A powerful bite allowed a family of New World bats to expand their diet to hard fruits, driving an explosion in species number.
Elizabeth Dumont at the University of Massachusetts in Amherst, Liliana Dávalos at Stony Brook University in New York and their colleagues compared the diet, head shape and bite strength of the New World leaf-nosed bat family (Phyllostomidae, a range is pictured). This group comprises 180 species and has the most varied diet — ranging from blood to insects and fruit — of any mammalian family.
The authors found that, within a subfamily of fruit-eating bats, the animals' head shapes had undergone fewer changes after gaining a certain morphology that allowed for a strong bite. That evolutionary plateau was accompanied by an increase in the number of species, all of which can eat hard fruits such as figs.
Proc. R. Soc. B http://dx.doi.org/10.1098/rspb.2011.2005 (2011)