Echidna

Echidna Monotreme: A Spiny Anteater

Monotremes, together with placentals (Eutheria) and marsupials, are one of the three major groupings of extant mammals (Metatheria). When compared to more common mammalian kinds, monotremes have anatomical differences in their brains, jaws, digestive tract, reproductive tract, and other body parts. Furthermore, rather than bearing live young, female monotremes lay eggs, yet, like all mammals, they nurse their young with milk.

Prototheria is the old name for the mammalian subclass Monotremes. Although there is evidence that monotremes were previously more widespread, including some extinct species in South America, the few living examples are all endemic to Australia and New Guinea. The platypus and four echidna species are the only monotremes that exist today. Monotreme taxonomy is currently a point of contention.

Characteristics of Monotreme 

• Monotremes, like other mammals, have a fast metabolic rate (albeit not as high as other mammals) hair on their body; milk produced by mammary glands to nourish their young; a single bone in their lower jaw; and three middle-ear bones.

• Monotremes, like reptiles and marsupials, lack the connective structure (corpus callosum), which is the principal communication channel between the right and left brain hemispheres in placental animals.

• Monotremes do not have teeth. One of the trademarks of extant mammals is the "tribosphenic" type of molars (with the occlusal surface formed by three cusps grouped in a triangle), which is found in both fossil forms and present platypus young. Recent research implies that monotremes developed this type of molar independently of placental animals and marsupials, while this theory is still controversial. The evolution of electrolocation in modern monotremes may be linked to tooth loss.

• The jaws of monotremes are built differently than those of other mammals, as is the jaw opening muscle. The tiny bones that conduct sound to the inner ear are fully incorporated into the skull in all true mammals, rather than lying in the jaw as they are in cynodonts and other pre mammalian synapsids; this feature, too, is now claimed to have evolved independently in monotremes and therians, though this hypothesis, like the analogous evolution of the tribosphenic molar, is disputed. Nonetheless, research on the extinct Teinolophos demonstrates that monotremes and therians evolved suspended ear bones independently.

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Reproduction of Echidna Monotreme

• Monotremes get their name from a significant physical distinction between them and other mammals: monotreme means "one opening" in Greek, alluding to the single duct (cloaca) that houses their urine, defecatory, and reproductive systems. Monotremes, like reptiles, have a single cloaca. Most placental mammalian females have distinct entrances for reproduction (the vagina), urination (the urethra), and faeces (the urethra) in comparison to marsupials (the anus). Only semen travels through the penis in monotremes, whereas urine is expelled through the male's cloaca. A preputial sac covers the monotreme penis, which is identical to that of turtles.

• Monotreme eggs are kept within the mother for a length of time and acquire nutrition straight from her, hatching within 10 days of being laid — a far shorter timeframe than sauropsid eggs. Newborn monotremes, sometimes known as "puggles," are similar to newborn marsupials (and maybe all non-placental mammals) in that they are larval and fetus-like, with reasonably well-developed forelimbs that allow them to crawl around. Puggles crawl around more frequently than marsupial joeys in search of milk since monotremes lack nipples, raising issues about the assumed developmental constraints on marsupial forelimbs.

• Monotremes lactate from their mammary glands through skin openings rather than nipples. With modest rates of reproduction and generally lengthy life spans, all five surviving species provide extended parental care to their offspring.

• The zygotic development of monotremes is also noteworthy: The ovum breaks into several, divisible daughter cells in most mammalian zygotes during holoblastic cleavage. Monotreme zygotes, on the other hand, such as those found in birds and reptiles, go through meroblastic (partial) division. This means that the cells near the yolk's edge have cytoplasm that is continuous with that of the egg, allowing the yolk and embryo to exchange waste and nutrients with the cytoplasm in the surrounding area.

• By mammalian standards, monotremes have a very slow metabolic rate. The platypus's typical body temperature is around 31 degrees Celsius (88 degrees Fahrenheit), compared to 35 degrees Celsius (95 degrees Fahrenheit) for marsupials and 37 degrees Celsius (99 degrees Fahrenheit) for placental animals. According to research, rather than being a general characteristic of defunct monotremes, this was a progressive adaptation to the hard, marginal environmental niches in which the few remaining monotreme species have managed to survive.

• Although monotremes have less developed thermoregulation than other mammals, new research suggests that they can readily keep a consistent body temperature in a variety of situations, such as platypus in frigid alpine streams. Early researchers were misled by two factors: first, monotremes have a lower average temperature than most mammals; second, unlike the reclusive platypus, the short-beaked echidna maintains a normal temperature only when active; in cold weather, it conserves energy by "switching off" its temperature regulation. Reduced heat regulation was noted in hyraxes, which are placental mammals, which led to the discovery of this mechanism.

