I recalled hearing about the discovery of a “hobbit” skull a few years ago and about the debate of whether or not is was a new species of hominid or not.
(the hobbit skull is on the left...)
Well, the debate goes and there are many arguments which you can read about here.
But the topic I want to bring up is the biological phenomenon by which the size of animals isolated on an island shrinks dramatically over time. That’s the story of our hobbit friend whose undersized bones were found inside Liang Bua cave on the Indonesian island of Flores. An island that they shared with Stegodon pygmy elephants, much to the misfortune of the pygmy elephant as “hobbits” ate a lot of them.
dwarf elephant
How does this phenomenon occur? Well I am glad you asked because I have an explanation (well wikipedia helped):
It is because of Insular dwarfism, a form of Phyletic dwarfism, is the process and condition of the reduction in size of large animals – almost always mammals – when their gene pool is limited to a very small environment, primarily islands.
This effect has made itself manifest many times throughout natural history, including dinosaurs and modern animals such as elephants and human beings.
There are several proposed explanations for the mechanism which produces such dwarfism, which are often considered likely to be co-contributing factors, including an evolved gene-encoded response to environmental stress, as well as a selective process where only the smaller of the animals trapped on the island survive, as food declines to a borderline level. The smaller animals need fewer resources, and so are more likely to get past the break-point where population decline allows food sources to replenish enough for the survivors to flourish.
It just proves that size isn’t everything…
getting older & wiser... 
did you know though that traditional small animals actually become larger on small islands, such as rodents.