A species of amoeba discovered in California鈥檚 Lassen Volcanic National Park can survive and thrive in temperatures that had been considered impossibly high for complex life.

Nicknamed the fire amoeba by the researchers who collected it, Incendiamoeba cascadensis can survive in waters heated up to 70掳C. However, it only retains the ability to eat and reproduce up to temperatures of 63掳C, and it loses the ability to move around above 64掳C.

Previously, according to at Syracuse University, New York, 60掳C was considered the 鈥�4-minute mile鈥� barrier for eukaryotes, the branch of the tree of life that contains all complex life forms including animals and plants, and that is defined by the presence of cells in which DNA is protected within a nucleus.

The discovery shows that eukaryotes can grow at temperatures higher than once thought possible, Oliverio says, and now that the fire amoeba has been found, more similarly tolerant extremophile species will likely be uncovered elsewhere.

鈥淭he 4-minute mile was long thought to be impossible,鈥� says Oliverio. 鈥淏ut once accomplished, it only took weeks to be broken again.鈥�

Simpler organisms can survive at even more extreme temperatures. Methanopyrus kandleri, a single-celled archaeon that lacks a nucleus, can .

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Oliverio and her colleagues collected I. cascadensis from a small geothermal stream within California鈥檚 Lassen Volcanic National Park, flowing through a 鈥渂eautiful meadow鈥� less than half a metre wide for most of its length. Temperatures in the stream range from 49掳C to 65掳C, with a pH range of 6 to 7.

At full stretch, I. cascadensis is, on average, about 40 micrometres long and 10 碌m wide, says Oliverio.

鈥淭his is over 10 times the size of the average bacterial cell, and closer to the width of a human white blood cell,鈥� she says. In such a hot environment, the fire amoeba is the top-order predator, feeding on thermophile bacteria, which are far more common.

鈥淚t is somewhat analogous to going into a forest where you will likely see lots of plants but very few bears, even though they are common and live in these environments, too,鈥� says Oliverio.

at Monash University, Australia, says the discovery means he will have to rewrite his lectures on extremophiles.

鈥淚t鈥檚 a very exciting finding that extends the temperature record for the growth of eukaryotic life by at least 3掳C 鈥� a significant leap,鈥� he says.

The team cultured the amoeba back in the lab, where they tested the upper and lower limits of its survival by studying it at 17 different temperatures, ranging from 30掳C to 64掳C.

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A salt-loving microorganism found in places like the Dead Sea can not just survive but actively grow in conditions close to those that may be found just under the Martian surface

They found there was no growth below 40掳C or above 63掳C, with the optimal range between 55 and 57掳C. Above 64掳C, the amoeba rolls up into a cyst to protect itself from the heat. After exposure to temperatures above 70掳C, these cysts are 鈥渋nactivated鈥�.

Intriguingly, when the team searched worldwide e-DNA databases for a signature similar to I. cascadensis, they discovered some RNA matches from a geothermal mat in the Taup艒 Volcanic Zone in New Zealand, and three matches from Yellowstone National Park in the US.

Some of these may be distinct, closely related species to the fire amoeba that haven鈥檛 yet been collected or cultured. The search should continue for even more extreme life forms, says Oliverio.

鈥淎s far as we know, there is no reason why 63掳C is the hard limit.鈥�

The world鈥檚 most famous dinosaur, Tyrannosaurus rex, was probably warm-blooded like birds and mammals, new evidence, obtained from 66-million-year-old tooth enamel, suggests, adding weight to previous findings.

at South Carolina State Museum, who wasn鈥檛 involved in the new study, says the research means 鈥渢he opening to the last Jurassic World flick was one big pile of Hollywood bunk鈥�.

鈥淭hat film premised that dinosaurs could not survive in the modern world, except near the equator,鈥� says Persons. 鈥淣ot so. The evidence indicates that a Tyrannosaurus would be comfortable in subtropical and even mild climates.鈥�

at the University of California, Los Angeles, and his colleagues analysed the chemistry in the enamel of three T. rex teeth and compared them with five similarly aged fossilised crocodile teeth.

The researchers also compared their results with data from mammals such as elephants and mammoths to try to determine whether T. rex was also an endotherm 鈥� an animal that can regulate its body heat through its metabolism. Ectothermic, or so-called cold-blooded animals like crocodiles, often warm up by basking in the sun instead.

Endothermy is common in large animals and even some fish, says Eagle, allowing them to move around and exhibit more sustained activity to find food and migrate, and to live in colder environments. It has long been thought that many dinosaurs, including T. rex, were also warm-blooded.

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鈥淚t comes at a cost though 鈥� higher metabolic rates mean higher food requirements and potentially more active hunting to acquire it,鈥� he says.

