An enormous bunny that lived three to five million years ago was so hefty -- six times the size of most rabbits today -- that it didn't hop and had no enemies. 
 
 The new species, dubbed the Minorcan King of the Rabbits (Nuralagus rex), weighed in at over 26.4 pounds and lived on the small island of Minorca. 
 
 "N. rex was a very robust and peculiar rabbit," project leader Josep Quintana told Discovery News. "Surely he was a very calm and peaceful animal that moved with slow, but powerful, movements." 
 
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 Quintana, a scientist at the Catalan Institute of Paleontology, and colleagues Meike Kohler and Salvador Moya-Sola describe the giant fossil rabbit in a Journal of Vertebrate Paleontology paper. They believe the rabbit lost the ability to hop, because the long, springy spine typical of modern bunnies was replaced by a short, stiff backbone. 
 
 The researchers 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," Quintana said. "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." 
 
 When the seawater returned and Minorca returned to its island status, the rabbit found itself with no predators. 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. 
 
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 With no need for defense, the rabbit lost visual and hearing acuity. Its eye socket reduced in size over time, as did its ears. 
 
 The changes, especially the increase in body size, add to the growing evidence for what's known as "the island rule." Simply put, this states that when on islands, big animals often tend to become smaller and small animals frequently tend to grow larger. 
 
 On the small side of that equation, other islands have been home to tiny elephants and even, in the case of Homo floresiensis, tiny humans. 
 
 "It is as if nature experimented with form and function, not without a wicked sense of humor," Lucja Fostowicz-Frelik, an American Museum of Natural History paleontologist, told Discovery News. 
 
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 Fostowicz-Frelik continued that the newly found rabbit "is just another manifestation of the island rule ... We know that their closest relations, rodents, did produce some gigantic forms, not necessarily on islands, which averaged several hundred kilos. Now we see that the lagomorphs (the animal order that includes rabbits, hares and pikas) did not escape the trend." 
 
 Brian Kraatz, an assistant professor in the Department of Anatomy at the College of Osteopathic Medicine of the Pacific, agrees. 
 
 "There is an underlying assumption that rabbits appeared some 40 million years ago and have been perfectly happy to stay just about the same," Kraatz told 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, "It's unclear whether their feet would have been decent good luck charms." 
 
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 Bad luck affected the rabbit when a climate cooling likely ruined comfortable living conditions for the species on its island. The researchers suspect this climate change led to the rabbit's extinction. 
 
 Through the recent science, however, it lives on, with more studies of its fossils in the works. Quintana also hopes this rabbit "king" will become a popular mascot for the island. 
 
 He explained, "I would like to use N. rex to lure students and visitors to Minorca!" ||||| A reconstruction of Nuralagus rex in a landscape with a living European rabbit Oryctolagus cuniculus in the foreground for comparison. 
 
 Just in time for Easter, the skeleton of a giant rabbit has been discovered, one that was once about six times the size of today's bunnies. 
 
 The fossils of the giant were discovered on the island of Minorca off the coast of Spain, a fact reflected in the rabbit's scientific name, Nuralagus rex, "the Minorcan king of the rabbits." 
 
 "I needed four years to recover a good sample of N. rex bones because they were in very hard red stone," paleontologist Josep Quintana at the Catalan Institute of Paleontology in Barcelona, Spain, told LiveScience. "To pull the bones out from the matrix, it was necessary to use some hundreds of liters of acetic acid, a very concentrated vinegar — very hard and patient work! But it was worthwhile, of course." 
 
 When the bunny lived approximately 3 million to 5 million years ago, it weighed about 26 pounds (12 kilograms), about six times the size of the living European rabbit (Oryctolagus cuniculus). [Fossils of Oldest Rabbit Relative Found] 
 
 The fact that it got so big on Minorca seems to follow the so-called "island rule." On islands, big animals often get smaller, due to limited food, while small animals often get bigger, due to lack of predators. 
 
 Foot bones of Nuralagus rex, the giant rabbit whose remains were discovered on the island of Minorca. Credit: Josep Quintana. 
 
 "For most of their over 40-million-year history, members of the rabbit family have fit well within the size range exhibited by relatively well-known modern members of the family. Now, discoveries on Minorca have added a giant to the mix, a 25-pound, short-legged rabbit," said rabbit researcher Mary Dawson at the Carnegie Museum of Natural History in Pittsburgh, who did not take part in this study. 
 
 As big as it was, N. rex might have been easy prey today — it lost the ability to hop. The long, springy spine of a typical modern rabbit was lost in N. rex, replaced by a short, stiff spine that would make leaping difficult. 
 
 "I think thatN. rex would be a rather clumsy rabbit walking — imagine a beaver out of water," Quintana said. 
 
 The giant probably also had poor hearing and vision, with relatively small eye sockets and internal ear parts. Its senses likely deteriorated for the same reason it got so large — it did not have predators to worry about. As such, it probably lacked another key trait often associated with rabbits — long ears. The bunny likely sported relatively small ears for its size. 
 
 Based on the rabbit's curved claws, the researchers suspect the animal was most probably a digger that lived on roots and tubers it unearthed. Its neighbors included bats, large dormice and giant tortoises. 
 
 Quintana proposes that this newfound giant might make a good mascot for the island. "I would like to use N. rex to lure students and visitors to Minorca," he said. 
 
 The scientists detailed their findings online today (March 21) in the Journal of Vertebrate Paleontology.
– On the Spanish island of Minorca up to 5 million years ago, the rabbit was king. Researchers there have discovered fossils belonging to the biggest-ever member of the bunny family, LiveScience reports. Nuralagus rex, weighing in at some 26 pounds—about six times the size of modern rabbits—had largely lost the ability to hop, and had relatively small ears, researchers say. Scientists believe the rabbit reached its gargantuan 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," a researcher tells Discovery. "This new species is interesting in that it's quite different from what we know of living or fossil rabbits."