The weasel is the smallest member of the mustelids (ferrets, stoats, otters) and the world's smallest carnivore. It was introduced into New Zealand in 1885, to help reduce rabbit numbers, along with ferrets and stoats, but, although released in greater numbers, did not thrive.
The government changed its release policy in 1903 but it was too late. It was not until 1936 that legal protection was removed.
Weasels are found worldwide except for Antarctica and Australia. They inhabit a wide range of environments, from pastoral land and scrub to exotic forest and bush margins. They are great predators of mice but also prey on native birds, eggs, lizards, insects and frogs. They are efficient hunters, and will kill even when their belly is full.
Their slender shape and short legs allow them, uniquely, to enter the burrows of prey where they corner their victim, wrap themselves around the prey to immobilise it and then bite the back of the neck to kill. They then take over the burrow, lining it with fur and leaves to make it a den.
They hunt both day and night, mainly on the ground, but can climb. Hunts can cover 2.5km at speeds of up to 25km/h. Prey can include animals much larger than themselves, and surplus can be carried back to the den and cached for later use. Their body shape, size and metabolism mean they have a very high energy demand and need to eat one-third of their body weight in food each day.
