Biology today

Table : important examples of mammals

Scientific name Common

name

important notes

Monotremata

1. Tachyglossus or
   Echidna

Australian

spiny

anteater

•    It is found throughout Australia and Tasmania.

•    The body is covered with strong pointed spines (modified hair).

•    Feet are without webs.

•    Teeth are absent in adult.

•    Male Echidna also has a hollow tarsal (horny) spur on each hind leg connected

to a poison gland in the thigh.

•    Female Echidna usually lays only one egg. Male Echidna also has mammary

glands secreting milk to feed the young. This condition is known as

gynaecomastism. Teats are absent.

•    Spiny anteater can roll itself into a ball to surprise the attacker.

2. Ornithorhynchus Duck-billed
   platypus

•    It is found in Australia, including Tasmania.

•    It lays eggs in the nests.

•    The beak or bill is broad and flat just like a duck, hence named as duck-billed

platypus. Both the webbed feet and flattened tail help in swimming.

•    Pinnae are absent.

•    Mammary glands are present, but nipples or teats are absent.

•    Male can be distinguished from the female as the male has a poisonous spur on

each hindlimb. These spurs mark sexual dimorphism.

Marsupialia

3. Didelphis Opossum • Tree dwelling marsupials confined to America.
   • Body covered with a coarse fur.
   • Legs are much shorter, snout is elongated and large black eyes shine in its white
   face.
   • It is nocturnal, arboreal, omnivorous and very destructive.
   • When suddenly disturbed, it may froth at the mouth and feign death.
   • Their gestation period is the shortest for any mammal, 12 to 14 days only.


4. Macropus Kangaroo • It is a native of Australia, Tasmania and neighbouring islands.
   • Female kangaroo has a marsupial pouch (marsupium) in which the immature
   young ones are fed by the mother.
   • Long thick stout tail makes a tripod with hindlimbs.
   • The leather of the kangaroo is water proof.
   • Usually a single offspring, immature, naked, about 3 cm long, is born. It is fed
   on milk inside the marsupium, enclosing teats of mammary glands, to complete
   development in about 4-6 months.
   • Kangaroos are mostly terrestrial, gregarious and herbivorous animals causing
   great harm to the growing crops. They are also hunted for flesh, fur and sport.


5. Phascolarctos Koala • It is an arboreal marsupial, living and feeding on the eucalyptus forests of
   eastern Australia.
   • It has woolly fur, large ears, a soft pad on nose, rudimentary tail, cheek pouches
   and enlarged caecum.
   • The female first carries young in a posteriorly opening abdominal pouch, and
   later on her back.