Toque Macaques feeding in water grass, Bundula, Sri Lanka

The toque macaque (Macaca sinica) is a reddish-brown-coloured Old World monkey endemic to Sri Lanka, where it is locally known as the "rilewa" or "rilawa" (Sinhala රිළවා), (hence "rillow" in the Oxford English Dictionary). It is named for the toque-shaped whorl of hair on its head, rather like the bonnet of the related bonnet macaque.