Wild crocodiles in Australia keep dying from eating toxic cane toads, so scientists have trained them to avoid the deadly meal by giving them a memorable dose of food poisoning.

Cane toads (Rhinella marina) were introduced to Australia in the 1930s to control agricultural pests in the sugar cane industry, but have themselves become a devastating environmental threat, wreaking havoc with native wildlife as they have spread relentlessly across the continent.

Native predators are naïve to the threat posed by the toads’ toxic glands, which secrete a compound called bufotoxin. Eating these toads is almost always deadly, says at Macquarie University, Australia. “There is no opportunity to have a non-fatal encounter and learn a lesson not to eat them,” she says.

That is certainly the case for freshwater crocodiles (Crocodylus johnstoni), with populations of the animals in some areas of northern Australia collapsing by more than 70 per cent as the first waves of the toads swept through.

Researchers have had some success training some other affected Australian species, including monitor lizards and quolls, not to eat the toads. They do this by removing the toxic glands from the toads and instead infusing them with non-lethal doses of the toxin, causing nausea and making the predators averse to eating them in the future.

Now, Ward-Fear and her colleagues have attempted a similar technique on freshwater crocodiles. The team monitored crocodile populations in four target areas in the Fitzroy Valley region of north-west Western Australia, as the toads approached in September 2021.

They set nearly 2400 baits – removing the toxin from toad carcasses and infusing them with lithium chloride, which is known to induce non-fatal nausea in reptiles. The team also set unbaited chicken necks as a control.

Initially, nearly all the baited toads and unbaited chicken necks were eaten, but within five days, as the food poisoning symptoms spread through the four local crocodile populations, the predators began to wise up and stopped eating the toads, while continuing to eat the chicken.

The crocodiles also seem to have learned to avoid newly arrived live cane toads. In areas where the toads had recently arrived prior to the training, crocodile mortality fell by 95 per cent, and in areas where they arrived after the aversion training there have since been no recorded deaths from cane toad poisoning. The team repeated the baiting programme in 2022 and found the crocodiles were still averse to eating the baited toads. “It has been kind of surprising how well this has worked,” says Ward-Fear.

The Australian government has announced it will invest nearly A$1 billion into the development of quantum computers, staking a claim in a race currently dominated by the US and China.

PsiQuantum, which is headquartered in the US but was co-founded by a team including two Australian researchers, will get A$470 million from both Australia’s federal government and the state government of Queensland, totalling A$940m ($613m). In return, the company will build and operate successive generations of its quantum computers in Brisbane, Australia.

at the University of Sydney says the announcement amounts to Australia staking a claim to sovereign capability in quantum computing and building up a quantum technology ecosystem.

“What gets me really excited about this is that the scale of investment means we are serious,” says Bartlett. While big technology companies like IBM, Google and Microsoft have made multi-billion dollar investments in quantum computing, Australia’s funding makes PsiQuantum one of the biggest dedicated quantum computing companies in the world.

Quantum computers offer the potential to complete some tasks much faster than any ordinary computer. To date, such capabilities have only been demonstrated on problems with no practical applications, but as research teams in the US, China and elsewhere race to build larger and less error-prone machines, the hope is they will start proving useful.

While many teams are building quantum computers based on superconductors, PsiQuantum’s approach involves particles of light called photons, a method which had been seen as difficult to scale up. But ahead of the Australian announcement, PsiQuantum detailing how it has been able to use a standard semiconductor fabrication set-up, of the type used to make ordinary computer chips, to build the photonic chips it needs for quantum machines.

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Australia has exported a generation of quantum researchers, including PsiQuantum co-founders . The government investment may entice such scientists to begin returning and building careers in Australia, says Bartlett. “Australia is saying we are going to sit at the big table when it comes to quantum computing.”