From the frozen islands of the Arctic to the deepest trenches of the Pacific, 2025 has delivered a whole host of amazing wildlife discoveries, adding to our ever-growing understanding of the natural world.
This year, satellites revealed a never-seen-before haul-out of gigantic walruses on Svalbard, while drones uncovered the largest nesting site of endangered giant South American river turtles ever recorded in the Amazon.
Meanwhile, deep-sea robots stumbled upon thriving – and entirely new – ecosystems, ancient mud volcanoes and astonishing life hidden beneath calving Antarctic ice.
Greatest wildlife discoveries of 2025
Satellites spot new walrus haul-out in Svalbard
Scientists discovered a new walrus haul-out on a stretch of shoreline in Svalbard – a remote archipelago in the Arctic Ocean, found between mainland Norway and the North Pole.
The enormous marine mammals, which can weigh almost two tonnes, were spotted using satellite imagery as part of Walrus from Space, a conservation project organised by the World Wide Fund for Nature (WWF) and the British Antarctic Survey (BAS).
"Since 2021, WWF and BAS have been asking the public to become ‘Walrus Detectives’ and help contribute to conservation science by searching for and counting walruses in thousands of satellite images taken from space," said WWF on its website.
Rats played a pivotal role in the deforestation of Easter Island
The story of Easter Island needs a rewrite. According to a study published this year in the Journal of Archaeological Science, humans weren’t solely to blame for the disappearance of trees on the remote Pacific island. Rats played a pivotal role too.
The study’s authors, Carl Lipo and Terry Hunt, suggest that before human settlers arrived, Easter Island was dominated by a unique species of large palm, which could live for up to 500 years, but took 70 years to mature. Then around 1200 CE, the Polynesians arrived with various non-native species, including sweet potatoes, which they farmed, and Polynesian rats, which they ate.
The rats, however, cut loose and made themselves at home in the canopy, where they feasted on the palm trees’ fruit. "Palm nuts are rat candy,” said Lipo. "The rats went bananas.” With no native predators to control their numbers, the Polynesian rat population boomed. Within 50 years, there were 11 million rats and an estimated 95% of the palms’ seeds had been eaten.
The slow-growing palm tree didn’t stand a chance. To compound the problem further, Polynesian settlers cut down palm trees to establish their sweet potato fields and burned patches of forest to make ash for fertiliser. The palms struggled to regenerate, and over the next 450 years, 20 million trees were lost.
Remember the Chicago Rat Hole? Turns out it wasn't a rat after all...
On 6 January 2024, Chicago comedian Winslow Dumaine photographed the near-perfect impression of what looked like a brown rat on a sidewalk in Roscoe Village, a neighbourhood in the north of the US city.
The so-called 'Chicago Rat Hole' – a cartoon-like splat complete with tail and claws – had been known to residents for years, but when Dumaine posted the image on social media, it suddenly shot to fame. People flocked to the area from miles around just to get a glimpse of the mysterious hollow.
But despite the hole's rat-inspired name, some locals questioned the creature responsible for it. Earlier this year, a new study published in Biology Letters revealed that the culprit was in fact not a rat, but more "likely a squirrel".
RNA extracted from a woolly mammoth for the first time
A team of researchers from Stockholm University and the Swedish Museum of Natural History successfully isolated and sequenced RNA molecules from a juvenile woolly mammoth that lived in the frozen wilderness of Siberia roughly 40,000 years ago.
Published in the journal Cell, the study offers proof that RNA, like DNA and proteins, can be preserved for long periods of time.
Analysis of the RNA supports suggestions the Ice Age animal was attacked by cave lions shortly before his death.
- Woolly mammoth vs elephant: What's the difference?
- Should we bring mammoths back?
- Soft tissue of 40,000-year-old Siberian mammoth offers astonishing glimpse into final moments of its life
Pacific sleeper sharks filmed for the first time in the South China Sea
Pacific sleeper sharks were caught on camera for the first time in the South China Sea, giving researchers vital new clues about the behaviour and distribution of these elusive deep-sea giants.
The extraordinary footage was recorded during a study exploring how large animals feed in deep-sea environments. To investigate the subject, researchers lowered a cow carcass to a depth of 1,629 metres, southeast of Hainan island. They placed a camera at the site and waited. It was then that they filmed the Pacific sleeper shark.
