Echidna (Spiny Anteater)A Living Relic from Early Mammals
The echidna sometimes referred to as a spiny anteater, is a monotreme — an egg laying mammal. Even though it's a mammal, like you and me, it lay eggs like a bird or reptile but feed its baby milk like a normal mammal. It is one of the oldest surviving example of early mammals and its anatomical makeup shows the evolutionary transition of prehistoric reptile and bird-like egg layers to milk-feeding mammals.
Echidnas are usually black or dark brown in colour. They have roundish stocky bodies covered with sharp beige and black spines somewhat similar in appearance to other spiny mammals such as hedgehogs.
Types of Echidnas
There are two species of echidna: the short-beaked echidna, found in Australia and New Guinea and the long-beaked echidna found only in the highlands of New Guinea. The short-beaked echidna is the smaller of the species. There are five subspecies of short-beaked echidna in Australia.
Size and Weight
An echidna measures between 30 to 45 cm in length and weighs approximately 2 to 7 kilos. Male and female echidnas are identical in appearance. A fully grown male echidna, however, is about 25% larger than the full grown female.
Body, Fur and Spines
Echidnas colour varies depending on their geographic location. In the hotter northern regions they are light brown, but become darker in colour, with thicker fur, further south. In Tasmania the coldest area which they live, they are black. Two types of fur covers their bodies. A coat of short coarse fur insulates the animals from extreme weather. While longer specialised hairs commonly referred to as "spikes" protrude from the undercoat and cover the animal except for its face, legs and underside. These spikes are pointed but hollow quill-like structures made up of keratin, the same material that makes up our fingernails. The echidna's tail is short, stubby, very spiny on the top and hairless underneath.
Head, Eyes, Ears & Beak
The Echidna's Sensitive
The echidna is one of the few land animals to have electro-receptors in its snout, like sharks, and the platypus. These receptors enable the echidna to locate pry, such as inserts and worms, by detecting the electrical signals they emit. The long-beaked echidna which lives in damper climates has as many as 40,000 electroreceptors on its beak. The short-beaked echidna on the other hand has only about 400 such receptors. Scientist believe the reason that the short-beaked echidna has less receptors is because it lives in a drier climate where due to the lack of moisture these receptors would be less affective (water moisture is a good conductor of electricity).
The echidna has a tiny face with small eyes. Its eyesight is poor but it makes up for this with excellent sense of hearing and smell. The echidna has no external ears but has funnel-like slits on either side of its head which are well hidden beneath its fur and spines (see photo on left). Its slender elongated rubbery snout, called a beak, functions as both a mouth and a nose. At the tip of this beak, on the top, are its nostrils and on the bottom is a very small mouth with toothless jaws, which can only open about 5 mm, from which the echidna sticks out a very long sticky and flexible tongue with which it catches its prey. The tongue can flick in and out at up a 100 times a minute.
The echidna has a distinct gait with short, stout limbs positioned on the side of its body like the platypus and reptiles. Its limbs are ideal for rapid digging. Its front feet have five flat claws forming an effective spade for digging, to burrow, dig up forest litter and to tear open termite mounds and rotting logs. Its hind feet point backwards, and help it push soil away while the animal is burrowing. The second claw on each hind foot is extra-long and also helps in grooming, where it is used to comb and scratch out dirt and bugs from its fur and spines.
Other Unusual Characteristic of Echidnas They are Unusual Animals Indeed
Besides being an egg laying mammal which indeed is unusual, the echidna also has a number of other characteristics which makes it quite unique.
Lower Body Temperature than Mammals
Echidnas have a body temperature of between 31-32°C which is between 5 to 8°C lower than other mammals. For example a rabbit's body temperature is 38–40°C.
The echidna has only one opening at the end of its body called a cloaca. This all-in-one opening is the exit of a common chamber into which the intestinal, genital, and urinary tracts discharge. This is a common characteristic amongst birds and reptiles but very rarely found in mammals. In other mammals these are separated into two openings, namely the rectum/anus and reproductive tracts such as the vagina and penis.
The echidna is one of a very few Australian animals that hibernates. (The others are four species of possum and a few bats). It is also the largest of these hibernating Australian animals. Hibernation is an extended period of deep sleep or inactivity that allows an animal to survive extreme environmental conditions such as the coldness of winter. In this state of near suspended animation the animal’s heart rate, breathing and body temperature drops significantly thereby conserving energy. During hibernation an echidna’s body temperature falls to very close to that of temperature of the soil around it. This can be as low as 4.7°C, with a reduced heart rate of just 4 beats per minute.
