grows to 48 cm (19 inches) long, including the tail.

Sun squirrels occur singly or in pairs, and, well, seem to enjoy the sun by basking along branches in the upper canopy of trees.  They are common.

This one of five species of genus Heliosciurus.  It is distributed patchily in southern Africa and occurs in various color forms (thus the species name "mutabilis," meaning mutable or changeable).  This variation is itself a hint that the high diversity of squirrel species in Africa has arisen by populations becoming isolated as climates have severed forest, woodland, and riverside habitats.  Isolated populations, in some cases, eventually developed into new species.   

According to Jonathan Kingdon (see Information, below), squirrels first invaded Africa less than 10 million years ago as ground-dwellers living in dry environments.  They then "radiated" or evolved in a wide array of ecological types, the tree-dwellers being the most recent.  

Sun squirrels of genus Heliosciurus are suspected to be carriers of disease in Africa.  
 

Information:
     Kingdon, J. 1989. Island Africa: the evolution of Africa's rare animals and plants. Princeton University Press, Princeton, N.J. 287 pp.