Weird news of the week: Experts predict a future of rats the size of sheep

Rats could fill the avoid of extinct larger mammals, according to a geologist's theory.

10:23 06 February 2014

Rats are well known for their survival instincts, making it through the toughest of conditions in one piece. Now experts have warned that we may be seeing them evolve to the size of sheep.

As larger mammals become extinct, it's thought that not only will the rat remain but that it will also move up the food chain and take advantage of the vacant slot.

The world's current biggest known rodent is the capybara, which can weigh in at a whopping 80kg (12st).

Dr Jan Zalasiewicz, from the University of Leicester was quoted by Metro: "Animals will evolve, over time, into whatever designs will enable them to survive and to produce offspring.

The geologist continued: "Given enough time, rats could probably grow to be at least as large as the capybara, the world’s largest rodent, that lives today [and] can reach 80kg.

"If the ecospace was sufficiently empty, then they could get larger still."

Dr Zalasiewicz pointed to 'rat islands' as proof of the theory. A 'rat island' is an isolated region in which rats were introduced by humans. They then took over the local wildlife to become the dominant species - something which could happen in wider society.

"So there will be future thin rats, future fat rats, slow and heavy rats, fast and ferocious rats, probably future aquatic rats – the list goes on."

Huge rodents are nothing new. Three million years ago, the Josephoartegasia monesi roamed the land weighing over a ton and boasting a frame larger than that of an adult bull.