New Zealand is an archipelago of very ancient origin. These islands were separated from Gondwana supercontinent at the end of Mesozoic, therefore many representatives of terrestrial fauna not able to swim or to fly simply could not reach this isolated world. Earlier at the islands ground-dwelling mammals were absent: only pinnipeds and bats were native inhabitants of islands. And the most part of ecological niches at the islands had been occupied by huge flightless moa birds of various species. After the introducing of mammals to the islands and after the extinction of people the new page of evolution of fauna of these islands had been written. The fauna of island has lost the unique features caused by isolation, and became more similar to fauna of continents. Among the animals introduced to the islands there were some species of carnivores of mustelid family. Presence and evolution of these predators have strongly affected the ways of evolution of fauna of islands – in Neocene in fauna of New Zealand there is very little number of ground-dwelling and flightless birds. Mustelids have formed some species occupying various ecological niches.
One species of Neocene New Zealand predators, feeding on small ground-dwelling animals is New Zealand unbadger, which is very large descendant of the ferret (Mustela putoris) introduced to the islands. This is a massive mammal, little bit similar to badger, about one meter long. Coloring of animal’s head is striped, that gives to it the remote similarity to badgers: eyes are surrounded with dark strip, which prolongs forward as a dark strip along the nose bridge. Sides of head and forehead of animal are colored light grey, almost white, and nape is rusty-red. The lower jaw and chin of animal are dark. The wool on lateral parts of head is lengthened and forms “sidewhiskers” hiding short ears of animal. Body of New Zealand unbadger is thick and heavy, with short legs and short fluffy tail. Wool on the top part of animal’s body is brown with small spots on sides, stomach is colored lighter. But this animal differs from badger externally: its muzzle is short, with massive jaws, strong chewing muscles and wide crushing teeth. The tail of unbadger is covered with very long white hair forming a rich tuft. Warning the enemy about intention to protect itself, this animal jerks it up and shakes. If the enemy continues attempts to attack this animal, unbadger protects itself with the help of smelly liquid secreting by anal glands. Beast sprinkles it in air, creating a smelly cloud, which smell is intolerable for sense of smell of mammalian predators. If this way of protection does not help, animal attacks the enemy and puts to it strong bites and wounds by forepaws. In its habit of life New Zealand unbadger is remotely similar to its prototype from Eurasia and North America. It is ground-dwelling plantigrade animal, which is not able to climb trees, but digs the ground very well and builds deep holes. Claws of this mammal are very long; on forepaws they are thicker, rather than on rear legs. New Zealand unbadger is omnivorous and unfastidious in choice of food. It eats with equal pleasure vegetable food (up to 40% of its diet) and various animals – from small reptiles and nestlings of ground birds up to carrion. With the help of strong paws New Zealand unbadger digs out of the ground roots and insect larvae. In ecosystems of New Zealand where limited island resources can’t support many species of the specialized predators, it fills a favourable ecological niche of “universal” omnivore. New Zealand unbadger frequently feeds on carrion or the rests of prey of other predators. This mammal leads a solitary way of life. Every unbadger occupies territory of total space of about one square kilometer, where some holes are made, used by animal alternately. This animal digs holes by itself among roots of trees, in bushes or under stones. Depth of hole may reach 5-6 meters, and in it there may be some emergency exits. At the bottom of the hole there is a living chamber with litter of plant matter. When in hole parasites become too numerous, animal leaves it, moving to the next one. Borders of territory are necessarily marked with odorous secretions. Separately standing trees or large stones usually serve as boundary marks: on them some different animals leave labels simultaneously. Seasonal prevalence in breeding of New Zealand unbadger is expressed only at the southern borders of an area, where female brings posterity only once a year. In tropical conditions on Northern Island of New Zealand female gives rise to posterity twice per one year. In litter at this species there are 2-3 well advanced cubs. They open eyes for the second day of life, and at week age begin leaving hole for games. At young animals front part of head is light, and dark marks appear to the time of sexual maturity at the beginning of the second year of life. Young animals remain with female up to 3-4-monthly age. Life expectancy of New Zealand unbadger is about 25-30 years.