The Zoological Society of London (ZSL) has unveiled the secrets of giant rodents which were once found on eastern Caribbean islands such as St Lucia, Guadeloupe, St Kitts and Nevis.
ZSL and the Natural History Museum (NHM) reconstructed the astonishing history of the Caribbean rice rats. Looking at the DNA of rice rats from 10 Caribbean islands they discovered an unexpectedly high amount of diversity in the population. 
When Caribbean rice rats went extinct one of the largest mammal extinction events in the past thousand years took place. It rivalled better known extinctions such as that of the thylacine a mammal from Australia.
In their native land this species was the only native land mammal. They could grow to be as big as a cat. By the 20th century the species was sent extinct. This followed the arrival of European colonists arriving on the islands. Now they are only seen as bones or museum specimens.
Co-author of the study and a fellow at ZSL, Dr Samuel Turvey said, “We might not expect rodents, which are widespread, fast-breeding and adaptable, to be vulnerable to extinction. However, whilst rice rats were once found on many islands in the Caribbean and were even more diverse than we originally thought, they were not able to survive the threats caused by human activity. Their complete disappearance highlights the vulnerability of many species that have evolved on islands, and demonstrates that huge amounts of biodiversity are potentially at risk of human-caused extinction.”
Dr Selina Brace, the lead author of the paper and a researcher from the NHM added, “Hot climates damage ancient DNA, so working with extinct Caribbean rodent samples was incredibly challenging. Despite the pain it was worth it when we found such an unexpected level of diversity in this group, meaning we could highlight this forgotten radiation of extinct rodents.”
For those looking to read the full research paper it can be accessed in Proceedings of the Royal Society B.
