Question

Which are the mammals which lay eggs?

Answer 1

monotremes are mammals that lay eggs instead of giving birth to young ones.the only egg laying mammals are the platypus and echdina.

Answer 2

Sub-Class Prototheria. Prototherians are considered to be the most primitively type of mammals which are primarily restricted in Australia and its neighbouring islands (Tasmania in New Guinea). Besides egg laying mammals and their main habitats, they have several reptilian characters including a cloaca. They lay eggs containing ample amount of yolk in the egg which acts as a nourishment for the foetus. Sub-class prototheria includes one order Monotremata or called as Monotremes. Example, Ornithorhynchus or Duck-billed platypus and Tachyglossus or Echidna. Unlike their mammalian counterparts they are oviparous (mammals are Viviparous). Except egg laying mammals a well developed placenta is present in mammals and absent in monotremes. Duck-billed platypus contain a spur (in males), a nostril and a beak however, Echidna contain Hairs (which are modified into hard spines), a snout, clawed digits and a horny spur, these were some distinguishes between the latter two.