Island gigantism is a biological phenomenon by which the size of animals isolated on an island increases dramatically over generations. It is a form of natural selection in which bigger size provides a survival advantage (see Bergmann's Rule). Large size in herbivores usually makes it harder to escape or hide from predators, but on islands, these are often lacking. Thus, island gigantism is not an evolutionary trend due to fundamentally new parameters determining fitness (as in island dwarfing), but rather, the removal of constraints. With the arrival of humans and associated predators (dogs, cats, rats, pigs), many giant island endemics have become extinct. In zoology, Bergmanns Rule is a principle that correlates environmental temperature with body mass in warm-blooded animals. ... Island dwarfing is a biological phenomenon by which the size of animals isolated on an island shrinks dramatically over generations. ... In biology and ecology, extinction is the ceasing of existence of a species or group of species. ...

Examples of island gigantism include:

• Mammals
  • Extinct giant rabbits, shrews and dormouse from Mediterranean islands
  • Flores Giant Rats
  • Giant hutias from the West Indies
  • the extinct giant lemur genera Archaeoindris, Palaeopropithecus and Megaladapis of Madagascar (strictly speaking, Madagascar is not an island but a mini-continent in the context of biogeography)
• Birds
  • Dodo and Rodrigues Solitaire, gigantic extinct pigeon relatives from the Mascarenes, and the extinct flightless Fiji Giant Pigeon
  • Sylviornis neocaledoniae a huge extinct megapode from New Caledonia
  • the extinct Moa of New Zealand
  • Aepyornis, the world's largest bird, formerly living on Madagascar
  • Moa-nalo, extinct giant ducks from Hawai'i
  • the Takahe from New Zealand
  • the extinct Spectacled Cormorant from Bering Island
  • the extinct Broad-billed Parrot from Mauritius
• Reptiles
  • Giant tortoises on the Seychelles, Galápagos Islands and formerly the Mascarenes
  • Komodo dragon, a rare example of a giant insular carnivore (Islands tend to offer limited food and territories, thus island carnivores are usually smaller in size than continental ones)
  • Yellow giant Chuckwalla (Sauromalus varius) of San Esteban
  • Leiolopisma mauritiana and Macroscincus coctei extinct skinks from Mauritius and Cape Verde, respectively, and the rare New Caledonian skink Phoboscincus bocourti
  • the extinct Rodrigues giant day gecko and New Zealand giant gecko, and the extant New Caledonian giant gecko
• Insects
  • Madagascar hissing cockroach
  • St. Helena Earwig
  • Lord Howe Island phasmid
  • giant weta of New Zealand

