A creature initially mistaken for an extinct tortoise has turned out to be a giant bunny that had tiny ears and couldn鈥檛 hop.
The 5-million-year-old remains of Nuralagus rex were found on the Spanish island of Minorca by independent researcher Josep Quintana. At an estimated 12 kilograms, it was around 10 times the weight of wild Spanish rabbits today.
Quintana came across the first fossil in the early 1990s when he was 19. He initially thought it was part of an extinct Minorcan tortoise. Later, Meike K枚hler and Salvador Moya-Sola of the Autonomous University of Barcelona鈥檚 Catalan Institute of Paleontology identified it as a giant rabbit.
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Now the three have uncovered enough fossils to reconstruct the entire animal and name it. They say its closest relative was Alilepus, a now-extinct genus whose members were about a tenth the size of N. rex and lived in Eurasia and North America at the time.
Land bridge
Quintana says the ancestors of N. rex colonised Minorca 5.3 million years ago when sea levels in the Mediterranean dropped by about 1.5 kilometres, connecting the Balearic Islands to the mainland.
As sea levels rose again and cut Minorca off, N. rex evolved separately from Alilepus. It shared the island with tortoises, bats and a large dormouse species, and in the absence of predators chose life in the slow lane. 鈥淚f you don鈥檛 have natural enemies, why run?鈥� asks Quintana. Gradually, its legs grew shorter, its ears shrank and its spine lost the curvature that helps rabbits hop.
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