Hibernation usually starts in late summer and ends in June-July. During the hibernation echidnas regularly rewarm themselves and may move to another location. They seem to do this to find the coldest rest spot when its hotter and the warmest rest spot when it gets cooler thereby maintaining an optimal hibernation body temperature. In this state the echidna's metabolic rate is around 30% of that of an equivalent sized placental mammals, making it the lowest energy-consuming mammal in the world. In cold areas echidnas hibernate for 6-28 weeks. Males go into hibernation earlier than females with young and yearlings that don't breed stay longer in hibernation.
The echidna uses hibernation as a hardy tactic to deal with the extreme heat of bushfires too.
Smaller Neocortex than Other Mammals
The echidna's neocortex makes up about half its brain. In a human it is about 76%. The neocortex is the most recent part of the brain to evolve. This too highlights the fact that these are the last of a prehistoric group of animals pre-dating modern mammals.
Spurs on Its Hind Legs
The echidnas are born with a spur on each of its hind legs. These soon disappear in the female. These spurs may once have produced venom and have served a defensive purpose (like the poisonous spurs of the platypus). The spurs of the echidna today seem to serve only a communication function. Recent research suggests that the echidna secretes a waxy substance from these spurs which it uses to mark its territory to indicate its readiness to mate to females, or as a signal to other males to keep away.
The average lifespan of an echidna in the wild is estimated to be around 16 years. Some are known to have lived to up-to 45 years of age. Their longevity is attributed to their rather "laid back" lifestyle and low metabolic rate.
How Did the Echidna Get its Name? The Echidna is Named After a Greek Goddess
The name Echidna is derived from the Greek name Ekhidna. Because the echidna appeared to be half reptile and half mammal , in 1802 the British anatomist Everard Home named this unusual animal after the Greek goddess Ekhidna (meaning "she viper") who was half-snake and half-woman.
The name Echidna is pronounced e-kid-na.
Scientific Name: Tachyglossus aculeatus (Means quick tongue + equipped with spines).
Echidnas are Australia's most widely dispersed native mammal. They are found throughout Australia in almost all habitats, from snow covered mountains to deserts and even urban areas. They are shy well-camouflaged animals that you would seldom encounter. They are usually found among rocks, in hollow logs and in holes among tree roots or rummaging through leaf litter or sometimes in wombat or rabbit burrows.
For most of the year echidnas are solitary territorial animals roaming over a large territory that often overlaps with the territories of other echidnas. While there is an adequate food supply echidnas will generally remain in a fixed location.
Echidnas tend to avoid temperature extremes. In temperate climates, echidnas are most often seen during early morning and in the late afternoon. In arid hot environments, echidnas forage during the night and shelter in rock crevices, burrows or caves during the hotter parts of the day. This is because echidnas do not have sweat glands nor do they pant to loose body heat.
Like most Australian animals, echidnas feed during the mornings and evening when the temperatures are the coolest and rest during the hottest part of the day. In extremely hot climates they only forage for food at night.
The nostrils and electroreceptors at the tip of its beak help the echidna detect its food which is usually hidden away within a termite mound, anthill, a rotting log or under leaf litter. Once it have detected its prey the echidna uses its powerful claws to rip open a termite mound or the bark or truck of a tree. It then flicks its long sticky 15-centimeter tongue in and out to lap up its prey. The echidna has no teeth. So it uses hard pads at the base of its tongue to push up against the roof of its mouth and grinds its meal into a paste before swallowing. Echidnas get most of the water they require from their diet. This is sometimes supplemented by drinking water or by licking morning dew from plants and grasses.
Echidna Reproduction A Baby Echidna is Called "Puggle"
Echidnas are solitary animals that prefer to live alone. The only time they socialize is, between June and early September, when female echidnas are in season and receptive to advances from males. The typical echidna mating ritual is one of pursuit where up to 11 males echidnas form a line, sometimes referred to as a “love train”, and follow a female around for extended periods of time and try to mate with her. During this time a male may switch from one line to another if he feels so inclined. Usually it is the male who endured the longest and stuck closest to her is the successful suitor.
Echidnas are promiscuous, mating with as many partners as possible. As a consequence during the mating season a male echidna’s testes, located inside its body, can grow to up to 1% of its body mass. These larger testes allow the male to ejaculate more frequently thereby enabling it to take part in a greater number of mating encounters.