Within the enamel chemistry, the researchers focused on the abundance of bonds between rare heavy isotopes of carbon and oxygen, known as carbon-13-oxygen-18 bonds. These bonds are more abundant in minerals that form at cold temperatures than minerals that form at warm temperatures.

鈥淭herefore, in a very old tooth we can measure carbon-13-oxygen-18 bond abundance and figure out whether it formed in a hot or cold body.鈥�

He says T. rex had a body temperature of around 36掳C, similar to large modern mammals but below many modern birds.

鈥淲e also found that the reconstructed temperature of T. rex was significantly elevated compared to temperatures derived from crocodile teeth from the same geological formation 鈥� Hell Creek in Montana,鈥� Eagle says.

The researchers also say that T. rex body temperatures were higher than the ambient temperatures in prehistoric Montana, reconstructed both from isotopic estimates and climate models.

鈥淯sing thermal performance curves and climate modelling based on these results, we found that the entire North American continent would have been habitable for T. rex in the Cretaceous Period,鈥� he says.

The shocking fossils that show T. rex wasn鈥檛 the king of the dinosaurs

We've always thought that Tyrannosaurus rex was an unchallenged apex predator during the dying days of the dinosaurs. But a fresh look at controversial fossils has prompted palaeontology鈥檚 biggest-ever U-turn

Persons says there was already extensive evidence that T. rex was warm-blooded, including bone growth rates and predator-prey ratios 鈥� with energy-hungry endotherms than ectotherms 鈥� and a 鈥渟lew of anatomical traits consistent with high-performance athleticism鈥�.

at Carthage College in Wisconsin says the new work is an 鈥渆xample of science in action, converging upon a single, robust hypothesis, which in this case reveals T. rex as an active top predator鈥�.

The researchers 鈥渕ake the case for a wide geographic distribution for T. rex, showing that it could tolerate cool temperatures in the north of its range and tolerate the tropical temperatures in the south鈥�, says Carr. 鈥淎nd in both cases, T. rex鈥榮 body temperature is higher than the average air temperature. That result is consistent with the hypothesis that T. rex might have migrated from Asia into North America at high latitudes.鈥�

A humpback whale has been observed for the first time shortly after birthing a stillborn calf, showing apparent signs of grief similar to those seen in other large mammals such as elephants.

The encounter began at around 8am on 17 July 2025, when Andrew Mulville at the Sea World Foundation, an Australian charity, was aboard a boat a kilometre offshore from the Gold Coast in Queensland.

He noticed two adult whales milling in the same location, occasionally diving, vocalising and rolling on the surface. By 8.30am, Mulville saw and recorded an amniotic membrane floating on the surface, indicating a birth had occurred but, concerningly, no blood or placenta was visible.

He then placed a camera underwater and saw a stillborn calf, less than 4 metres long, that had sunk to the sandy seabed. The mother repeatedly approached the calf, looked at it eye to eye, and touched it with her head and pectoral fin.

While such behaviour has been recorded in toothed whales with dead calves, it is extremely rare in baleen whales such as humpbacks (Megaptera novaeangliae).

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With a live newborn, humpback mothers typically try to push the calf to the surface to help it breathe, but in this case she didn鈥檛, perhaps suggesting she knew it wasn鈥檛 alive.

Meanwhile, the second adult stayed nearby, apparently supporting both the mother and dead calf.

Although stillbirth in mammals is common, it is extremely rare to observe the event in whales, says at Griffith University in Australia, who co-wrote a paper with Mulville on the observation. To his knowledge, it has never before been witnessed in humpback whales.

鈥淚t鈥檚 really important to not humanise an encounter like this,鈥� says Meynecke. 鈥淏ut then also to understand that it鈥檚 a mammal, and we have evidence of, not necessarily grief, but the really dramatic change of behaviour that we see in other mammals such as elephants when they lose a member of their group or when they lose their calves.鈥�

Mulville observed the whales for the next 2 hours, as they stayed in the immediate vicinity of the dead calf and continuously dived down to it. On the next two days, members of the public on shore reported seeing the two adult whales in the same location.

The incident has raised concerns about why the calf was stillborn, especially because seven deceased humpback whale neonates and one deceased young whale of unconfirmed age were also observed in July 2025 in the same region. None of these appeared to be the stillborn whale observed by the scientists.

Also, while it has become increasingly common for humpbacks to calve in southern Queensland as their population has grown, no one is sure why so many female whales are now giving birth hundreds of kilometres south of their traditional breeding grounds in the Great Barrier Reef.

It was also extremely unusual that the mother didn鈥檛 deliver her placenta, and this may have also placed her at risk, says Meynecke.

