The Salween River, Asia’s longest free-flowing waterway that briefly serves as a border between Thailand and Myanmar, is facing a crisis as recent testing has found arsenic levels far exceeding the safe limit set by the World Health Organization. Researchers from Thailand’s Chiang Mai University first raised the alarm in September 2025 after detecting high levels of toxic contaminants in nearby rivers. Experts suspect unregulated mining in Myanmar is to blame, reports Mongabay’s Gerry Flynn.

Satellite imagery analyzed by the Stimson Center, a U.S.-based think tank, identified 127 suspected mines that opened within the Salween River Basin between 2016 and 2026. What’s being mined is unclear, but some operations likely include rare earth mines, experts say. Chemicals like cyanide, mercury, arsenic and cadmium can be released into ecosystems during rare earth mining.

The WHO’s safe threshold for arsenic exposure is 0.01 milligrams per liter. Tests of multiple water samples from the Salween River Basin have found arsenic levels several times that limit.

For the millions of people living along the Salween’s 3,300-kilometer (2,050-mile) path, the river is a vital source of drinking water, irrigation and food. Pongpipat Meebenjamart, chair of the in Thailand’s Mae Hong Son province, reported that local fishers are afraid and struggling as buyers avoid potentially toxic catches.

“It’s very urgent that, even if the contamination doesn’t exceed the safety levels, the government takes swift action to identify the source of the contamination, safe water supplies for affected communities,” Pongpipat said. “We can’t solve everything downstream here in Thailand. Here, few feel confident. Nobody in Mae Sam Laep has returned to fishing. Everyone is still afraid.”

News of the contamination has forced farmers like Di Padee to make difficult choices.

“Not many feel it’s safe to plant new crops,” he said. “For those who farm on the banks of the Salween, though, there’s really no choice but to use the contaminated water.”

Pianporn Deetes, environmentalist and executive director of Rivers and Rights, described the water pollution as a form of “invisible violence” driven by global supply chains. She warned that the Salween, once considered a pristine system, is being sacrificed for mineral extraction.

“I foresee that the global demand of the critical minerals will increase tremendously, while the sources are limited to places like Myanmar, but we need to identify no-go zones,” Pianporn said. “Clearly this is the headwater of a river system that is a vital source of life for millions of people and also significant for the ocean. How can we allow this to happen?”

A spokesperson for Thailand’s Pollution Control Department said they’re working with other agencies to provide health guidelines and secure alternative water sources, but critics say the government’s response is slow and its messaging unclear.

Read the full story by Gerry Flynn here.

Banner image: A drone shot of a mining site in Myanmar. Image courtesy of Ecological Alert and Recovery–Thailand.

Founder’s Briefs: An occasional series where Mongabay founder Rhett Ayers Butler shares analysis, perspectives and story summaries.

In a lowland forest in southeastern Madagascar, what was missing proved as telling as what was found. Researchers working in the Manombo Special Reserve trapped tufted-tailed rats in intact interior forest. But in the nearby degraded littoral areas, their traps never caught the endemic rodents. Instead, black rats, an introduced species, dominated those traps.

The finding appears in a recent genetic study of two rodents found only in Madagascar: Webb’s tufted-tailed rat (Eliurus webbi) and the lesser tufted-tailed rat (Eliurus minor).

The paper’s primary contribution is technical: it presents the first complete mitochondrial genomes for members of the Nesomyinae rodent subfamily unique to Madagascar. Earlier work relied on shorter gene fragments, which limited the resolution of evolutionary relationships. Whole mitochondrial sequences provide a clearer basis for distinguishing closely related species and identifying variation within them.

This matters because the taxonomy of Eliurus remains unsettled. More than a dozen species have been described, and additional diversity is likely. Without reliable genetic baselines, it is difficult to determine how many species exist, where they occur, or whether their populations are changing. The new sequences do not resolve these questions, but they offer a clearer starting point.

The ecological observation underscores why that kind of detail matters. Native rodents appear confined to intact forest, while disturbed areas favor generalists like the black rat. The mechanism is unclear: habitat degradation may exclude native species directly, or invasive competitors may displace them. Each possibility carries different implications for conservation and management.

There are also consequences beyond biodiversity. Rodents are hosts for a range of pathogens, and the composition of a rodent community shapes the types of diseases present and how they spread. Generalist species that thrive near human settlements often carry more transmissible pathogens. When they replace native species, the pattern of disease risk can shift, sometimes increasing exposure.

Improved genetic tools make it possible to monitor these changes more precisely, including through noninvasive sampling of environmental DNA. This makes it easier to connect ecological monitoring with public health, often framed under “One Health.”

The conclusion is modest. In Manombo, intact forest supports native species; degraded forest does not. That contrast reflects a broader pattern. Understanding it depends on careful identification, repeated observation, and the accumulation of baseline data — work that is incremental, but foundational.

