Sunday, July 22, 2007
Long-beaked Echidna
The echidnas and the duck-billed platypus differ from all other mammals in that they lay shell-covered eggs that are incubated and hatched outside of the body of the mother. A female long-beaked echidna usually lays 1 egg into its pouch. The eggs of the long-beaked echidna are soft-shelled and hatch after 10 days, whereupon the young remain in a pouch, dependent on the mother's milk for about 6 months.
The long-beaked echidna lives only in New Guinea. Listed in appendix II of CITES, Z. bruijnii is categorized as vulnerable by IUCN. Hunting with trained dogs by the New Guinean people as well as loss of natural forest habitat due to farming are the primary causes for the species' endangerment. Data tabulated in 1982 indicated that only 1.6 Zaglossus existed per square kilometer of suitable habitat. If the data were accurate, about 300,000 long-nosed echidnas were in existence then, and the number has dropped since that time.
The long-beaked echidna has declined greatly in numbers where it interacts with man, and it is found only where human population densities are low. The major reason for its decline appears to have been traditional hunting - it is a highly prized game animal. Current threats include hunting with specially trained dogs and loss of forest habitat to logging, mining and farming.
Long-nosed echidnas primarily inhabitat mountain forests, although some live on highly elevated alpine meadows. The species does not live along the coastal plains.
The long-beaked echidna weighs 6 - 16 kg (average 9 kg) (13 - 35 lb (average 20 lb)). It has spines of varying length interspersed with fur on its back, sides and tail. The snout is tubular with a very small mouth, through which the long tongue can be rapidly extruded and retracted. Its lack of teeth is compensated for by rows of "spikes" (horny teeth-like projections on the tongue). It is found in humid montane forests on New Guinea and is mainly nocturnal, feeding on earthworms and other invertebrates on the forest floor. It shelters in hollow logs, cavities under roots or rocks, and burrows. Termites and other insect larvae are also eaten, they may eat ants. They are remarkably long-lived, sometimes living for 30 years in captivity.
The long-beaked echidna is found in New Guinea [ (Irian Jaya) and Papua New Guinea ], where it is widespread. However, it appears to be extinct in large areas of the Central Highlands, and it is absent from the trans-Fly plains and from most of northern New Guinea at altitudes below 1200m elevation, as well as all of the North Coast Range.
The front of the long-beaked echidna's tongue is equipped with "spikes" located in a groove. The echidna probes with its long beak until the end of a worm is found. The tongue is then extruded and the worm hooked by these spikes. The worm and tongue are then withdrawn and the worm swallowed by muscular action of the tongue.
The spines on its body can be erected and its arms and legs withdrawn, as a hedgehog does.
The long-beaked echidna is insectivorous. Its diet consists almost exclusively of earthworms. Ants, termites and other worms are also eaten.
The long-beaked echidna is primarily nocturnal. It forages on the forest floor and is a powerful digger. In southern Chimbu, local people say that the long-beaked echidna digs short, shallow burrows with no nesting material inside.
Interesting Fact: Long-beaked echidnas are very inquisitive creatures and somewhat unafraid. They sometimes make a soft, snorting sound. "The echidnas possess some remarkable features. Perhaps most striking is their extraordinarily large and complex brains and relatively high intelligence, characteristics entirely unexpected in the world's most reptile-like mammals." (Flannery 1995)
As monotremes, the long-nosed echidnas possess one body cavity for the external openings of their urinary, digestive, and reproductive organs. The species has a very short tail relative to its average body length of 450-775 mm. The core body is covered in course brown or black hair that often hides the spines covering the back. Zaglossus has a pronounced downcurved snout, which accounts for two-thirds of the length of its head. Lack of teeth in the species is compensated by rows of spikes/horny teeth-like projections on the enormous tongues of the animals. Long-nosed echidnas generally have clawed feet, the front ones important in digging for food. Within the species there is variation in the number of clawed digits on each foot. Many have claws only on the middle three of the five digits present; others have claws on each digit. The males of the species can be distinguished from the females by the presence of a spur on the inner surface of each hind leg near the foot.
Little is known about reproduction in the long-beaked echidna, although they are believed to be similar in reproductive pattern to their sister species, the short-nosed echidna (Tachyglossus aculeatus). Frequency of breeding, courtship rituals, and possible male parental care are unknown for both echidna species. It is thought that the breeding season for the long-nosed echidna is around July. As with reproductive aspects of the biology of long-nosed echidnas, their behavior and social systems are largely unknown. They are believed to be solitary.
The diet of the long-beaked echidna consists almost exclusively of earthworms. When earthworms are eaten, they are positioned by the echidna to go front first into the snout. The powerful tongue of the long-nosed echidna protrudes a small distance and wraps around the front of the worm. While the worm is pulled into the mouth, the echidna's tongue holds the worm in place with its spikes.
The long-nosed echidna is reported to have sweat glands spread over its entire body surface.
Pleistocene fossils of Zaglossus have been found throughout Australia and Tasmania. No other member of the genus currently occurs outside of New Guinea. It is thought that the disappearance of long-nosed echidnas in Australia was due to climate changes that led to decreased presence of earthworms.
In the past, taxonomists recognized up to four species of Zaglossus. At present all long-nosed echidnas are considered to be one species, Z. bruijnii (Augee, 1993; Walker, 1991).
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