Antechinus The Sex Crazy Marsupial

Antechinus Description Appearance of Antechinus

Photo: Antechinus

The antechinus is a mouse-like Australian marsupial animal with a crazy sex life. The male antechinus mates itself to death. The antechinus is roughly the shape, size and appearance of a house mouse, measuring 9–120mm long and weighing 17-71gm. Antechinuses have short, stiff fur and come in upper body colours of grey, brown, black and golden. Their underbellies are beige or white. Antechinuses have long snouts, four pairs of sharp teeth, bulging dark brown eyes, and pink to light brown nostrils. A distinguishing feature is their notched ears which make them appear like double ears. Males are larger than females.

There are 15 species of antechinuses in Australia. The most common are the Yellow-footed, Agile, Dusky and Brown antechinuses. The agile antechinus is the smallest and the dusky antechinus is the largest.

Antechinus Habitat Where Do Antechinuses Live?

Antechinuses live in temperate and tropical forests, woodlands and swamps on the east coast of Australia. There is also a small population in southwest Western Australia. Most antechinuses are ground-dwelling. But are also arboreal and live in trees. They are solitary, territorial animals that will actively defend their territories. They do this by standing on their hind legs and ferociously clawing at each other's shoulders and backs until one is defeated and withdraws. A male has a more extensive territorial range than a female who forages closer to her nest. Most antechinus species nest communally in tree hollows. Up to 20 may share a nest.

See the detailed description of various antechinus species below for details of their unique habitats.

Antechinus Diet What Do Antechinus Eat?

Antechinuses eat insects such as spiders, weevils, beetles, etc. Their sharp teeth, speed, and agility enable them to overwhelm creatures much larger than themselves. They have an unusual habit when eating small bony animals of neatly turning their skins inside out while eating them. Antechinuses also eat insect larvae, worms, small lizards and frogs. Some eat fruit and flowers and sip on nectar.

Antechinus Reproduction Antechinus Mating to Death

Antechinus males are known for being sex crazy. They have a suicidal reproduction strategy called semelparity or "big-bang" reproduction. They breed only once in their lifetimes and then die. This behaviour is very rare in mammals. Other animals that practice this behaviour are salmons and mayflies. Antechinuses only gather together for mating, which is usually between August and September.

Male Antechinus

A male antechinus will mate for up to 14 hours at a time and then die of exhaustion shortly afterwards. During this two to three weeks of speed-mating, the male antechinus becomes so focused on sex that he doesn't eat, drink, or sleep. Instead, during these two to three weeks of sexual frenzy, testosterone-fuelled males have violent, frenetic sexual intercourse with as many females as possible. He does little else. Their sex drive is so all-consuming that the male's body is stripped of proteins, and his immune system shuts down to release all available resources for procreation. So it isn't long before the poor male is worse for wear. His fur begins to fall off, and his internal organs slowly disintegrate. Without an effective immune system, he shows signs of disease. But the poor creature is still after more sex until it eventually kills him.

There seems to be a logical reason for this suicidal sex romp. By impregnating as many females as possible and then the male dying, the antechinus population is cut by half. This leaves more food for the pregnant females to feed and raise their offspring. Nature, no doubt, works in mysterious ways. The lifespan of a male antechinus is typically only one year.

Female

An impregnated female stores sperm from her multiple partners in a special sperm-storage area in her ovaries and does not ovulate until the end of her mating period. She then releases her eggs and lets them be fertilised by the sperm she has held in storage. As a result, her eggs are fertilised by sperm from multiple males, and her litter will have multiple fathers.

The gestation period is approximately one month, after which tiny babies born blind, hairless, with stumpy forelimb and hardly any trace of hind legs emerge from the mother's birth canal and crawl up to her very rudimentary pouch, which is just a slight depression with nipples. It is a first-come-first-serve free-for-all for the babies because while the female may have a litter of up to 14 young, she has a limited number of nipples. Only those babies who succeed in latching onto one of her available nipples survive. The others quickly die and fall off.

The babies will remain firmly latched on to their mother's nipple, hanging on for dear life in her shallow pouch, as she scampers about hunting for prey. When they are about eight weeks old, they would be too large for her pouch and may be left behind in her nest or may clamber up onto her back for a piggy-back ride as she goes hunting. Then, a few weeks later, they will start following her about and learning survival and hunting skills from her. The young are fully independent when they are about three months old, at which time most mothers die. Some females, however, have a lifespan of up to three years.

Babies

Antechinus babies are the tiniest of Australian native animal babies. When born, they are just 4-5 mm in length (That's smaller than a grain of rice!) and weigh an average of 0.016gm.

