The Antechinus is a small mouse-like Australian marsupial. It is a ferocious hunter, preying on insects and small animals such as frog and lizards. Sometimes referred to a marsupial mouse; it has little in common with a mouse.
The antechinus has recently gained a reputation for being the most oversexed animal in world because of its suicidal sexual behaviour.
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.
An Antechinus are roughly similar in appearance to a mouse but has an elongated snout with four pairs of small sharp teeth, bulging eyes and large thin crinkly ears with a notch on the edge. It also hops about more than a mouse. Most importantly it is a marsupial.
Because they are very similar in appearance, people frequently mistake the antechinus with the Australian house mouse.
The antechinus is a native Australian marsupial mammal (it carries its babies in a pouch on its belly), has many small sharp teeth, five clawed toes on each front foot 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
The Australian house mouse is a placental mammal introduced to Australia in 1788 by European settlers. 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.
Antechinuses range in size from 9–120mm. Their tail is half their body length. They are roughly the shape and size of a house mouse. Males are larger than females. The agile antechinus is the smallest and the dusky antechinus is the largest.
Antechinuses have short stiff fur and come in upper body colours that include grey, brown, black and golden. They have lighter coloured underbellies of beige or white. Antechinuses have dark brown eyes and pink to light brown nostrils.
Most antechinuses are ground dwelling animals. A few are arboreal and remain in trees. They live in temperate and tropical forests, woodlands and swamps. 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 withdraws defeated. A male has a larger 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.
Antechinuses are fierce little insectivores - insect eaters; who hunt insects such as spiders, weevils, beetles and other insects. Their sharp teeth, speed and agility enable them to overwhelm many creatures larger than themselves.
They also eat insect larvae, worms and small lizards and frogs. Some also eat fruit and flowers and sip on nectar. It has an unusual habit when eating small bony animals of neatly turns their skins inside out while eating them.
Antechinuses only gather together during mating season which is usually between August and September. Most antechinus species have a suicidal reproduction strategy known as semelparity or "big-bang" reproduction where the animals breed only once in their lifetimes and then die. This behaviour very rare in mammals. Other animals that practice this sort of behaviour are salmons and mayflies.
Antechinus males have a reputation for being sex crazy. During the mating season males 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, he becomes so focused on sex that he forgets to eat, drink and sleep. Instead, during this 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 striped of proteins and the immune system shut 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, internal organs slowly disintegrate, and without an effective immune system he shown 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, fulfilling his procreation role and then dying, the antechinus is population effective 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 a year.
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 minuscule little 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 survives. 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. 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 of the mothers die. Some females however have a lifespan of up to three years.
Antechinus babies are the tiniest of Australian native animal babies. When born they are 4 to 5 mm in length (That's smaller than a grain of rice!) and weigh an average of 0.016 gm.
The yellow-footed antechinus (Antechinus flavipes) has a somewhat 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 mostly 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 very small 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 mostly active during the day.
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 colour fur forming narrow rings around its eyes. Until 1980 it was classified as being 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.
The dusky antechinus (Antechinus swainsonii) are the largest species of antechinus. Its fur is dark grey to black in colour. Its body is 9–18cm long with a tail that is 8-12cm long. The male weighs about 65 gm 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 its rests in a nest in a hollow log or hidden in ground litter or vegetation.
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 in colour. 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 a wooded habitats east of the Great Dividing Range in Australia. Females share communal nests.
The antechinus are protected in all states of Australia. They are not believed to be endangered.