einisäkkäät

Einisäkkäät, known scientifically as Monotremata, are a unique order of mammals that lay eggs instead of giving birth to live young. This ancestral trait sets them apart from all other living mammals, the marsupials and the placental mammals. The order currently comprises only five species, all native to the Australian region.

The most recognizable einisäkkäät are the echidnas, also called spiny anteaters. There are four species of echidnas: the short-beaked echidna and three species of long-beaked echidnas. These creatures are characterized by their spiny coverings and long snouts, which they use to forage for ants and termites.

The other extant member of the einisäkkäät order is the platypus. This semi-aquatic mammal is famous for its duck-like bill, beaver-like tail, and otter-like feet. The platypus is a venomous mammal, with the male possessing a spur on its hind leg capable of delivering a potent toxin.

A key characteristic of einisäkkäät, besides egg-laying, is the presence of a cloaca, a single opening that serves the urinary, defecatory, and reproductive tracts. Like other mammals, einisäkkäät possess mammary glands to nourish their young. However, instead of nipples, the milk is secreted through pores onto the skin, and the young lap it up from a specialized groove or patch. Despite their reptilian-like reproductive method, they are definitively mammals due to these other defining mammalian features.