In 2013, things were looking bleak for a malnourished, undersized parrot who was missing half his beak and struggling to survive in the wilds of Arthur’s Pass in New Zealand’s South Island.

Then, says at the University of Canterbury, New Zealand, one of her students came across the struggling kea (Nestor notabilis). The bird had lost the upper part of its beak, probably due to trauma. Because the kea is classified as an endangered species, the student decided to bring him into captivity.

Little did anyone know that this was a decision that would change the bird’s life and thrust greatness upon him.

The carers at Willowbank Wildlife Reserve in Christchurch, New Zealand, named the bird Kati, assuming that such a small parrot must have been a female. That assumption also made sense because it was the top half of the beak that the bird lacked. The upper beak is huge in male kea, and used for digging. It looks “like it could bite your finger off”, says Nelson.

But a DNA test revealed that Kati was actually male, so the parrot was given a new name: Bruce – “the silliest name we could think of”, says Nelson.

This wasn’t the only surprise. Bruce is one of nine males and three females held at Willowbank. But in spite of his beak, he quickly asserted himself as the alpha male in the ‘circus’ – the collective name for a group of kea.

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The key to Bruce’s success was that, without the top half of his beak, he could use the bottom portion as a weapon.

Nelson says it is not just bluffing on Bruce’s part, as his lower beak is “very straight and sharp and can be used to joust the other birds”.

The other males, most of which are over a kilogram and outweigh the 800-gram Bruce, can’t respond in kind because their upper mandibles cover their lower beaks.

“So even if they tried headbutting another bird, it would just be a blunt rounded curve that would hit them,” Nelson says. “Whereas Bruce pushes himself so fast forward against another bird that he kind of topples over.”

She adds that it’s “a serious jab, and the other birds really don’t like it. I mean, when he does that, they’re just wings in the air, jumping back as fast as possible.”

Out of 162 aggressive interactions recorded between all the male birds over a total of four weeks, Bruce always came out on top, winning each of the 36 interactions in which he took part.

He also maintained absolute control and priority over the four feeding stations in the birds’ enclosure and even co-opted lower-status birds to help clean his lower beak and preen him – something none of the other captive birds did.

The team then wanted to see what kind of toll Bruce’s dominance was taking on the males fighting for their place in the hierarchy. They found that Bruce’s stress hormones levels were by far the lowest, seemingly, because his alpha status was so secure, he only had to display aggression a fraction of the times required of the other males.

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The team says, with the exception of humans, Bruce provides the first example of a severely injured animal “individually achieving and maintaining alpha male status through behavioural innovation alone”.

They also say he is living proof that a difference is not always a disadvantage, and that it proved unnecessary to repair his beak with a prosthetic.

“I really like Bruce, actually,” Nelson says. “When there is reason to fight, yeah, he’ll fight and he’ll fight hard, and scrappy. But he’s not a bully.”

Same-sex sexual behaviour may help monkeys and apes rise up the social ranks and ultimately have more offspring – and it seems to be especially beneficial in harsh environments where there are lots of predators, say, or a shortage of food.

That’s the implication of a study looking at why the level of same-sex behaviour varies in different primate species. It supports the idea that, contrary to what is commonly assumed, same-sex sexual behaviours in apes and monkeys are an adaptive trait that boosts survival.

It has often been claimed that same-sex behaviour is somehow “unnatural”. But in addition to people, it has now been reported in at least 1500 animals, from insects and dolphins to bison and bonobos.

There are many reasons to think this is the tip of the iceberg. Most species haven’t been closely studied; same-sex behaviours often aren’t recognised when seen because the sexes of the individuals involved may not be clear; and even when such behaviours are recognised they may not be reported.

Of the 20 or so mammal species that have been closely studied over long periods, same-sex behaviour has been . In a colony of rhesus macaques (Macaca mulatta) on the Puerto Rican island of Cayo Santiago that has been studied for many decades, for instance, three-quarters of males engage in same-sex behaviour, at Imperial College London and his colleagues reported in 2023.

In other words, there can now be no doubt that same-sex behaviour is entirely natural. The question is why?

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This has sometimes been referred to as “the Darwinian paradox”, because of the common assumption that homosexual behaviour is non-adaptive – that is, that it doesn’t help individuals have more offspring, or boost the survival chances of those they do have.

Various explanations have been proposed for why same-sex behaviour is so common if it is non-adaptive. One is that same-sex behaviour occurs , that is, because individuals can’t tell the difference between males and females. This is probably true of simple animals such as insects, but it’s certainly not the case for highly intelligent animals such as apes and dolphins.