Read the full story by Rhett Ayers Butler here.

Banner image: Eliurus tufted-tailed rat. Image courtesy of Elise Paietta.

Calving season for the critically endangered North Atlantic right whale has come to a close with 23 new baby whales, the most calves born in a single year since 2009.

Part of the baby boom during the winter calving season can be attributed to females giving birth at closer intervals than in years past: 18 of this year’s moms gave birth within the last six years.

“While a healthy right whale can give birth every three to four years, we had been seeing nearly 10 years between calves for some females,” Amy Warren, scientific program officer with the New England Aquarium’s Anderson Cabot Center, said in a statement.

One explanation for the calving delay is the stress of climate change, researchers say. Small crustaceans called copepods, the main food source for baleen whales, including North Atlantic right whales, have started shifting locations over the last decade, and many whales are traveling farther to find sufficient food.

There are an estimated 384 North Atlantic right whales (Eubalaena glacialis) today, living along the East Coast of North America. At least one whale was spotted near Ireland, and many are turning up in Canada’s Gulf of St. Lawrence, over a thousand kilometers from their usual habitat. Swimming to the Gulf makes their 1,600-kilometer (1,000-mile) migration from Florida to New England roughly 50% longer. That equates to more energy put into finding food, potentially leaving less resources for raising babies, Philip Hamilton, a senior research scientist with the New England Aquarium, told Mongabay in an email.

Still, the closer birth interval suggests that “those females have been more successful at foraging and are in better condition,” Hamilton told Mongabay by email. He added that this year’s high calf numbers are also partly due to a “backlog of calving females” after several years of delayed births.

An increase in births is welcome news for the species, though scientists estimate that a sustained 50 births per year are needed to restore the population. That’s a tall order for a species with just 70 reproductively active females.

Right whales were so named because they float when killed, making them the “right” whale for commercial whalers. They’re also slow going, coastal, and spend most of their time near the surface, qualities that made them easy prey for whale hunters and still put them in danger today.

Their migration takes them through busy shipping lanes and patches of ocean dense with ropes and trap lines. The U.S. National Oceanic and Atmospheric Administration estimates more than 85% of the whales have been entangled with fishing gear at least once in their lives.

So far, this year’s calves appear to be doing well. “At last count … 18 of the 23 calves had successfully migrated to the feeding grounds around Massachusetts,” Hamilton said. At this point in 2024, at least five of the 20 known calves had already died, he added.

Banner image: A North Atlantic right whale with her calf. Image by FWC Fish and Wildlife Research Institute via Flickr (CC BY-NC-ND 2.0).

THE HAGUE, Netherlands (AP) — Venezuela insisted Wednesday that a disputed mineral-rich region of Guyana was “fraudulently” taken in a 19th-century example of colonialism, arguing that a 1966 agreement and not the United Nations’ highest court should finalize ownership of the territory.

The International Court of Justice is holding a week of hearings between the South American neighbors who both lay claim to the Essequibo region, which is rich in gold, diamonds, timber and other natural resources and is located close to massive offshore oil deposits.

An 1899 decision by arbitrators from Britain, Russia and the United States drew the border along the Essequibo River largely in favor of Guyana. The U.S. represented Venezuela in part because the Venezuelan government had broken off diplomatic relations with Britain. Venezuela contends the Americans and Europeans conspired to cheat the country out of its rightfully owned land.

Venezuela has considered Essequibo as its own since the Spanish colonial period when the jungle-draped region was within its boundaries. The country argues a 1966 agreement sealed in Geneva to resolve the dispute effectively nullified the 19th-century arbitration.

“Guyana presents itself as the true, legitimate heir to British and Dutch territories, but the reality is that it is the beneficiary of colonial dispossession, formalized through fraudulent arbitration. The Geneva Agreement seeks to correct this century-old injustice,” Venezuela’s representative Samuel Reinaldo Moncada Acosta told the world court.

He said Caracas rejects the court’s jurisdiction that was “erroneously imposed” in a 2020 decision and said the 1966 agreement “establishes a framework” for a negotiated resolution.

As hearings opened Monday, Guyana’s Foreign Minister High Hilton Todd told the panel of international judges that the dispute “has been a blight on our existence as a sovereign state from the very beginning.” He said that 70% of Guyana’s territory is at stake.

The court, based in The Hague, is likely to take months to issue a final and legally binding ruling in the case.

By Mike Corder, Associated Press

Banner image: The Essequibo River flows through Kurupukari crossing in Guyana, Nov. 19, 2023. Image by Juan Pablo Arraez via Associated Press. 

Historically, conservation has mostly focused on numbers like population and habitat size. However, in the mid-2000s, scientists started to investigate animal emotions, even trauma, when considering conservation success. In a recent Mongabay podcast, Khatijah Rahmat, a geographer at the Max Planck Institute for the History of Science, shared her research examining how elephants perceive and navigate time, often differently than humans do, and what that means for conserving them.  

