Washington, August 15 : Birds possessing brains larger than expected for their body size might have facilitated the evolutionary diversification of some avian lineages, say researchers.
Ecologist Daniel Sol of CREAF-Autonomous University of Barcelona, and evolutionary biologist Trevor Price of the University of Chicago came to this conclusion after analysing body size measures of 7,209 species, representing 75 per cent of all avian species.
Their analysis showed that avian families that had experienced the greatest diversification in body size tended to be those with brains larger than expected for their body size.
The Picidae (woodpeckers), Bucerotidae (hornbills), Psittacidae (parrots), Strigidae (owls), Menuridae (lyrebirds), and Corvidae (crows) were such bird species.
The study also indicated that the brain-diversification association was statistically independent of geographic range and species richness.
"The most likely alternative is that big brains enhance the rate of evolutionary diversification by facilitating changes in behaviour, which would place new selection pressures on populations and favour adaptive divergence," Daniel Sol says.
The researchers are of the view that in species with high cognitive styles, behaviour might be, along with environmental factors, a major driving force for evolution.
The study has been published in the journal The American Naturalist.