Echidnas mate by lying on their sides with their spineless undersides facing each other, so their spiky spines don't get in the way. The male penis located inside its cloaca is extended out and inserted into the female cloaca for impregnation.
Egg Laying, Incubation & Hatching
After fertilization the female begins to develop a temporary pouch which is essential a depression in her abdomen covered by two overlapping flaps of skin. Approximately 16 days after fertilization she lays a single leathery egg, roughly the size of a small grape (13–16 mm), into her pouch. Nobody knows for certain how she does this. Some suggest that she collects the egg as it comes out of her cloaca and deposits it into her pouch. Another, more likely scenario, is that she curls up into a shape like the letter “C” and deposits the egg from her cloaca directly into her pouch. She then incubates the egg in her pouch for 10 days.
On about the tenth day the young echidna, referred to fondly as a puggle, uses its eye-tooth, another example of its reptilian ancestry, to tear through its leathery shell and exists into the pouch. At this stage it has well developed forelimbs and is about the size of a small jelly bean. The puggle uses its forelimbs to hold onto fur in its mother's pouch.
Milk but No Nipples
The mother echidna has no nipples or teats like other mammals. Instead it oozes milk through its skin from specialised milk patches. The puggle nuzzles up against these patches which encourages them to secret milk which the puggle licks up rapidly.
The baby puggle stays in its mother's pouch for about 3 months. During this time the female may remove the baby puggle form its pouch and leave the puggle in a special nursery burrow its made while she goes out to forage for food. Once the puggle's spines have begun to develop its mothers, no doubt finding it uncomfortable, encourages the puggle to spend more and more of its time outside the pouch. When the puggle is about 200 days old, the mother will feed it one last time, dig out its nursery burrow opening and leave the young puggle to fend for itself. She will not return to the burrow again.
Echidna Swimming Can Echidnas Swim?
Echidnas are good swimmers. They are known to journey to their favourite watering-holes for an occasional dip. The echidna actually swims with its head underwater, only lifting its beak above water when it need to take a breath. Like most quadrupeds (four legged animals) the echidna uses a dog paddling stroke.
Echidna's Defences How the Echidna Protects Itself from Predators
The echidna is a shy non-aggressive animal that avoids confrontation. If threatened it has a number of defensive tactics.
The echidna's speckled brown colour allows it to blend in very well with its environment. Furthermore, if it notices a threat it can stay motionless for long periods of time making it even more difficult to detect.
If it is confronted while on a hard surface which it cannot dig into, the echidna’s may try to nonchalantly waddle away at full speed. Unfortunately it is not a very fast runner.
Rolling up into a Ball
Its next strategy is the curl up into a spiky ball protecting its underbelly, head and tail and exposing only its spines to its assailant. Very few predators would attempt to attack the echidna in this pose.
Digging to Bury Itself
The echidnas favorite defensive tactic is to use its powerful claws to dig itself into the ground, until it is completely covered by soil or to firmly embed itself into the soil so that it is difficult for any predator to dislodge it.
An Excerpt from the Original TrishansOz Page
An echidna is about 50 cm long and it is dome-shaped. It has short sharp spikes covering its body (like a porcupine). It has a short pointy snout and a sticky tongue with which it catches ants and termites. It has no teeth. The echidna has very sharp claws too and can burrow underground very quickly. An echidna has short stubby feet and waddles when it walks.
When it gets frightened it raises its spikes to defend itself and tries to dig itself into the ground.
Echidnas adapt their activity according the climate they are in. In hotter climates they are nocturnal, coming out only during the cooler hours of the night. In cooler climates they more diurnal, coming out during the day to forage for food.
You can see how the echidna is trying to hide in the photograph.
My dog Sage once tried to catch an Echidna and hurt his tongue.
The echidna is quite common and not considered threatened. It is protect by Australian law.
Mutiny on the Bounty and the Echidna How are They Related?
The first European to describe the echidna was, in fact, none other than William Bligh, the captain of the sailing ship the HMS Bounty of Mutiny on the Bounty fame. The Bounty was on its way to Tahiti in 1792 when it stopped at Adventure Bay in Tasmania. There Bligh reported that the animal had a bill like a duck and a thick brown coat of hair with quills. A member of the crew shot an echidna and later roasted it, reporting that it had a "delicious flavour".
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