Animal Life

Life on oceanic islands

Flightless insects
Island insects risk being blown out to sea by the wind, so many have evolved into flightless forms. The strip-like wings of a fly found on Tristan da Cunha and Gough islands are useless for flight. Similar trends can be seen in the grasshoppers of the Galapagos Islands, and moths on other islands.

Dragons and giants
Oceanic islands have few reptiles, but those that evolve here become unusually large, perhaps because there is no competition from large mammals for space or food.

The Komodo dragon found only on Komodo Island and a few continental islands in the Sunda group in Indonesia is the world's largest lizard, growing to 2.5m long! The giant tortoises of Aldabra and the Galapagos Islands grow to incredible sizes.

Conservation concern
Island flora and fauna are particularly vulnerable to extinction, and animals brought on to islands by humans can wreak havoc. For example, because island plants have not developed defenses (like spines, thorns or a nasty taste) against large herbivores, they are easily wiped out when people bring in domestic stock like goats. Flightless and ground-nesting birds are defenceless against pet cats and the rats that come off ships.

Humans are affecting island wildlife in other ways. Oceanic islands are favourite holiday destinations and uncontrolled tourism can destroy wildlife habitats, especially along the coasts. Large areas of unique island vegetation have been cleared for pineapple plantations in Hawaii.
Iguana. / ©: WWF
Iguana.
© WWF
Komodo Dragon. / ©: WWF
Komodo Dragon.
© WWF

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