Echidna or Spiny Anteater

Echidna or Spiny Anteater is the name given to two species of animals found in Australia, Tasmania and New Guinea.

The much better known of these is Tachyglossus Aculeatus, (Which means "fast-tongued, spiny", pictured at left), also known as the "short-beaked echidna." It is a medium sized animal, about a foot long and weighing around 15.4 pounds, females are somewhat smaller, with a smallish head attached to a stocky body, and a long cylindrical snout. Its color varies from blond to black, but darker colors are more common. The echidna is covered on its back and sides with stout spines mixed with bristly hair, and superficially resemble a large hedgehog. It is common throughout Australia and Tasmania. It is much less common in coastal areas of New Guinea.

A second species of Echidna is given the scientific name Zaglossus Bruijni (Zaglossus means "Great Tongue", Bruijni refers a Dutch trader who collected the first known specimen; pictured at right), also called the "Long-beaked Echidna." It is considerably bigger that Tachyglossus, growing as large as 36.3 pounds, and has a longer snout curving downwards. The spines tend to be shorter than on Tachyglossus, and are often almost wholly concealed by fur, except along the flanks. Its legs are longer than in its more rotund short-beaked cousin, and it is sometimes described as more pig-like. It is found only in highland regions of New Guinea, and is quite rare. Experts view it as vulnerable to extinction. Unfortunately, very little is known about Zaglossus's biology, behavior or ecological role.

Echidnas are members of the Monotreme, one of the three great orders of mammals. Monotremes are mammals that lay eggs, and have only one external opening, called a cloaca, through which all waste matter and reproductive substances pass. (The word Monotreme means "one opening.")

The other two types of mammals are Marsupials, like the Kangaroo, which give live birth to very underdeveloped young that then must develop in a pouch, and Placentals, which, like Human Beings, have developed methods to give birth to fairly well developed live young.

Besides the Echidna, the only other living Monotreme is the Duck-Billed Platypus (pictured at right), also native to Australia and Tasmania, which is therefore the Echidna's closest living relative. Echidnas vary in appearance, generally with climate. Echidnas in northern warmer zones tend to have more spines, while those in colder climates farther south tend to have more fur. The Tasmanian version of the Echidna has so much fur; the spines only show through on the flanks. Attempts have been made to classify echidnas into various subspecies based on this feature, and other attributes, like the relative size of the different toes. However, today most experts agree that the variation from one population to another is a smooth transition and creating subspecies barriers is a very artificial process. Echidnas also vary in color, the predominant shades being black or dark brown, but "blonde" are also not uncommon, and are frequently mistaken for Albinos, which they are not. The Echidnas of Kangaroo Island, off South Australia, are predominantly blonde.

Echidnas are exceedingly long-lived for their size. One captive Echidna is documented to have lived at least 49 years. Compared to say, a cat, which is of similar mass, this is simply ancient. This is another sign of the essential difference of Echidna's from other mammals

Echidnas, very rarely, can make a sort of cooing sound, like a dove. Echidna tongues are 15-18 centimeters long and oval in cross section, they can shoot out of the tiny mouth with lightening speed and be bent in U-shapes to follow ant tunnels. The tongue is coated with a secretion with the consistency of treacle. Prey sticks to the tongue, and then is removed in the mouth by spines that line the roof. The Echidna has no teeth; food is ground up with special hard pads on the pack of the tongue and top of the mouth. Echidnas live in some areas where there is no water available at least part of the year, and is something of a puzzle how they get their water. It has been calculated that it might be possible for echidnas to get the minimum water they need from their food. Echidnas have also been observed to use a common trick of desert animals, namely licking the early morning dew from plants. Echidnas show greater variation in body temperature than do other mammals, depending on activity levels and air temperature. Their body temperature never exceeds 34 degrees Celsius, the lowest of any mammal. Echidna metabolic rates, measured as oxygen consumption per unit weight under conditions of inactivity, is also the lowest of all mammals (except the platypus.) After mating, there is approximately a 21 to 28 day gestation period before an egg is laid. After about 10 days, the Echidna hatchling emerges from the egg with the aid of a single egg tooth and a carbuncle, a hard bump on its nose. Both the egg tooth and the carbuncle disappear after hatching, but the egg tooth is the only tooth any echidna ever has.

The hatchling is semi-transparent and 13-14 millimeters long at birth. Once hatched, the echidna young, termed a "puggle", remains in the pouch and receives milk from two milk patches towards the front end. Echidna milk is a fascinating substance. First of all it contains almost none of the milk sugar, lactose, which is most important in all placental and marsupial mammal milk. Instead it has completely different sugars, fucosyllactate and syalyllactose. This means that Echidnas cannot digest milk from other mammals and should never be fed milk in captivity. In addition, echidna milk, early in lactation, is pink in color, due to high iron content. It also grows thicker as the young echidna gets bigger, going from quite dilute to over 50% solids by the time the young is weaned.

http://yoyo.cc.monash.edu.au/~tzvi/Echid_I.html