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Hamilton's frog
Conservation status
Endangered [1]
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Amphibia Order: Anura Family: Leiopelmatidae Genus: Leiopelma Species: L. hamiltoni
Binomial name
Leiopelma hamiltoni McCulloch, 1919
Range of Leiopelma hamiltoni.

Hamilton's frog (Leiopelma hamiltoni) is a New Zealand primitive frog, one of only four belonging to the ancient family Leiopelmatidae. It is named after Harold Hamilton, who first collected the species.^[2]

It is found only on two small sites on mammal-free Stephens Island in the Marlborough Sounds area at the north of the South Island of New Zealand. It is probably the rarest frog in the world.

It does not have webbed feet, but has atavistic tail-wagging muscles although it does not have a tail. The eyes are round, not slit, and there is no external eardrum. It does not go through a tadpole stage, but instead develops totally within a gelatinous capsule derived from an egg, and therefore does not need standing or running water for reproduction. The male Hamilton's frog may carry his young offspring around on his back. Hamilton's frogs are very dependent on a damp environment however, and quickly dry out and die if placed in a dry place.

Apart from their rarity Hamilton's frogs are hard to locate as they are well camouflaged, are nocturnal, and do not croak. They are generally dark brown blotched with green and light brown.^[3]

On Stephen's Island until 1992 the endangered Hamilton's frog was confined to one small, severely modified habitat - 600 m² of rock rubble. This habitat had become susceptible to climatic extremes through loss of vegetation cover, and to enhance the population, estimated to be around 300 frogs, a new habitat was created between July and October 1991 in a nearby forest remnant 40 metres from the original site, by excavation of pits and backfilling these with rocks. A predator-proof fence was built around the new habitat to exclude tuatara (Sphenodon punctatus), and the area was "seeded" with invertebrate prey. Twelve adult frogs were transferred to the site in May 1992. The species remains endangered.^[1]

1. ^ ^{a b} Tocher et al (2004). Leiopelma hamiltoni. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 11 May 2006. Database entry includes a range map, a brief justification of why this species is endangered, and the criteria used.
2. ^ Leiopelma hamiltoni: Hamilton's Frog. AmphibiaWeb. Retrieved on 13 June 2006.
3. ^ Chris Mattison (1992). Frogs & Toads of the World. London, UK: Blandford. 

• Transfer
• Predation by tuatara