Croc eggs ‘cooked’ in sun as rain comes late in nesting season

Selling crocodile eggs is an important business for remote Indigenous rangers who brave Top End swamps to collect them for farms near Darwin.

Experienced rangers search for eggs by helicopter and buggy or travel by foot into nesting areas.

“We walk in with a pretty big group, try and make as much noise as we can so the animals know we’re coming,” said Djelk Rangers manager Jason Koh.

“You’ve just got to look after each other and watch each other’s back.

Crocodiles nest and lay eggs during the November to May wet season.

But this wet season, it is not just protective female crocodiles that are a challenge for egg collectors.

Mr Koh said larger-than-usual numbers of eggs did not have viable embryos — and he blamed the heat and lack of rain.

“A few of the first nests we visited this season, the eggs have not been fertile,” he said.

“You can tell by the colour of the egg, the banding on the egg, and once we get them back to the ranger base we candle the egg with a torch and you can see if it’s a viable egg.”

Hot season leaves eggs exposed

Indigenous ranger groups can secure permits to gather and trade crocodile eggs.

This season, about 150 out of the 900 eggs collected by the Djelk Rangers near Maningrida, 500 kilometres east of Darwin, have not been fertile.

The first monsoon of the wet season was six weeks later than average, and heatwaves have been all too frequent.

Mr Koh said many of the crocodile nests suffered from the lack of cloudy weather and rain.

“Some of the nests are on the floodplains where there’s not much shade, and they seem to get cooked,” he said.

“Crocodile eggs are pretty sensitive to temperatures.

“If they’re too cold, they end up all females; if it’s 32 degrees [Celsius], they end up males — and they don’t like the temperature going up much more than that.”

Croc populations on the rise

Crocodiles are such an identifiable Australian species that it’s hard to believe they were almost wiped out just 50 years ago.

Protection laws introduced in the 1970s have helped wild populations bounce back, with more than 100,000 saltwater crocodiles now believed to live in northern Australia.

Scientists credit the crocodiles with helping control the growing number of invasive animals in the north.

Charles Darwin University ecologist Hamish Campbell said in the 1970s young buffalo and pigs could wallow around freely.

“Not now, [they’d] get smashed by a 5-metre crocodile,” he said.

Mr Koh said the community in Arnhem Land supported the rangers’ wild croc egg harvesting.

“There’s probably up to 50 eggs in each nest, so that’s 50 crocodiles out of the system.”

Crocodiles are farmed for their leather, which is turned into luxury items for high-end fashion houses, primarily in Europe. 

Meat is a by-product of the process.

‘Good year’ for croc park

At a Darwin wildlife park, where climatic conditions can be controlled, it has been “a really good year” for baby crocodiles.

But Jess Grills from Darwin’s Crocodylus Park said it still took careful monitoring.

“If you’ve got a very hot day and a nest has been laid in the morning, without the rain, it is crucial to get those eggs out straight away,” she said.

“Otherwise, the heat in the nest will overcook the eggs and kill the embryos.”

Through a combination of seasonal luck and the use of egg incubators, the park now has a strong new generation of baby saltwater crocodiles.

“Most of our nests did come pretty early,” Ms Grills said.