Echidna Monotreme

The echidna was assumed to have no rapid eye movement sleep at first. However, a more recent study found that at a temperature of 25 °C (77 °F), REM sleep accounted for roughly 15% of the sleep time recorded in individuals. The study found very minimal REM at low temperatures of 15 °C (59 °F) and 20 °C (68 °F), as well as a significant drop at high temperatures of 28 °C (82 °F).

Platypus Echidna

• Monotremes are traditionally classified as a single order, Monotremata, however, a recent classification proposes splitting them into the orders Platypoda (the platypus and its fossil ancestors) and Tachyglossus (the platypus and its fossil relatives) (the echidnas, or spiny anteaters). The entire grouping is also usually assigned to the Prototheria subclass, which was later expanded to include many fossil orders, but they are no longer considered to be monotreme ancestors. The monotremes are now linked to a separate collection of prehistoric mammals known as Australosphenida, according to a disputed theory.

• Spurs can be found on the rear limbs of platypus and echidna species. The platypus spurs contain venom, whereas the echidna spurs are vestigial and have no known function. Molecular evidence suggests that the major component of platypus venom evolved prior to platypus and echidna divergence, implying that the most recent common ancestor of these taxa was a venomous monotreme.

Fossil of Monotreme 

Monotremes have a relatively limited fossil record. Steropodon galmani, discovered at Lightning Ridge, New South Wales, was the first Mesozoic monotreme ever discovered. Although biochemical and anatomical evidence suggests that monotremes separated from the mammalian lineage before marsupials and placental mammals appeared, just a few monotreme fossils from before the Miocene period have been discovered. Steropodon and Teinolophos are the only Mesozoic monotremes known, and they all come from Cretaceous Australian strata, indicating that monotremes had already evolved.

One theory is that monotremes developed in Australia in the Late Jurassic or Early Cretaceous, and that some moved through Antarctica to South America, both of which were still unified with Australia at the time. However, other genetic analyses imply a beginning in the Triassic.

Echidna Spiny Anteater

Echidnas, sometimes known as spiny anteaters, are members of the monotreme order of egg-laying mammals and belong to the Tachyglossidae family. The platypus and four extant echidna species are the only living mammals that lay eggs and the only remaining members of the Monotremata order. Some species consume ants and termites, but they are not related to the real anteaters of the Americas, which are classified as xenarthrans together with sloths and armadillos. Echidnas can be found in Australia and Papua New Guinea.

Echidnas descended from a platypus-like monotreme between 20 and 50 million years ago. Although its origin was aquatic, echidnas evolved to live on land.

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Scientific Classification of Echidna Spiny Anteater

Kingdom: Animalia

Phylum: Chordata

Class: Mammalia

Order: Monotremata

Suborder: Tachyglossa

Family: Tachyglossidae

Characteristics of Australian Spiny Anteater

• They resemble South American anteaters as well as other spiky animals like hedgehogs and porcupines. They are usually dark brown or black in colour. There have been some sightings of albino echidnas with pink eyes and white spines. Their elongated, narrow snouts serve as both a mouth and a nose. They have electro sensors, however, unlike the platypus, which has 40,000 electroreceptors on its bill, the long-beaked echidna only has 2,000. The short-beaked echidna, which prefers a drier climate, has only 400 teeth at the tip of its nose. Echidnas detect earthworms, termites, ants, and other burrowing prey via their electroreceptive beaks.

• Echidnas are powerful diggers with short, muscular limbs and huge claws. To aid in digging, the claws on their rear limbs are extended and bent backwards. Echidnas have toothless jaws and tiny mouths. The echidna eats by tearing up soft logs, anthills, and other soft materials and collecting prey with its long, sticky tongue that protrudes from its nose. Ears are apertures on the sides of their heads that are generally hidden because their spines cover them. A huge cartilaginous funnel deep in the muscle forms the external ear. The echidna has the second-lowest active body temperature of all mammals, after the platypus, at 33 °C.

Diet of Spiny Anteater 

The Zaglossus (long-beaked) echidna eats worms and insect larvae, whereas the short-beaked echidna eats mostly ants and termites. Long-beaked echidnas have sharp, microscopic spines on their tongues that assist them to catch their meal. Because they lack teeth, they crush their food between the bottoms of their mouths and their tongues to break it down. Echidna faeces are cylindrical in shape and 7 cm (3 in) length; they are frequently fragmented and unrounded, and are mostly dirt and ant-hill detritus

Habitat of Spiny Anteater 

Echidnas cannot withstand severe temperatures and seek refuge in caves and rock crevices. Echidnas can be found lurking behind plants, roots, or heaps of trash in forests and woodlands. They have been known to use the burrows of animals like rabbits and wombats. Individual echidnas have huge areas that overlap.

