Scientists studying marine mammals off the Pacific coast of North America have observed an unusual interaction between two highly intelligent predators: killer whales and dolphins apparently hunting together.

The observations were recorded in British Columbia waters, where researchers documented groups of fish-eating resident orcas moving alongside Pacific white-sided dolphins during salmon hunts.

“We thought that there was a general east-west split in their populations based on quite old genetic techniques that wouldn’t be used nowadays,” said lead author and marine biologist at the University of Exeter, Daniel Moore, to Discover Wildlife. “We started the study wanting to understand that east-west split a bit more, but using modern techniques, and what we found was just not expected at all.” 

In the sheltered waters of Mexico’s upper Gulf of California, a remarkable sighting stirred conservationists: a small pod of vaquitas, the world’s most endangered marine mammal, was observed together, suggesting that hope for recovery may yet exist. The species, long believed to number in the single digits, appears to have shown signs of resilience—albeit fragile—and the sighting has renewed calls for rigorous protection and enforcement.

Developed in partnership with the SETI Institute and marine biologists, the project aims to build the first systematic tool for analysing dolphin communication using a Large Language Model (LLM) architecture, similar to that used in human text-based AI systems.

Wikie and Keijo represent the tragic fate of marine mammals held in parks for human entertainment. Their lives in captivity were limited and isolated, far from the expansive oceans they once could have roamed freely with their families. Known for their complex social structures and strong family bonds, orcas are highly intelligent creatures that typically live in pods, passing down knowledge and forming deep, lifelong connections. But for these orcas, their natural behaviours were denied, replaced by confined pools, restricted social interactions and repetitive performance routines.

Dolphin intelligence is evident in a variety of ways. They demonstrate problem-solving abilities, self-awareness and complex social interactions. Studies have shown that dolphins can recognise themselves in mirrors, which so far has only been achieved by the most intelligent of animals. Furthermore, they can understand symbolic language and have been observed using tools. For example, they use marine sponges to protect their rostrums while foraging on the ocean floor.

The study found that dolphins displayed the open-mouthed gesture more frequently during interactions with others than when playing alone. Even more interestingly, they tended to use this gesture when their playmate could see them, suggesting that dolphins are aware of their friends’ attention and adjust their behaviour accordingly.

Established in November, this initiative marks a concerted effort to protect some of the most vulnerable dolphin species inhabiting the world’s rivers, many of which are on the brink of extinction.

The Global Declaration for River Dolphins was signed by nine countries, including Brazil, Colombia, and India, all home to river systems where these endangered species are found. This agreement is pivotal as it represents the first international commitment explicitly focusing on the conservation of river dolphins, which face habitat degradation, pollution, and fishing threats.

Originally developed for use in pesticides, paints and fire-resistant materials, POPs are highly toxic and do not easily break down in nature. These chemicals have leached into the soil, air and waterways, eventually reaching the ocean. They are absorbed by plankton at the bottom of the food chain and increase in concentration through a process known as biomagnification. As a result, marine mammals, which are at the top of the food chain, accumulate high levels of these toxins.

In a joint study, scientists found alarming concentrations of PFAS chemicals in Victoria’s critically endangered Burrunan dolphins. 

These chemicals, widely used in food packaging, firefighting foam and non-stick cookware, are sometimes called “forever chemicals” as they almost never break down in the environment.