The Hamilton's frog (now synonimised with the Maud Isand frog) is one of the three last surviving endemic Aotearoa New Zealand frogs left of the ancient family of Leiopelma. It's also the biggest of the surviving Aotearoa frogs.
Growing up to 50mm, these tiny dark brown frogs are nocturnal and rarely seen in the day being sheltered under large rocks, crevices, or within boulder piles. They are most active during warm humid nights but not as much on full moons. As ambush predators, they like sitting and waiting till insects come their way to catch them with their mouths. With no vocal sacs, the Hamilton's frog doesn't croak but at most will very rarely make a squeak sound when threatened. Despite not having ear drums and a tail, the frog still has the set of muscles used for tail-wagging. Without a voice or a tail to attract mates, these frogs send out chemical signals to each other. With a average life span of 33 years, they travel rarely and their lifetime range around 30 square metres.
Having adapted to life without mammals, when faced with threats, they 'freeze' and rely on their appearance to avoid predators. This puts them at a huge risk to mammalian predators. In addition to diseases, such as Zoospores and Chytrid, this lead to their once ambundant numbers declining throughout Aotearoa prior to being rediscovered in the 1940s surviving only on the mammal-free Maud Island. Despite having a population of 40,000 (2013) on the island, there are risks in relying on a single population in case of a natural disaster or a disease that could easily wipe out the population.
With successful translocations to Motuara Island in 1997 and less successful translocation to Long Island due to poor habitat and predation by kiwis, 60 Hamilton's frogs were first transferred to Zealandia in 2006 and another 101 in 2012. This is a huge step for Hamilton's frogs as this was the first reintroduction of a native frog back to mainland and the first to co-exsist with mice. With the release of 101 frogs outside the enclosures in 2012, 86% were recaptured at least once after release showing that kiwi and mice have no significant negative impact on frogs. Breeding has occured successfully between the three enclosures that the other Hamilton's frogs were kept in at Zealandia and outside the enclosures.