Putative hybrids between Indian giant squirrels (Ratufa indica) and grizzled giant squirrels (Ratufa macroura): a case study from the Western Ghats, India.

Abstract

Natural hybridization, long considered insignificant, is now recognized as one of the major driving forces for the diversification of vertebrate groups. It often occurs when previously allopatric species are forced into sympatry due to anthropogenic or natural causes. The impacts of hybridization on many rare and threatened animal groups are not clearly understood. We present here a detailed account of the possible hybridization between two species of oriental giant squirrels endemic to the Indian Sub-continent; the Indian giant squirrel (Ratufa indica) and the grizzled giant squirrel (Ratufa macroura) from the Western Ghats, India. A total of eleven putative hybrids could be recorded from the Chinnar Wildlife Sanctuary in Kerala. We present here the conclusive evidence for reproductive viability among the putative hybrids. The distribution of putative hybrids in the wildlife sanctuary is recorded, and the major factors contributing to the hybridization event are discussed.