Anatomy of Spiny Anteater 

Monotremes, which include echidnas and platypus, are the only egg-laying mammals. An echidna's average lifespan in the wild is estimated to be 14–16 years. A female can weigh up to 4.5 kilogrammes (9.9 lb) and a male up to 6 kilogrammes when fully grown (13 lb). The sex of echidnas can be deduced by their size, with males being 25% larger than females on average. Both sexes have a single hole called a cloaca, which they utilise to urinate, expel their faeces, and mate. On the hind feet of male echidnas are non-venomous spurs.

Reproduction of Spiny Anteater 

• After mating, the female lays a single soft-shelled, leathery egg that she inserts directly into her pouch 22 days later. An egg is around 1.4 centimetres (0.55 in) length and weighs 1.5 to 2 grammes (0.05 to 0.07 ounce). The infant echidna uses a reptile-like egg tooth to crack open the leather shell as it hatches. After a ten-day gestation period, the young echidna, known as a puggle, is born as a larval and fetus-like echidna that sucks milk from the pores of the two milk patches (monotremes have no nipples) and remains in the pouch for 45 to 55 days, when it begins to develop spines.

• Echidnas have a four-headed penis in males. One side of the head "shuts down" and does not develop in size during mating; the other two are employed to deliver semen into the female's two-branched reproductive canal. When it copulates, it alternates the heads in pairs. The penis is retracted inside a preputial sac in the cloaca while not in use. When erect, the male echidna's penis is 7 centimetres (2.8 in) in length, with a shaft covered in penile spines. These could be used to get a woman to ovulate.

• It's difficult to study the echidna in their natural environment, and they don't seem interested in mating in captivity. No one had ever observed an echidna ejaculate until 2007. Previous attempts to induce the echidna to ejaculate using electrically stimulated ejaculation in order to gather semen samples failed because the penis swelled. The breeding season starts in late June and lasts until September. Males will form ten-person lines to pursue the female and seek to mate, with the youngest echidna trailing last. An echidna may swap lines during the mating season. The "train" system is what it's called.

Threats of Echidnas 

Echidnas are fearful creatures. When they are threatened, they will try to bury themselves or roll up into a ball like a hedgehog, both ways relying on their spines to protect them. Echidnas have strong front arms that allow them to continue digging while fending off predators attempting to pull them out of the hole.

Despite their ability to defend themselves, echidnas nevertheless face numerous threats. Feral cats, foxes, domestic dogs, and goannas are some of the predators. Snakes slide inside echidna burrows and feast on the young spineless puggles, posing a serious threat to the species.

Facts About Echidna 

1. Hairs 

Hairs make up their spines.

The spines on an echidna, believe it or not, are actually long, strong, hollow hair follicles.

When predators attack, an echidna's spines are its main line of defence. They will curl up into a ball of radiating spines to protect themselves or dig themselves to safety if they are threatened.

In addition to their spines, echidnas have shorter fur to keep them warm.

2. Spine

They have a variety of coloured spines.

Echidnas in South Australia are substantially darker in colour than their counterparts in the eastern states.

Echidnas from southeast Queensland, for example, are much lighter and can nearly appear to have "blonde highlights" due to the year-round sun! Kangaroo Island has been home to pure white and even red-headed echidnas.

3.Eggs 

They produce eggs.

The echidna is the only other live egg-laying mammal species, along with the platypus.

The female lays a single soft-shelled, leathery egg in her pouch almost a month after mating. The gestation period is short, with the young echidna hatching after only ten days.

Puggle echidnas are young echidnas. They may stay in the den their mother builds for up to a year before venturing out on their own.

4. Tooth

Echidnas are toothless mammals, but their lengthy, sticky tongues more than compensate for this. We mean it when we say long. We're talking about a difference of 15 cm.

Their tongues are extremely fast, allowing them to slurp up ants, worms, and insect larvae with ease. Tachyglossus, the scientific name for the echidna, literally means "quick tongue" — a perfect name!

Conclusion

Monotremes are one of the three major groups of extant mammals, along with placentals (Eutheria) and marsupials (Metatheria). Monotremes feature anatomical changes in their brains, jaws, digestive tract, reproductive tract, and other body parts when compared to more common mammalian species. Female monotremes also lay eggs rather than bear live young, but they, like all mammals, suckle their young with milk.

The mammalian category Monotremes was once known as Prototheria. Although there is evidence that monotremes were once more common, including some extinct species in South America, monotremes are now only found in Australia and New Guinea.

Echidnas, sometimes known as spiny anteaters, are members of the Tachyglossidae family, which belongs to the monotreme order of egg-laying mammals. The platypus and four extant echidna species are the only remaining members of the Monotremata order and the only living mammals that lay eggs. Although some species feed ants and termites, they are unrelated to the true anteaters of the Americas, which are categorised as xenarthrans along with sloths and armadillos. Australia and Papua New Guinea are home to echidnas.