Monotremes and marsupials produce different milk at different stages of lactation.Įarly on, their milk is more dilute. Author provided So what’s in their magic milk? The red-tailed phascogale ( Phascogale calura) – a tree-living insect eating marsupial – can give birth to up to 13 young but females only have eight teats.Ī gray short-tailed opossum ( Monodelphis domestica) showing pouch young attached to teats. In some species, the first hours are brutal as more young can be born than there are teats for them, and only those able to latch on in the first few hours can survive. Newborn marsupials have to seek out and firmly attach themselves to the teat. Some animals pause their own pregnancies, but how they do it is still a mysteryĪs you’d expect, teat numbers align with the maximum number of young a marsupial mother can sustain. The highest number of mammary glands recorded in a marsupial is 13, in the gray short-tailed opossum ( Monodelphis domestica), while the largest surviving marsupial, the red kangaroo ( Osphranter rufus), only has four teats. The larger the marsupial, the fewer teats they have. For marsupials, the number of teats equates to the number of mammary glands. While marsupials have teats for their joeys to suckle from, monotremes have milk patches which secrete milk directly onto the pigmented skin of the areola where their baby puggles can lap the milk from the pores. These specialised glands evolved 166–240 million years ago and have diversified into a wide range of sizes and shapes. It can be a fight to find a teatĪll mammals possess mammary glands. Their milk likely has chemicals serving to attract newborns to the teat even though they have very little sensory or movement ability at this stage.Įchidnas and platypuses lay eggs, which hatch revealing underdeveloped puggles. Their milk not only supplies nutrients for sustenance, but also has factors essential for growth and immunological protection. To overcome this, female marsupials and monotremes produce truly remarkable milk. Most of their development happens outside the womb or egg. When a wallaby gives birth to a tiny pink joey, it’s the equivalent to us giving birth to an eight week old foetus. ![]() Marsupials, too, give birth to underdeveloped young. When an echidna egg hatches, the baby is very underdeveloped. Monotremes are the only mammals to lay eggs. The other three echidna species live on the island of New Guinea. We have around two-thirds of all living marsupial species, and two of the five remaining monotreme species on the planet – the platypus ( Ornithorhynchus anatinus) and short-beaked echidna ( Tachyglossus aculeatus). But our country is far better known for our marsupials and monotremes, which have different reproductive strategies to placental mammals. In Australia, we have many placental mammal species, like bats and native rodents. The word mammal comes from mamma, which is Latin for breast. But one of the most interesting is we all feed our newborns with milk.
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