VIDEO: Echidna hatching
This 1974 clip from the CSIRO shows a newly hatched echidna puggle emerging.
This 1974 echidna hatching from the CSIRO archives proves that puggles are by far the most adorable native Australian animal.
From egg to prickly adult
About three weeks after mating, the female echidna lays a single, grape-sized egg into a simple pouch that has developed on her abdo-men a short time before.
The rubbery, cream-coloured egg has to be moved to the pouch from the cloaca, the single opening through which pass faeces and urine as well as eggs.
The echidna probably does this by contorting her body while lying on her back. About 10 days later the 15-millimetre-long embryo hatches, blind, hairless and virtually helpless, and sucks a low-fat milk from nipple-like structures in the pouch.
After about 50 days, when the baby weighs about 200 to 400 grams and its spines are sprouting, the mother drops it into a concealed burrow, where she feeds it once every five to 10 days with milk now rich in fat.
By the time the young echidna leaves its nursery burrow six to eight months later its spines are well developed. The echidna, more correctly called the short-beaked echidna to distinguish it from the long-beaked echidna, its larger New Guinean relative, is a mono-treme, which means one hole - referring to the cloaca.
The long-beaked echidna became extinct in Australia about 20,000 years ago. To feed, the echidna breaks into ant or termite nests with its powerful fore-paws and traps the insects on its sticky, 18-centimetre-long tongue.
These are drawn into the mouth and ground to a paste between the palate and a horny pad at the base of the tongue, the echidna having no teeth. Up to 40 per cent of the echidna's body weight is fat, enabling it to go without eating for many days, even weeks. Spines sprouting on a 56-day-old echidna.
After hatching, the young echidna stays in its mother's pouch for up to 63 days. When the spines appear, the mother places it in a nursery burrow.
Nestling in the pouch, this egg has developed a dimple, a sign that it is about to hatch. The pouch forms when the echidna becomes pregnant. About three weeks later, she lays her egg into it.