A rare courtship between a female Grizzled Giant Squirrel and a male ‘hybrid’ of Malabar Giant Squirrel and Grizzled Giant Squirrel has been reported from the Chinnar Wildlife Sanctuary.
The unusual behaviour was spotted during a recent trek to Koottar in the sanctuary, the only natural habitat of Grizzled Giant Squirrel ( Ratufa macroura ) in the State, by Sujith V. Gopalan, project associate, Kerala State Biodiversity Board, and Suresh V. Kurup, a wildlife photographer from the city.
“We noticed some vigorous movement on a tree. We were quick to identify the smaller one as a Grizzled Giant Squirrel. But the larger one confused us as it was not similar to Malabar Giant Squirrel or Grizzled Giant Squirrel. It was larger compared to both the species, with a very distinct colour,” Mr. Gopalan said. It had characters of both the species. An examination of the photographs confirmed that the courtship was between a female Grizzled Giant Squirrel and a male hybrid of Malabar Giant Squirrel and Grizzled Giant Squirrel.
Rare
“Cases like these are least studied for extremely rare occurrence,” the KSBB project associate said, adding this small incident in the life of giant squirrels of Chinnar would help in evolutionary studies in hybridisation.
Though hybrids have been recorded across taxa, only a few had been recorded in higher vertebrates.
Mule (sterile hybrid of a male donkey and a female horse) and liger (sterile hybrid between male lion and female tiger) are known for the fact that they are facilitated by humans.
Evolutionary outcome
Natural hybridisation leading to speciation in mammals such as Caribbean species of bat ( Artibeus schwartzi ) is rare. Natural hybridisation leading to speciation can have a variety of evolutionary outcomes.
“It is more important to note that a hybrid is in the process to generate its offspring rather than identifying a hybrid of the Malabar Giant Squirrel and the Grizzled Giant Squirrel,” Mr. Gopalan said.
According to him, if the hybrid turns to be fertile it will take a serious churn in the genetics of giant squirrels of Chinnar with a definitely uncertain future for the parental population. A systematic five-day survey earlier this year recorded 68 Grizzled Giant Squirrels in the sanctuary.