New type of lion roar discovered
A new study has confirmed that African lions produce two distinct roar types instead of one (as was previously thought) – these include the well-known full-throated roar and what researchers are calling an 'intermediary roar'.
- Why can only big cats roar?
- It is one of the most iconic, revered – and feared -mammals in the world – with a powerful roar that can be heard for miles
Using machine learning, the researchers created an automated system that classifies calls with a 95.4% accuracy. The team believes the technique offers a simpler and more reliable alternative to traditional monitoring tools such as camera traps or spoor (track and scent) surveys.
The discovery could transform how conservationists monitor and protect threatened populations across Africa.
Scientists capture first-ever footage of killer whales making seaweed grooming 'tools’
Killer whales were filmed making and then using what is thought to be the cetacean equivalent of a pumice stone.
Reported in Current Biology, this is the first time that a marine mammal has been seen creating a grooming-related tool and then using it with another individual.
- 11 animals that use tools in surprising and clever ways – including a few you may not expect
- “No other predator is able to challenge them” – this deadly, intelligent ocean killer works in a team to stun, submerge and launch at its prey
Lots of animals, including primates, birds and elephants are known to use tools, but examples among marine mammals are more limited. Some bottlenose dolphins wear sponges on their beaks, seemingly to help them catch fish, whilst humpback whales make 'bubble nets’ to help them catch krill. In both cases, however, the behaviour is restricted to foraging contexts, and the animals don’t modify physical objects.
Drones document world’s largest known nesting site of giant South American river turtles
A new study has identified the world’s largest known nesting site of endangered giant South American river turtles.
With the help of drones, scientists recorded more than 41,000 of the large reptiles on the Guaporé River along the Brazil-Bolivia border.
- Arribadas: why turtles nest en-masse
- Drones spend 12 days flying over mega nest of huge animals in Amazon. Scientists say it's the largest ever found
Ancient mud volcano found Arctic Ocean - and it was covered with life
With the help of a remotely operated vehicle, researchers discovered a 7,000-year-old underwater mud volcano in the Arctic Ocean.
Found 400m deep in the Barents Sea, experts think the submerge mount is a sanctuary for vulnerable Arctic species.
"Today we have discovered something exceptional,” said Professor Giuliana Panieri from The Arctic University of Tromso (UiT) in Ocean Census’ video sharing the discovery of the Borealis Mud Volcano.
"One would think that a volcano was not the most hospitable place for living organisms,” says Panieri. But using REV Ocean’s remotely operated vehicle, they could observe the volcano closely and learned that the crusts around its crater provide numerous animals with habitat, shelter and food.
Hidden world discovered beneath ice in Antarctica
A team of international scientists aboard the Schmidt Ocean Institute’s research vessel, R/V Falkor (too) shared a remarkable set of images and videos from a section of Antarctic seafloor that had been concealed beneath ice for centuries.
The shots were taken on a mission to explore the freshly exposed seabed left behind by the enormous A-84 iceberg, which dramatically broke away from the George VI Ice Shelf on 13 January 2025.
- Scientists just spent 16 months exploring Earth's oceans – here's what they found
- When a colossal iceberg broke free from Antarctica, scientists found something staggering beneath it
Deep-sea robot records never-seen-before hydrothermal activity in Papua New Guinea
Researchers exploring the waters off the coast of Papua New Guinea were amazed to find a type of hydrothermal field that has never been seen before.
The scientists had an inkling there might be some hydrothermal activity in this region but, despite several research trips in the same area, they only spotted the field when they sent an underwater robot – the ROV Kiel 6000 – down to 1,300 metres on a seamount near the island of Lihir.
The ecosystem was full of life. There were mussels, tube worms, shrimp and sea cucumbers all over the rocks. “In places, you couldn't see a single patch of rock because everything is so densely populated,” said marine geologist Dr. Philipp Brandl, who wants to return to the site again to study these species in more detail. He suspects some of them are new to science.
- When scientists sunk a deep-sea robot 1,300 metres into the Pacific Ocean they found something staggering...
- Deep-sea submersible films thousands of bizarre red animals 1,500m deep off coast of Argentina
- Peculiar deep-sea creature with huge eyes discovered 3,628m down off Californian coast
Top image: Orca. Credit: Getty
