T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network

Ferret (Mustela putorius furo)

Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: arnivora
Family: Mustelidae
Genus: Mustela
Species: M. putorius
Subspecies: M. p. furo
Scientific name: Mustela putorius furo
Common name: Ferret

The ferret is the largest mustelid in New Zealand, with a body length of 320mm-460mm and a tail of 110-180mm. Males are noticeably larger than females, averaging 1.1-1.3kg (max 1.85kg) with females ranging from 400-1100grams. Ferrets are considerably larger and of 'stockier' build than stoats.
Ferrets have a long and slender body covered with brown, black, white, or mixed fur. The colour is variable, with a typical white or cream undercoat and a variable quantity of longer dark guard hairs, giving some animals a black looking appearance while others appear almost white.
The tail is uniformly dark. A variable dark mask occurs across the eyes and above the nose.
Gestation is 42 days, litters are usually 3 to 7 young, but sometimes more. Females may have two to three litters annually. Young are weaned after 3 to 6 weeks and become independent at 3 months. Sexual maturity may come at 6 months. Average lifespan is 8 years.
Ferrets are obligate carnivores. The natural diet of their wild ancestors consisted of whole small prey, i. e., meat, organs, bones, skin, feathers, and fur.
Ferrets have four types of teeth (the number includes maxillary (upper) and mandibular (lower) teeth). 
Twelve small teeth (only a couple of millimetres) located between the canines in the front of the mouth. These are known as the incisors and are used for grooming. The four canines used for killing prey. 
Twelve premolar teeth that the ferret uses to chew food—located at the sides of the mouth, directly behind the canines. The ferret uses these teeth to cut through flesh, using them in a scissors action to cut the meat into digestible chunks. 
Six molars (two on top and four on the bottom) at the far back of the mouth are used to crush food.

Ecological Impacts (Text from the NZ Dept Of Conservation)
Ferrets are not as widespread as stoats. However, ferrets have a significant effect on many riverbed breeding birds eg. black stilt, dotterel species and pied oystercatcher. Ferrets are known to prey on royal albatross chicks, yellow-eyed penguin and little blue penguin, weka, North Island kiwi, and numerous freshwater wetland birds (eg. ducks).
They are considered as one of the major causes of the decline of the white-flippered penguin, and as a significant and probable main cause (along with cats) of massive range contractions of grand and Otago skinks.
Ground-nesting birds like the rare New Zealand dotterel and extremely rare black stilt, flightless birds like the kiwi, rare lizards and insects are eaten by ferrets. Even the yellow-eyed penguin, blue penguin and royal albatross are not safe from ferrets. Ferrets love eggs and attack and kill chicks and adult birds - even adult kiwi. The threatened giant weta makes a tasty snack, and geckos and skinks are not immune from the dangers ferrets pose.
Species found in the same areas as rabbits are more at risk than others. For example, the black stilt in the rabbit-prone Mackenzie Basin and the New Zealand dotterel on the Coromandel's coastal dunes. However, kiwi is particularly at risk where they share their forest home with ferrets that specialise in rats and mice rather than rabbits. These ferrets are more likely to supplement their rodent diet with kiwi.
Ferrets even threaten New Zealand's farming industry as they can carry bovine tuberculosis (Tb), as possums do. In some possum-free areas, ferrets have tested positive for Tb.


Distribution map of the ferret (Pink area)

 For more details on Mustelids visit Northland Regional Council website: http://www.nrc.govt.nz/Environment/Weed-and-pest-control/Pest-animals/Mustelids/#stoats

Thanks to Wikipedia for text and information http://creativecommons.org/licenses/by-sa/3.0/