Quintana, et al. 2011 introduced the world to the largest rabbit of all time, found on one of the smaller islands of Spain. The idea sounds funnier than it is, but after one looks into Foster's Rule, the so-called "Island Rule", it makes sense in a very interesting way and it can mean a few things:
1) Minorca was separated from continental Europe some time after rabbits had evolved into the recognizable fuzzy tailed garden thieves we know, love (or hate), and sometimes eat.
2) Minorca was a rabbit paradise. Barring any future discoveries of Nuralagus on continental Europe, we can assume that the animal evolved entirely on the island of Minorca and that it must have been a wonderful place for its ancestors to grow and prosper.
3) The unification of Majorca and Minorca caused the downfall of the rabbit Nuralagus by allowing a "cave goat" (Myotragus balearicus) to directly compete with Minorcan rabbits. This should, given adequate testing and sampling from the fossil record before, during, and after the transition provide a solid example of competition hypotheses and Foster's Rule as it relates to size due to competition for limited resources; Someone that is not me that wants to get on that, you are welcome for the idea.
It is interesting that competition with Myotragus may have ended the giant rabbit's rule. Quintana, et al. compare Myotragus and Nuralagus braincases, aerobic capacities, and locomotory characteristics to explain what happens to insular endemic species as they evolve in comparison to their continental cousins. Despite one of these taxa possibly out-competing the other and very different lineages, they had similar evolutionary patterns and morphological traits, relatively speaking.