The rabbit, an animal often associated with this time of year (Easter), is not a rodent, although many members of the public think this chisel-toothed animal is. After all, rodents have chisel-teeth too. However, whilst both rodents and rabbits tend to be small, often burrow dwellers and herbivorous with ever-growing front incisors, there are notable differences. For example, rabbits, hares and pikas (referred to as lagomorphs), have two pairs of upper chisel-like incisors whilst rodents only have one pair. Rabbits also differ from rodents in that they have short tails, long ears that also help them to radiate excess heat as well as listen out for predators and long hind legs adapted to a jumping gait.
Although, they are related to rodents, where rabbits and their kin fit into the history of mammal evolution remains hotly debated. The earliest fossils associated with these types of creatures date back to just a few million years after the extinction of the dinosaurs. Whilst only two families of rabbits survive today – the Leporidae (hares and rabbits) and the Ochotonidae (pikas), in the past they were much more diverse and these animals have an extensive fossil record.
Some prehistoric rabbits were giants such as Nuralagus rex which inhabited the Spanish island of Menorca until about 3 million years ago. This giant bunny is estimated to have weighed more than twenty kilograms and it was so large and heavy it probably lost the ability to hop.
A Comparison of the Giant Pliocene Rabbit Nuralagus rex with a Pet Rabbit
Picture Credit: Mary Persis Williams
Rabbits might be associated with this time of year (Easter), but to a vertebrate palaeontologist, these lagomorphs have a long and diverse fossil record and some ancient rabbits were giants.