Islands are often isolated, creating unique, somewhat specialized fauna, as notably terrestrial species ar stuck and adapt separately. Special conditions can include the absence or inescapability of predators, scarcity of partners and harsh conditions such as weather or volcanic activity, which also creates new islands, as in the Galapagos. Even tiny islands also may have unique populations, even large ones like Madagascar entire types. Some species thrive surprisingly, like Komodo monitors on their Indonesian Island or even penguins on Antarctic ones.
—KGF Vissers