Photos of her distinctive fluke have been uploaded to a database of 16,000 individuals, so the researchers hope she will be recognised if she re-appears in coming seasons.

at the University of Queensland says descriptive case study reports such as this one 鈥渞un the risk of anthropomorphising observed behaviours鈥�.

鈥淗owever, the study does present a balanced argument of how the observed behaviour could be interpreted and notes that the terms 鈥榞rief鈥�, 鈥榚motion鈥� and 鈥榙istress鈥� must be used with caution since we cannot definitively assign these terms to the observed behaviour,鈥� says Dunlop.

She says only with 鈥渕ore data and more occurrences鈥� would it be possible to test the hypothesis that what was observed was emotional or grieving behaviour. 聽

Floating Futures
Alessandro Gandolfi

Imagine a city where suburbs float on water. Floating homes already exist in coastal communities in places like the Philippines and Vietnam. Now, high-income nations facing dangerous sea-level rise are looking to those examples.

Among them is the Netherlands, where over a quarter of the land is below sea level and around two-thirds of it is at risk of flooding.

This photograph shows floating houses in the IJburg district at the edge of Amsterdam, the largest Dutch city. The image comes from , a new series by photojournalist Alessandro Gandolfi.

The affluent, relatively high-density IJburg community comprises 158 waterside homes, 55 of which are floating. Residents are connected by bridges and roads, and most houses have a boat outside instead of a car.

Simply raising the dykes is no longer enough against the rising waters, Gandolfi writes in his photo essay. 鈥淓xperts warn that mastering water鈥檚 whims is an illusion. The answer, they say, lies in a shift of mindset 鈥� the philosophy of meebewegen: not fighting against water, but learning to live with it.鈥�

The homes at IJburg aren鈥檛 houseboats or retrofitted vessels like the ones lining Amsterdam鈥檚 canals, but architect-designed homes intended to encourage community living. They are built to be sustainable, with rooftop solar panels and careful management of sewage and other waste.

But their biggest difference from other houses will always lie below, in their watery foundations.

Within just a 17-kilometre radius in one Indonesian archipelago, there is an explosion almost every hour as locals practise 鈥渂omb fishing鈥�, destroying coral reefs and decimating marine life.

Over 483 days between May 2023 and September 2024, at University College London and his colleagues deployed an acoustic monitoring system at Spermonde Archipelago, south-west of Sulawesi, Indonesia.

As well as being a global coral reef biodiversity hotspot, it is a location where fishers detonate explosives underwater, stunning and killing fish that can then be easily harvested.

鈥淭he sound of bomb fishing is so loud that if you鈥檙e on a dive it can shake you out of your skin,鈥� says Williams. 鈥淵ou feel it more than you hear it. But if you put your head up on the surface, you likely won鈥檛 even see the boat responsible because the sound of bomb fishing travels such a huge distance underwater.鈥�

The recording equipment sat at a depth of 17 metres and was able to detect explosions inside a radius of almost 17 kilometres. The team used AI to analyse their 3650 hours of raw audio. They recorded 3567 explosions, or just over 23 per day while the device was underwater.

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鈥淲e have shown the true extent of this practice in a known hotspot for the first time ever, which we hope will drive action to curb this destruction,鈥� says Williams.

One of the biggest issues is that there is an illegal supply chain underpinning the bomb fishing, usually involving the sourcing of fertilisers and fuses or detonators, he says. 鈥淚n other regions these may be stolen mining explosives or even military explosives.鈥�

Once the fishers have the explosives, enforcement at sea is sparse. 鈥淚t鈥檚 like Whac-A-Mole targeting the bomb fishers. The best approaches should tackle the illegal supply chain that gets the materials needed to make explosives to bomb fishers or sellers of these,鈥� says Williams.

Bomb fishing is a problem across the tropics, and part of the solution is retraining locals in sustainable tourism and reef restoration, he says. 鈥淚t鈥檚 been documented in 34 countries, from South America to the Mediterranean to the East Coast of Africa and South-East Asia.鈥�

, who wasn鈥檛 part of the work, is currently studying at the University of Queensland, Australia, and has worked extensively with Indonesian non-governmental organisations in reefs targeted by bomb fishing. He says he wasn鈥檛 surprised at the scale of the聽problem.

鈥淚 expected the frequency to be high, but studies regarding bomb fishing are relatively scarce because it is notoriously difficult to quantify,鈥� Gotama says.

He says the new method employed by the researchers might help combat the practice. 鈥淚f this acoustic method could be replicated elsewhere, it could help with detecting and quantifying blast fishing and help identify hotspots of activity,鈥� says Gotama.

鈥淭hat could be valuable not only for ecological monitoring, but also for targeting enforcement and evaluating whether management interventions are actually reducing blast fishing.鈥