In Gujaret, central India, fossil hunters have unearthed small ankle bones from a 53 million-year-old lagomorph. Lagomorpha is an order comprising of rabbits, hares and pikas.
This study is significant because it shows that lagomorphs had already begun to diversify during the Eocene Epoch. This diversity in mammals has been attributed by scientists to the global warming that had occurred 2 million years earlier.
For more info: http://news.bbc.co.uk/1/hi/sci/tech/7253518.stm