|
|
|
  |
| Sunday, 13 February 2005 |
 |
|
 |
Junior Observer |  |
| News Business Features Editorial
|
A trio of mammals Mammals evolved from an extinct group of small reptiles some 200 million years ago during the age of dinosaurs. The name 'mammal' is derived from the 'mammary glands' they have. It is from a secretion from these glands that they feed their young. There are three main groups of mammals that are alive today. The primitive egg-laying monotremes, represented by the platypus and the echidna, the more advanced marsupials, now confined mainly to Australia and South America, and the eutherian (or placental) mammals, the group to which most mammal species belong... *** American Opossum - quickest breeder
The opossum is found in lower Canada, down through USA to Mexico in woodlands, usually near water. It feeds on any animal or vegetable matter. It is the only marsupial in North America. The American or Virginian Opossum can produce two litters each year. Born blind, without fur, these tiny opossums must find their way to the mother's pouch on her abdomen to attach themselves to a teat and continue development. More than a third die on their difficult journey from the birth canal to the pouch. The infants possess sharp claws to help them crawl, but they are lost soon after they reach the safety of the pouch. The mother sometimes licks a path for the infants across her fur and occasionally carry some of them in her mouth and place them in her pouch. In appearance, the opossum is like a rat but is the size of a cat. When surprised by would-be attackers, it is famous to feign death. ***** Greater Glider - mammal that flies without wings
Distributed in the coastal highlands of Eastern Australia from Victoria to Queensland, in forests and tall woodlands, a greater glider has been once seen to cover a distance of 550m (590 yards) in six consecutive glides, the longest of which was 110m (120 yds). By climbing to the tops of tall trees, it effortlessly launches itself into a long, shallow dive to the ground. Flaps of elastic skin along its flanks can be stretched into a gliding wing by extending its arms and legs. On the ground however, it is slow and clumsy. The greater glider is also a cat-sized marsupial like the American opossum. It is about 130cm (50 in) in length including the tail which is about 55 cm (20 in) long. Leaves, leaf tips and blossoms of eucalyptus are its diet. It breeds during July-August and the newborns are no bigger than the head of a drawing-pin. Its cry, a shriek, ending in a series of strangled gurgles, is said to sound eerily human at night. **** Platypus - egg-laying mammal
Distributed throughout eastern Australia and Tasmania, the platypus lives in rivers, and lakes from sub-tropical coasts to alpine streams, at 1500m (4900 ft) above sea level. It is a strong and graceful swimmer. It uses its forelimbs to propel itself and its hindlimbs as both stabilisers and rudder. The platypus eats insect larvae, crayfish, tadpoles and worms. It can remain underwater for several minutes by wedging itself under stones or logs, while searching for food in muddy river beds. It locates its food by feel alone using its sensitive duck-like beak. Its ears and eyes are covered by flaps while it is submerged.
A platypus can live for about 10-15 years. One is supposed to have lived upto 17 years in captivity. |
|
|
| News
| Business | Features
| Editorial | Security
| Politics | Produced by Lake House |
With a gestation period of 8-13 days, this opossum holds the record for
being the quickest breeder among the mammals. There are about 10-12 or
more infants per litter and they weigh barely two grams (0.01 oz) each.
The throat and windpipe are separate in the young so that they can drink
and breathe at the same time.
The largest of six species of gliding phalangers or opossums,the
greater glider is known as the mammal that flies without wings.
This mammal that looks like a duck is one of only two groups of animals
that belong to the order montremata. It is one of the most primitive
egg-laying mammals and it is said that when the first specimen was brought
to Europe way back in 1798, it was declared a hoax constructed from the
head and feet of a duck and the body of an otter. The male is about 50-60
cm (20-24 ins) and the female is smaller. It weighs about 2kg.
The female lays leathery-shelled eggs in a grass-lined nest at the end
of a long winding tunnel burrowed into a river bank. After an incubation
period of 10-12 days tiny, naked infants, barely 18 mm (0.7) in length
appear. By the time it leaves its mother's pouch at 17 weeks, it has grown
to a length of 34 cm (13 in). The young have 10 teeth which are later
replaced by horny plates, when they become adults.
