Wallaby joeys and platypus puggles are tiny and undeveloped when born. But their mother's milk is near-magical

• But one of the most interesting is we all feed our newborns with milk.
• But our country is far better known for our marsupials and monotremes, which have different reproductive strategies to placental mammals.
• Their milk not only supplies nutrients for sustenance, but also has factors essential for growth and immunological protection.
• 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.

It can be a fight to find a teat

• These specialised glands evolved 166–240 million years ago and have diversified into a wide range of sizes and shapes.
• For marsupials, the number of teats equates to the number of mammary glands.
• 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.

So what’s in their magic milk?

• As the joeys and puggles get bigger, it becomes more concentrated, with more protein and fat.
• Interestingly, iron levels in marsupial and monotreme milk are three times higher than in placental mammal milk.
• Macropod (big foot in Latin) marsupials like kangaroos and wallabies are capable of an even more remarkable feat.

Producing milk takes effort and energy

• When their offspring are a bit older, the mother leaves them alone and goes on a hunt for ants and termites.
• More milk means faster growth rates for the young.
• Marsupial and monotreme milk also provides essential nutrients and additional factors required to support growth.

Milk, the immunological superhero

• All mammals produce colostrum in their milk in the first few days of lactation.
• This milk often looks different, because it contains billions of antibodies to help defend the newborn.
• In marsupials, milk carries antibodies as well as immunological cells from the mother.