Dwarfism is a condition in which either the limbs are disproportionately short relative to the body, or the whole body is in proportion but is smaller than usual. It can be caused by a number of genetic mutations, and is relatively common in humans. It has also been selectively bred in many domestic animals, such as dogs, cats and cattle. However, dwarfism in the wild is incredibly rare. 

"If you think about it, most animals, especially mammals, are either predators or prey. If you are either and are born with short limbs you would be at a very big disadvantage," Prithiviraj Fernando of the Centre for Conservation and Research, and one of the authors of the paper, told mongabay.com. "A dwarf prey animal is very likely to be caught by a predator and similarly, a dwarf predator would find it very difficult to catch prey. So such individuals are very unlikely to survive in the wild. Elephants in Sri Lanka are unique (together with those in Borneo) in that they have no predators. So he was very lucky that he was born here!"