Many rodents grow larger on islands, whereas lagomorphs, carnivores, proboscideans and artiodactyls usually become smaller. Genera Pentalagus Bunolagus Nesolagus Romerolagus Brachylagus Sylvilagus Oryctolagus Poelagus Rabbits are small mammals in the family Leporidae, found in many parts of the world. ... Genera Anourosorex Blarina Blarinella Chimarrogale Chodsigoa Congosorex Crocidura Cryptotis Diplomosodon Episoriculus Feroculus Megasorex Myoserex Nectogale Neomys Nesiotites Notiosorex Paracrocidura Ruwenzorisorex Scutisorex Solisorex Sorex Soriculus Suncus Surdisorex Sylvisorex Shrews are small, superficially mouse-like mammals of the family Soricidae. ... Subfamilies and Genera Graphiurinae Graphiurus Leithiinae Dryomys Eliomys Hypnomys Myomimus Selevinia Myoxinae Glirulus Muscardinus Glis Dormice are Old World mammals in the family Gliridae, part of the rodent (Rodentia) order. ... The Mediterranean Sea is an intercontinental sea positioned between Europe to the north, Africa to the south and Asia to the east, covering an approximate area of 2. ... Binomial name Papagomys armandvillei (Jentink, 1892) The Flores Giant Rat (Papagomys armandvillei) occurs on the island of Flores in Indonesia. ... Genera Amblyrhiza Clidomys Elasmodontomys Quemsia The giant hutias are an extinct group of large rodents known from fossil and subfossil material in the West Indies. ... The Caribbean or the West Indies is a group of islands in the Caribbean Sea. ... Superfamilies and Families Cheirogaleoidea Cheirogaleidae Lemuroidea Lemuridae Lepilemuridae Indridae Lemurs are part of a class of primates known as prosimians, and make up the infraorder Lemuriformes. ... Binomial name Archaeoindris fontoynonti Standing, 1909 Archaeoindris fontoynonti is an extinct species of lemur and was the largest of the primitive primates. ... Megaladapis is an extinct species of primate that once inhabited Madagascar. ... Biogeography is the science which deals with questions of species patterns of distribution and the process that resulted in such patterns. ... Binomial name Raphus cucullatus (Linnaeus, 1758) The Mauritius Dodo (Raphus cucullatus, called Didus ineptus by Linnaeus), more commonly just Dodo, was a metre-high flightless bird of the island of Mauritius. ... Binomial name Pezophaps solitaria (Gmelin, 1789) The Rodrigues Solitaire (Pezophaps solitaria) was a flightless member of the pigeon family endemic to Rodrigues, Mauritius. ... The Mascarene Islands (or Mascarenhas Archipelago) is the collective title of a group of islands in the Indian Ocean east of Madagascar, which include Mauritius, Réunion, Rodrigues and Cargados Carajos. ... This article is about mound-building birds. ... Genera Anomalopteryx(bush moa) Euryapteryx Megalapteryx(upland moa) Dinornis(giant moa) Emeus Pachyornis Moa were giant flightless birds native to New Zealand. ... Species Aepyornis hildebrandti Aepyornis medius Aepyornis maximus Aepyornis is an extinct genus of flightless bird. ... Genera Chelychelynechen Thambetochen Ptaiochen The Moa-nalos are an extinct group of aberrant ducks that used to live on the Hawaiian Islands in the Pacific. ... State nickname: The Aloha State Other U.S. States Capital Honolulu Largest city Honolulu Governor Linda Lingle Official languages Hawaiian and English Area 28,337 km² (43rd)  - Land 16,649 km²  - Water 11,672 km² (41. ... Binomial name Porphyrio mantelli Owen, 1848 The TakahÄ“, Porphyrio mantelli is a flightless bird native to New Zealand which belongs to the rail family. ... Binomial name Phalacrocorax perspicillatus Pallas, 1811 The Spectacled Cormorant (Phalacrocorax perspicillatus) is an extinct marine bird of the cormorant family of seabirds that inhabited a few islands at the western end of the Aleutian Islands. ... Wikipedia does not have an article with this exact name. ... This page is a candidate for speedy deletion. ... Giant tortoises are characteristic of tropical island life. ... NASA Satellite photo of the Galápagos archipelago. ... Binomial name Varanus komodoensis Ouwens, 1912 The Komodo dragon (Varanus komodoensis) is the largest lizard in the world, growing to an average length of 2-3 meters (10 feet). ... Species Sauromalus ater Sauromalus australis Sauromalus hispidus Sauromalus slevini Sauromalus varius Chuckwallas (less commonly Chuckawallas) are large, bulky lizards found primarily in arid regions of the southwestern United States and northern Mexico; some are found on coastal islands. ... San Esteban (the Spanish-language name of Saint Stephen) may refer to: Philippines San Esteban, Ilocos Sur Mexico San Esteban, Chihuahua San Esteban, Coahuila San Esteban, Tamaulipas This is a disambiguation page — a navigational aid which lists pages that might otherwise share the same title. ... Classification Genus Macroscincus Macroscincus coctei Categories: Skinks ... Genera many—see text Skinks are reptilians belonging to suborder Sauria, and there to the superfamily Scincomorpha, the same as the true lizards. ... Binomial name Phelsuma gigas Rodrigues giant day gecko (Phelsuma gigas (LIÉNARD 1842)) is an extinct diurnal species of geckos. ... The New Caledonian Giant Gecko or Leachs Giant Gecko (Rhacodactylus leachianus), first described by Cuvier in 1829, is the largest of the Rhacodactylus geckos. ... Binomial name Gromphadorhina portentosa , The Madagascar hissing cockroach (Gromphadorhina portentosa) is a large cockroach which is originally from the island of Madagascar off the African coast. ... Binomial name Labidura herculeana (Fabricius, 1798) The St. ... Classification Kingdom: Animalia Phylum: Arthropoda Class: Insecta Order: Orthoptera (related to Grasshoppers, Crickets, and Katydids) The Weta family comprises over one hundred (generally) large insect species endemic to the New Zealand archipelago. ... Families See Classification Section The order Rodentia is the most numerous of all the branches on the mammal family tree. ... Families Leporidae Ochotonidae The Lagomorphs, order Lagomorpha, are an order of mammals of which there are two families, Leporidae (hares and rabbits), and Ochotonidae (pikas). ... A carnivore (KAR-nih-vohr) meaning meat eater (Latin carn = flesh + vorare = to devour) is an animal that eats a diet consisting solely of meat, whether it comes from live animals or dead (scavenging). ... Genera and Species Loxodonta Loxodonta cyclotis Loxodonta africana Elephas Elephas maximus Proboscidea is an order including only one extant family, Elephantidae or the elephants, with three species: the Savannah Elephant and Forest Elephant (which were collectively known as the African Elephant), and the Asian Elephant (formerly known as the Indian... Families Suidae Hippopotamidae Tayassuidae Camelidae Tragulidae Moschidae Cervidae Giraffidae Antilocapridae Bovidae The even-toed ungulates form the mammal order Artiodactyla. ...

See also

• Island dwarfing
• Island rule
• Deep-sea gigantism

Island dwarfing is a biological phenomenon by which the size of animals isolated on an island shrinks dramatically over generations. ... In zoology, deep-sea gigantism, also known as abyssal gigantism, is the tendency for species of crustaceans and other invertebrates to display a larger size than their shallow-water counterparts. ...

External links

• PBS NOVA: Why Do Islands Breed Giants (And Sometimes Dwarfs)?