Another is that it’s a side effect of selection for other traits. For instance, it has been suggested that some traits that boost reproductive success in women may be linked to a greater likelihood of homosexuality in men.

It’s also possible that same-sex behaviour is adaptive, after all. One idea is that it helps males build coalitions that ultimately give them more access to more females. “Same-sex behaviour is, if you want, a currency that you can use to navigate your way in these societies,” says Savolainen.

His team has now analysed data on the prevalence of same-sex behaviour in 59 primate species and looked for associations with environmental and social factors. Among other things, they found that it was more likely to occur in drier environments where food was scarce or where there was more predation pressure, as well as in more complex societies.

For a behaviour to become more common in stressful environments does suggest it is adaptive. If, say, same-sex behaviour was done for pleasure only, you’d expect it to be less common in stressful environments.

“Same-sex behaviour may facilitate better cooperation and cohesion by strengthening social bonds, which is particularly important in these stressful environments,” says team member , also at Imperial.

“But to demonstrate adaptive value, the behaviour needs to be linked to increased fitness, that is, a higher number of offspring,” says Savolainen. “This is precisely what I intend to test in macaques.”

So we are not yet at the point where we can conclusively say same-sex behaviour in at least some primates is adaptive, but it could be that science is about to turn yet another of our preconceptions about this behaviour on its head.

What does this tell us about homosexual behaviours in people? Well, if these findings are confirmed, it might help explain why it is as common as it is. What it does not tell us, the researchers stress, is anything about the rights or wrongs of such behaviour – this is the so-called naturalistic fallacy. That is, human behaviours should not be judged based on what animals do.

That said, there is a certain delicious irony in the idea that when it comes to the survival of the fittest, we may need to redefine who the fittest really are.

Killer whales and dolphins have been working together to hunt salmon in the northern Pacific Ocean, an unexpected finding that further reveals the complex social lives of marine mammals.

Video cameras and sensors attached to nine killer whales – also known as orcas – showed four of them diving with numerous Pacific white-sided dolphins towards Chinook salmon hiding in the depths off northern Vancouver Island. Three more whales were observed by drone. The orcas ate the salmon, while the dolphins scavenged the scraps.

“They were cooperatively foraging,” says at Dalhousie University in Canada. “You could anthropomorphise it and say that they’re being friends for hunting purposes.”

Also known as king salmon, Chinook salmon can grow more than a metre long and are often too big for dolphins to eat.

But northern Vancouver Island whales are messy eaters and often tear fish apart to share with family, leaving blood, scales and fragments for dolphins to consume. The dolphins help whales “scout” out salmon, the researchers believe.

Six out of the 12 whales interacted with the dolphins, orienting to face them a combined total of 102 times in the videos. Four dived with dolphins as deep as 60 metres, where it’s dark and salmon can take cover among rocks and crevasses.

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While both species emitted clicks and buzzes, the sensor data revealed that whales often reduced their echolocation – apparently to “eavesdrop” on the dolphins. Since echolocation is narrowly focused like a spotlight, a large number of dolphins scanning the water may improve a whale’s chances of finding fish, says Fortune.

“It’s like turning on the high beams” on a car, she says, “and the light is the sound.”

Scientists have previously found inter-species cooperation such as fish leading an octopus toward crustaceans, or honeyguide birds leading a human to bee colonies. But killer whales’ scientifically observed interactions with other species have typically been to prey on or harass them.

Orcas around the Iberian peninsula have recently rammed and sunk half a dozen sailboats, although scientists say it’s more likely than attacking them.

at Ocean Wise, a global conservation organisation, argues dolphins in the study are stealing scraps rather than cooperating with whales. In a she and her colleague published this year, drone footage in the same area showed whales appearing to ignore, play with or, in one case, lunge at dolphins. Her study concluded dolphins were mainly seeking protection from a particular population of mammal-eating orcas known as Biggs’ killer whales, which avoid the resident killer whales.

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“We observed no clear evidence of benefits to the killer whales,” says Visona-Kelly.

last month reported 30 to 40 Pacific white-sided dolphins circling an emaciated killer whale known to researchers as I76, who dived and didn’t re-emerge. This suggested the dolphins may have “exhausted I76 so that he was unable to return to the surface”, according to the paper.

at the University of St Andrews, UK, says the new research convincingly shows cooperation, regardless of whether the whales could interpret dolphin echolocation or were simply attracted to the commotion as a possible sign of fish.

“These animals are smart and behaviourally flexible,” he says. “We’ll see all kinds of interactions between killer whales and dolphins, everything from the killer whales eating them to playing with them to cooperating with them.”