Extinct rabbit ‘didn’t hop and had no enemies’

The massive bunny lived three to five million years ago on the Spanish island of Minorca.

Updated: Mar 23, 2011, 10:15 AM IST

Washington: A massive bunny that lived three to five million years ago on the Spanish island of Minorca was so hefty that it had lost the ability to hop and had no enemies, according to a new study.

The new species, aptly dubbed the ‘Minorcan King of the Rabbits’ (Nuralagus rex), weighed in at 26.4 pounds — approximately six times the size of most rabbits today.

“N. rex was a very robust and peculiar rabbit. Surely he was a very calm and peaceful animal that moved with slow, but powerful, movements,” project leader Josep Quintana told Discovery News.

Quintana, a scientist at the Catalan Institute of Paleontology, and colleagues Meike Kohler and Salvador Moya-Sola believe the rabbit lost the ability to hop, because the long, springy spine typical of modern bunnies was replaced by a short, stiff backbone.

They think N. rex spent most of its days peacefully digging, searching for roots and tubers to eat.

“The ancestors of N. rex arrived at Minorca during the Messinian crisis 5.3 million years ago. During this geological time, the Mediterranean Sea dried up and the Balearic islands connected with the surrounding mainland (of Europe and Africa), so the proto-Nuralagus rex arrived walking to Minorca,” said Quintana.

Over time, it grew to become 10 times the size of its now-extinct mainland cousin. Other inhabitants of the island at the time included a bat, a large dormouse and a giant tortoise.

With no need for defence, the rabbit lost visual and hearing acuity. Its eye socket reduced in size over time, as did its ears.

The researchers believe the rabbit reached its gigantic size because of the ‘island effect’, which can cause small animals to evolve into big ones because of a lack of predators.

“There is an underlying assumption that rabbits appeared some 40 million years ago and have been perfectly happy to stay just about the same,” Brian Kraatz, an assistant professor in the Department of Anatomy at the College of Osteopathic Medicine of the Pacific, told the Discovery News.

“This new species is interesting in that it`s quite different from what we know of living or fossil rabbits. Aside from its incredibly large size, its hind legs are rather short, not so good for hopping,” he added.

The discovery has been described in a Journal of Vertebrate Paleontology.