What is Island Gigantism?
Island gigantism is a biological phenomenon where animals that live on isolated islands tend to grow larger because of a lack of predators and competition which would otherwise be present on the mainland. Rather than being caused by a novel selection pressure, as is thought to be the case with the complementary phenomenon of island dwarfism, island gigantism is caused by the removal of constraints. The result are organisms that swell to ponderous sizes. Island gigantism is an apparent counterexample to Bergmann’s rule, a generality that states that animals that live near the equator tend to be smaller. Some islands with species that display island gigantism are located near the equator, but still have unusually large animals.
