Polyamorous little penguins living on Phillip Island, off Australia's southern coast, are having so much sex there are now more than 40,000 of them — and it is all thanks to climate change.
Key points:
- Phillip Island's little penguin colony is growing as rising sea temperatures lead to more fish
- With more energy, the animals are mating twice each season, often with different partners
- Climate scientists warn it is important to look at the full picture of events in the ecosystem
As sea surface temperatures have increased, so too has the number of fish swimming in the surrounding coastal waters.
Phillip Island Nature Parks marine scientist and Monash University associate professor Andre Chiaradia said the influx of food meant the "opportunistic" little penguins had more time, and energy, to mate.
"The birds are breeding one-and-a-half months earlier than they used to," he said.
"When they do that, they finish earlier and think, 'Oh, I can have a second go'."
But, contrary to popular belief, Dr Chiaradia said the "sexually promiscuous" penguins were more than happy to share their love around.
"When something goes wrong, when the relationship isn't working … they go and find a new partner," he said.
"Behind the scenes, they can have four to five partners in one night."
While sea surface temperatures are currently working in favour of Phillip Island's penguins, other species have not been so lucky.
Researchers predict 90 per cent of emperor penguins could be extinct by 2100 if global temperatures continue to rise at current rates.
In 2022, the British Antarctica Survey found as many as 10,000 baby emperor penguins drowned as sea ice broke up early in the season and reached record lows.
"If you go to the other places … where this ocean temperature is beyond what it is here, the penguins are not doing so well," Dr Chiaradia said.
A false sense of hope?
With warmer waters leading to an influx of fish off Australia's southern coast, researchers warned it was important to look at the big picture.
Professor Brendan Wintle, the director of the Melbourne Biodiversity Institute and lead councillor at the Biodiversity Council, said shifts in one part of an ecosystem had impacts elsewhere.
"Ecosystems are big connections, big webs of interactions between animals and plants," he said.
"If you're seeing changes in one animal or plant species, you can be absolutely sure that's going to be having an impact on hundreds of other species that we may not be studying so closely."
While a sudden increase in the population of Phillip Island's little penguins may look like a good thing superficially, Professor Wintle said it could be a sign of troubling times ahead.
"With changing climates, you get higher peaks of good times, and that can lead to crashes, [which] can lead to the extinction of species," he said.
Professor Wintle said penguins were a perfect example of a species highly susceptible to ecosystem changes.
"It's really important for species, like penguins that rely on fisheries, that we have really strong marine protected areas that protect coastal and marine ecosystems, and allow fish stocks to be as stable as possible," he said.
"We all have to play a role in trying to make sure that we can limit climate change impacts and keep the species in the game."