What do they look like?
• The possum is a mammal about the same size as a cat and males are larger and heavier than females.
• Possums have a long bushy tail, which is around a third of the total length.
• Possums have big ears, large, dark eyes, and long claws.
• Possum fur is soft and thick but the colour varies widely from brownish grey to almost black. The belly fur can range from white to ginger.
Have you ever wondered….?
Why some possums have very dark fur while others have very light fur?
Most of the possums introduced to New Zealand were known as Tasmanian blacks because of their darker fur. These possums were prized over the mainland grey possums for their superior fur which was sleeker. However, the greys are now more common around New Zealand except in the wetter areas of the country such as Fiordland.
Did you know?
Possums are not native to New Zealand.
The first possums were brought here in 1837 from Australia.
Possums are native to Australia where they are protected.
Possums are not a problem in Australia, in fact, they are endangered in some areas.
Possums were brought to New Zealand to start a fur industry.
At the height of the fur trade, trappers killed 20 million possums in a year which helped to control possum numbers.
It’s a fact
When possums were first released into some areas of New Zealand, such as the Wairarapa, school children were given the day off school to mark the historic event!
Where do they live?
• Possums are found throughout the New Zealand mainland and on a number of offshore islands.
• Possums are very hardy and adaptable, and can survive in most environments as long as there is a good food supply.
• They will live anywhere there are trees – including your garden, particularly if you have nice things for them to eat such as fruiting trees and roses, and nice warm places for them to sleep – garden sheds, old hollow stumps are considered very luxurious!
Did you know?
Possums belong to a special group of mammals called marsupials. This means that the baby possum is born when it is still very tiny and continues growing in a special pouch on its mother’s stomach instead of inside its mother’s tummy.
Marsupials are found only in Australia. There are 200 different kinds of marsupials in Australia.
Other marsupials are the wallaby (which was also introduced to New Zealand), kangaroo and koala. That makes the possum the cousin of the kangaroo.
What do they eat?
• Possums are active at night and generally emerge from their dens about 30 minutes after sunset. They return just before dawn in the summer, but often earlier in the winter.
• Possums are omnivores, which means that they eat both meat and veges, although plants tend to be their main food source.
• Possums have favourite foods and will selectively feed on these until they have been destroyed. This is often why you will see single dead trees in otherwise healthy looking forests.
• On farmland possums are partial to clover. They will also eat crops grown for stock food such as barley and rye, particularly if the paddock is between two areas of forest.
• Possums regularly eat invertebrates such as weta and snails, and are known to eat the chicks and eggs of native birds (e.g. kokako, kereru, fantail, and muttonbird).
• They may also feed on the carcasses of deer, rodents and other possums.
Possums are eating up New Zealand!
In one night 20 possums can eat six kilograms of vegetation – that’s enough leaves, fruit and vegetation to fill three plastic shopping bags. That doesn’t sound like so much, does it? But wait there’s more!
In one week 20 possums can eat 42 kg of vegetation – 21 shopping bags full.
In one month 20 possums can eat 180 kg of vegetation – 60 shopping bags full.
In one year (365 days) 20 possums can eat over two tonnes of vegetation – 1000 shopping bags full. Do you think that would fill your classroom?!?
In one night 35 million possums chomp their way through nearly 12,000 tonnes of vegetation. That is about the same weight as 110 million hamburgers! If the people in New Zealand (there are nearly 4 million of us now) were to eat the same amount as all the possums in New Zealand we would all have to eat 28 burgers for dinner each!!!!!
In one year 35 million possums eat over four million tonnes of vegetation. That is too many burgers to even think about!
Who can it be now?
• Possum tracks or regular trails going to and from feeding and sleeping areas can be visible as narrow strips of ground worn down to bare dirt by many pairs of possum feet.
• Trees favoured by possums may have the bark worn smooth with claw marks around the base or on the trunk, especially evident on totara. A possum track will often end at the base of the tree.
• Leaves browsed by possums have torn rather than cut edges, often with the midrib and lower part of the leaf partly remaining.
• In your garden possums will eat newly formed buds off fruit trees and new growth on roses in spring. Lemons and feijoas will hang on the tree with only their peel or skin eaten; vegetables will usually be completely eaten.
• Palatable forest trees and coastal species such as pohutukawa, tree fuchsia, northern rata or kamahi can be completely defoliated, particularly those with a warm sheltered aspect.
Did you know?
Many trees in Australia have possum defenses such as spines, prickles or poisonous leaves which limit the amount possums can eat from any one tree.
In New Zealand possums have no natural enemies and most native trees do not have possum defenses.
Rimu, kawakawa and ferns are not browsed by possums because they contain terpenes (similar to turpentine and not nice to eat). Matai, miro, kahikatea, beech, karaka, coprosma, rewarewa, lancewood, pukatea, and nettle are just like brussel sprouts on your dinner plate. Possums don’t like to eat them.
The possum’s favourite trees are pohutukawa, rata, totara, kowhai and kohekohe. Possums like to eat the juicy new growth on trees. They
will go back to the same tree night after night. This means that each time the tree puts out new growth it is eaten until eventually it is eaten to death. After two years of browsing by possums the old leaves on the tree fall off and with no new growth to replace them the tree will die.
What effects do they have on the New Zealnd environment?
• Possums like to eat the flowers of native trees. This means that they are eating the food of our nectar feeding native birds such as the tui, bellbirds and kokako.
• By eating native trees the possums are also eating the homes of native birds.
• Possums disturb nesting birds and sometimes eat the eggs, chicks, and even adult native birds. Possums have been caught on camera eating kokako eggs and chicks.
• Possums have even been known to push kiwi out of their burrows so they can have a dry place to sleep!
• By eating native invertebrates such as weta and snails possum are not only competing with native species that rely on insects but also threatening the species population. A single possum can eat more than 60 native Powelliphanta snails in one night.
• Possums can also be a problem down on the farm. They just love clover, crops (including orchards and berry fruit) and shelterbelts. It has been estimated that possums consume several million dollars of pasture annually.
• Possums cause problems in city gardens too. They eat trees in people’s gardens, especially apple, plum, citrus fruit, and roses. Possums are noisy and can keep people awake, and they have been known to go inside houses!
Curiosity killed the cow?
Possums can spread a disease, called ‘bovine tuberculosis’ or TB, to cows and deer. If the farmer’s animals get tuberculosis they will get sick and may die. Scientists think that the curiosity of a cow may be its downfall. Possums with advanced stages of TB are often lethargic and in paddocks are licked or sniffed by cattle, thereby passing on the disease.