Antechinus Species 4 Types of Antechinus

Yellow-footed Antechinus

The yellow-footed antechinus (Antechinus flavipes) has a variable fur colour depending on its habitat. It usually has a grey upper body with a golden-brown belly, white-eye rings and a black-tipped tail. It has broad yellowish feet — hence its name, yellow-footed antechinus. Its body is about 10-16 cm long with a tail of an additional 10cm. The male weighs around 30gm and the female 28gm. It has a jerky movement.

The yellow-footed antechinus lives mainly along the north-eastern and, to a lesser extent, the south-eastern parts of Australia. A small pocket is also found in the southernmost parts of Western Australia. A tiny population live in South Australia, where they are considered endangered. The yellow-footed antechinus is a terrestrial animal preferring to scamper about the leaf litter forests, heath, woodlands, and coastal plain. It is the most widespread antechinus species. It is active mainly during the day.

Agile Antechinus

The agile antechinus (Antechinus agilis) is the smallest of all antechinus. It has a body length of 8–11cm with a bristly tail of an additional 11cm. It weighs 16-44gm. This antechinus has greyish brown upper body fur and pale under-body fur. It has lightly coloured fur forming narrow rings around its eyes. Until 1980 it was classified as a member of the brown antechinus species, but DNA tests determined that it was a species of its own. It is a nocturnal insectivore. The female gives birth to a litter of between 6–8 babies. The female gives birth to a litter of between 6–8 babies.

The agile antechinus is a ground-dwelling marsupial that lives amongst dense leaf litter and fallen logs in the forests of south-eastern Australia. It nests in log hollows and crevices where up to 20 individuals may share a single nest.

Brown Antechinus

The brown antechinus (Antechinus stuartii) is a nocturnal mostly arboreal antechinus. That is, it is active at night and lives mostly in trees. As a result, it is an excellent climber. The fur on its upper body is brown, and its under-belly is usually white or beige. It has a body length of 7–14cm, and its tail is about 11cm and mostly hairless. It weighs 16–44 grams. Unlike other antechinuses, it doesn't have pale-coloured eye rings. This antechinus is known to go into a torpor where it can drop its body temperature to 11–25 degrees and reduce its metabolic rate by up to 60% to conserve energy in times of starvation.

The brown antechinus lives in wooded habitats east of the Great Dividing Range in Australia. Females share communal nests.

Dusky Antechinus

The dusky antechinus (Antechinus swainsonii) is the largest species of antechinus. Its fur is dark grey to black. Its body is 9–18cm long with a tail that is 8-12cm long. The male weighs about 65gm, and the female 41gm. It is a nocturnal insectivore but may also be active during the day. The female gives birth to a litter of between 6–8 babies.

This ground-dwelling marsupial lives in alpine heath or forest with dense fern or shrub under-storey along the eastern coast of Australia and on the island of Tasmania. During the day, it rests in a nest in a hollow log or hidden in ground litter or vegetation.

Antechinus Predators and Threats What Kills Antechinuses?

Snakes, lizards, foxes, dingoes, large birds, feral cats, and domestic cats and dogs kill antechinuses.

Antechinus Conservation Status Is the Antechinus Endangered?

The antechinus is not endangered. It is protected in all states of Australia.

How the Antechinus Got its Name What Does Antechinus Mean?

The scientific name Antechinus (pronounced ant·echi·nus) was first used in 1841. It is derived from the Greek words 'anti' + 'ekhinos'. Most references tell us that 'ant, anti or ante' in Greek and Latin mean 'against' or 'opposed to' (such as antacid, antifreeze, anterior). Dictionaries also tell us that ekhinos means sea urchin or hedgehog. The antechinus definitely has a pointy nose and bristly fur like a hedgehog, but it is not a placental mammal like the hedgehog. So 'Antechinus' means — not a hedgehog.

Antechinus or Rat Differences Antechinus vs Mouse

People frequently mistake the antechinus for a rat or house mouse, but they are very different.

The antechinus is a marsupial mammal that carries its babies in a pouch on its belly. It also has many small sharp teeth, five-clawed toes on its front feet and four clawed toes on its rear feet. It has rounded, crinkly ears that look like double-ears. It also has a tail with fur.

The house mouse is a placental mammal. It has chisel-shaped front teeth, four-clawed toes on each front foot plus a clawless insignificant thumb. It has a five-clawed toes on its rear feet. It has smooth rounded ears and a scaly tail. The house mouse is not native to Australia. It was introduced to Australia by European settlers in 1788.