The Island Rule is one of the best explanations scientists could give to the observable phenomenon that animals and humans have evolved (演变) depending on the resources available in their habitat (栖息地). Through time, scientists have noticed through fossil (化石) records that some large animals from mainland habitats have dwarf (矮小的) versions in bland habitats.

    A report from BBC described the existence of what scientists call “hobbit island” off a small island somewhere in Indonesia. It was given such a name because fossil records of tiny, humanlike creatures have been found in the region. What they called as “hobbits” or “Homo Floresiensis”, are only as tall as one meter and arc small versions of early human species with tinier brains.

    Though scientists cannot perfectly trace the origin of the “Homo Floriensis”, they believe that they arc human relatives, but it is the “island life” that has caused them to evolve as they have. Scientists have noticed through fossil records and existing organisms (有机体) today that it seems if large animals grow small in islands while small animals grow large in larger islands.

In theory, animal and human bodies have adjusted to the available food and fresh water in their habitats. Since there is no opportunity for them to leave their island, they might as well adapt.

    New York Magazine explained that islands usually have fewer predators (捕食者) than mainland ecosystems. However, it is the lack of resources that cause the death of many animals. As a means of natural adaptation, the bodies of these animals have evolved smaller than their ancestors, making their bodies require fewer resources.

    A report from Web Ecoist listed down a few examples of animals that have shrunk significantly compared with their ancestors. Some of these include the Bali tiger as small as leopards (豹).