“If we want to understand and appreciate animals, we have to consider that they have a meaningful and complex relationship with time that is their own,” Rahmat told Mongabay podcast host Mike DiGirolamo. “Often, we think of time as a socially or culturally neutral phenomenon. We think, ‘Oh, if this is how we experience time, it is [the same] for everyone else.’ I bring up this possibility that elephants may have their own expressions of time.”

For elephants, this relationship with time appears to be deeply shaped by memory, including memories of trauma. In 2005, ecologist and psychologist Gay Bradshaw found that African elephants experienced post-traumatic stress disorder in response to witnessing violence such as family members killed by people. The animals she studied later displayed similar trauma responses seen in humans, including abnormal startle reflex, aggression, depression and even infant neglect.

Elephants have famously good memories to survive in drought-prone habitats. A herd’s oldest, and typically largest, elephant often serves as a storehouse of memory. She can remember water sources from a decades-old drought and lead her herd to them.  

“It deepens the scope of conservation in the sense that we can think of not just ensuring certain numbers of elephants but ensuring there’s habitat enough for them to exercise more intangible things like their memories of their places,” Rahmat said.

Some cultures have an understanding with elephant memory. In the Belum forest in Malaysia, Indigenous communities avoid elephant foraging routes during certain seasons. Built over millennia, this practice established a nonverbal dialogue between the two species, Rahmat added.

But when humans deforest, elephants may lose the paths they relied on to access resources and avoid people. In some areas, elephants have started to forage in the evenings rather than during the day to reduce contact with people, for example.

But these behaviors don’t mean that time and change over time are perceived by elephants the same way as humans, Rahmat said, and that’s not easily measured in a lab. In part, such research can appear subjective, which is largely a taboo for most scientists.

“Something as intangible as temporal experience can’t easily provide deeply empirical forms of evidence all the time,” she said. “It has to be observed indirectly. You need mediums. Mediums like behavior … But the effects that I’m talking about … are quite real. The phenomena I’m discussing are quite real.”

Listen to the full podcast episode here.

Banner image: Elephants in the Dzanga Bai forest clearing, Central African Republic. Image by Rhett A. Butler/Mongabay.

Researchers have for the first time assessed the extinction risk of soil-dependent animals, invertebrates and fungi. They found that some 40% of these species are either threatened or data deficient on the IUCN Red List, according to a recent study.

Soil hosts nearly 60% of life on Earth. These species are key for biogeochemical cycles, climate regulation and other ecosystem services. Yet, their risk of extinction is largely unknown, the study authors say.

To better understand how soil-dependent species are faring, the researchers first established a working definition of what species are “soil-dependent.” They found that 8,653 species on the IUCN Red List satisfy their definition: species that “spend a key part of their life cycle within a soil profile or predominantly inhabit the soil-litter interface.” The list includes terrestrial vertebrates, invertebrates like arthropods and mollusks, and fungi. However, plants weren’t included in the analysis.  

Neil Cox, study co-author and manager of the IUCN and Conservation International biodiversity assessment unit, told Mongabay by email that plants were excluded because nearly all plants are soil-dependent. Including them in the analysis would turn the review into one about the extinction risk of plants, he said.

Of the species they examined, more than 20% are listed as threatened with extinction and another 20% are data deficient, meaning there isn’t enough information to determine their conservation status.

Some 35 soil-dependent species are classified as extinct. Most of them used structures like burrows for an important part of their life stages, Cox said. For instance, several species of hopping mice (Notomys spp.) in Australia, known for excavating deep, underground burrows to escape the heat and predators, have become extinct, likely due to predation by feral cats and habitat degradation.

New Zealand’s Schmarda’s worm (Tokea orthostichon) is also likely extinct because of widespread transformation of its soil habitat and invasive species, Cox said.

Several thousand soil-dependent species aren’t even listed on the IUCN Red List, meaning their extinction risk hasn’t been evaluated, the authors write.

“Overall, though, it is extremely difficult for us to know exactly how many soil-dependent species have gone Extinct — primarily because so little is known about the conservation status of the world’s fungi and invertebrates, let alone the species that only live underground in soils,” Cox said.

To fill knowledge gaps, the researchers recommend establishing an IUCN Species Survival Commission (SSC) Soil Biota Task Force to bring soil experts together.

“This is a very necessary assessment,” César Marín, a soil ecologist at the University of Santo Tomás, Chile, who wasn’t involved in the study, told Mongabay by email. He added that the proposed working group is an urgently needed initiative that should be linked with other organizations working on soil biodiversity, including the International Network on Soil Biodiversity under the U.N.’s Food and Agriculture Organization.

Banner image: The dusky hopping-mouse (Notomys fuscus) of Australia burrows extensively in sand. Several Notomys species are extinct. Image by Boyd Essex via Wikimedia Commons (CC BY 4.0).