8 Apr 2020


To celebrate the Easter weekend, we’re sharing some weird and wonderful facts about egg-laying Aussie animals. Check out our truly egg-cellent animals below...

Echidna (Tachyglossus aculeatus - short beaked echidna)

Echidna in grass
Echidna in grass © Chris Farrell Nature Photography / WWF-Aus

Meet the echidna - spikey, a long snout and a mammal that lays eggs. But there’s so much more to this species than first observed. 

From June to September (breeding season) echidnas like to form an echidna train. This is where two to ten male echidnas follow a female in the hopes of becoming her mate. If a male suspects it won’t be the chosen one, it will leave their current train and join a different one, trying their luck at love with a new mate. 

An adult female echidna usually lays a single egg once a year. The leathery egg is about the size of a grape. The female rolls the newly laid egg into a deep pocket, or pouch, on her belly to keep it safe. Ten days later the baby echidna, called a puggle, hatches.

King brown snake (Pseudechis australis)

Pseudechis australis King brown snake One of the most venomous snakes in the world, Australia
Pseudechis australis King brown snake One of the most venomous snakes in the world, Australia © Martin Harvey / WWF

When you think about animals that lay eggs snakes are often overlooked. Maybe it’s because snakes aren’t as easy to warm to as other creatures (pun intended). But the king brown snake (also known as the mulga snake) has been included in this list because it’s a seriously impressive egg-layer. A female will lay an impressive clutch of about 8-20 eggs all at one time. Once laid, the mother leaves the soft leathery eggs to fend for themselves. If you think that’s harsh, this reptile will eat its own kind. That’s right, other king browns! 

You may be thinking, because of its name, that the king brown is a brown snake but in actual fact, it is a member of the black snake family. 

Emu (Dromaius novaehollandiae)

An emu at Innes National Park on the Yorke Peninsula, South Australia
An emu at Innes National Park on the Yorke Peninsula, South Australia © Balambigai Balakrishnan / WWF-Australia

What the emu lacks in flight it makes up for in speed. It’s long, powerful legs can propel it forward at a speed of up to 50km/h. 

As the world’s second-largest bird it’s no surprise that females produce large eggs. These big beauties are emerald in colour, making them one of the world’s most attractive eggs. Plus, they have three layers - the outside is green, the middle is teal, and the inside layer’s nearly white. Once this big egg’s been laid the female moves on, sometimes to mate with another partner, while the male stays to incubate the egg. He does this for seven weeks without drinking, feeding, defecating, or leaving the nest. Now, that is impressive!

Saltwater crocodile (Crocodylus porosus)

Saltwater crocodile on the Daly River in the Northern Territory.
Saltwater crocodile on the Daly River in the Northern Territory. © Stuart Blanch / WWF-Aus

The ‘saltie’ as Australians affectionately call them, are the animals most likely to eat you. But they’re not fussy, they’ll feed on anything they can get their jaws on, including water buffalo, monkeys, turtles, snakes, and even sharks. They lie in wait, patiently, and then burst from the water, grab their victim, and drag it down, holding it under until the animal drowns.

The saltwater crocodile builds a nest usually made of mud and plant matter and lays around 50 eggs at a time. Believe it or not, like a sea turtle, the temperature of the nest will determine the sex of the crocodile - if it’s around 31.6°C, all eggs will hatch as males. Below or above that temperature, the crocodile eggs will hatch as females. Interesting stuff!

It takes around 75 days for crocodile eggs to hatch but only 1% of those are thought to survive maturity in the wild.

Black swan (Cygnus atratus)

Black swan (Cygnus atratus) on water with baby
Black swan (Cygnus atratus) on water with baby © S Hermann & F Richter / Pixabay

You’ll be forgiven for thinking this is a character from a ballet or the title of a great movie. But the black swan is a beautiful bird living in Australia. The birds are entirely black except for the white outer flight feathers of the wings and a deep orange-red beak.

The black swan travels long distances outside the breeding season and flies at night only to rest during the day with the other swans.

Black swans mate for life, raising one brood together per season and usually lay around 10 eggs at a time. 

Hawksbill turtle (Eretmochelys imbricata) 

Hawksbill turtle (Eretmochelys imbricata) swimming through a reef. Kimbe Bay, West New Britain, Papua New Guinea. 31 May 2010
Hawksbill turtle (Eretmochelys imbricata) swimming through a reef. Kimbe Bay, West New Britain, Papua New Guinea. © Jürgen Freund / WWF

Australia has some of the largest remaining nesting populations of hawksbill turtles. There’s no mistaking them, they have a beak-like mouth and a beautiful patterned-shell. Unfortunately, it’s this gorgeous shell (called tortoiseshell) that has made them a target for harvesting by humans and they now face an uncertain future.

Hawksbill turtles’ sharp, pointy beak is used to pick sponges out of cracks and crevices in coral reefs. They mature slowly and may not reach reproductive age until 30 years old. But when they are ready, they get straight to work. They nest every two to four years, laying one to six clutches per season with an average of 122 eggs at a time. After the hatchlings emerge from the nest they swim for several days out into the sea. They then spend approximately five to ten years drifting in the ocean - what a life!

Platypus (Ornithorhynchus anatinus)

Burnie, Tasmania, Australia: March 2019: Platypus swimming in the river
Platypus swimming in the river © WWF-Australia / Lukas - stock.adobe.com

And our last ‘eggcellent’ unique egg-laying species is the ‘duck-billed’ platypus. If you never visit Australia, you’ll never see one, and even then they are incredibly shy and rare to spot. because this semiaquatic mammal is only found in the eastern waterways.

Only found in the eastern waterways the semiaquatic platypus is a unique and treasured Australian gem, being one of the last remaining egg-laying mammals (monotremes) left on Earth. It does look a bit peculiar, a little like Walt Disney drew a duck’s bill onto the body of a mammal. 

Just in case you were thinking of it, don’t ever start with a male platypus - it has a pair of venomous spurs on its back foot, partly for self-defence and partly to exert dominance over it female partner. And after the female has laid her (usually two) eggs and hatched them, he takes no part in the child-rearing at all. These males are clearly still living in the last century! Gestation is at least two weeks and incubation can take up to 10 days. The young suck milk from special mammary hairs and stay protected with the mother for up to 3 months before becoming independent. 

Another fun platypus fact is that these mammals are waterproof!