Some killers work alone. Others hunt in packs. In a few cases, though, a member of one species combines forces with a member of another. And the result can be devastating to their prey. Here’s our pick of the most gruesome twosomes…
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Deadliest duos on the planet
Pact animals
The relationship between coyotes and American badgers can be tense. Both species are partial to burrowing rodents such as ground squirrels and prairie dogs, which puts them in direct competition that can turn to violence. Sometimes, though, they suspend hostilities and hunt together - very successfully as it happens.
It makes perfect sense to join forces. Badgers stalk their prey underground, while coyotes chase them down on the surface. To escape a badger, a rodent must flee its burrow, and faced with a coyote, it must go to ground. Against a badger-coyote tag-team, though, there’s nowhere to hide. Studies show that both badgers and coyote are both more successful when hunting as a team.
Little and Large
Dewdrop spiders spend their lives treading very carefully. These tiny arachnids specialise in pilfering prey from the webs of larger spiders - the largest of all web-building spiders, no less.
With a leg-span as big as an adult human’s hand, a giant golden orb-weaver is hundreds of times the weight of its light-fingered guest and could easily make short work of it, given the opportunity and inclination. And yet it doesn’t. That is partly due to the dewdrop’s ability to avoid detection and the fact that it’s too small to be a tempting meal for its host. But it might also be because it is worth more to the orb-weaver alive than dead.
Because there’s good evidence that it is an accomplice rather than a parasite. Research shows that orb webs containing dewdrop spiders snare more prey than those without. One theory goes that the little spiders’ silvery markings attract insects to the web like moths to a flame. Whatever the precise mechanism, the dewdrop ensures its host doesn’t go hungry, and it gets to eat the leftovers in return.
Feathered friends
When dwarf mongooses emerge from their den in a termite mound after a night’s sleep, their partners in crime are usually already waiting for them and will even issue a wake-up call through the entrance-hole if they sleep in longer than usual.
These busy little mammals rarely go anywhere without a hornbill. They spend their days rooting around for invertebrates and small reptiles and rodents, and the hornbills pick off prey flushed by the mongooses’ rummaging.
In return, the beady-eyed birds keep a lookout for danger and will utter an alarm call when they spot raptors approaching. The birds even sound the alarm for raptor species that pose a threat to the mongooses but not to themselves.
Thick and thin
On the reefs of the Indo-Pacific, leopard coral groupers and giant moray eels have struck up a working relationship that improves the hunting success of both parties.
It starts with a grouper approaching a moray and signalling its intentions with a characteristic shake of the head. This prompts the eel to leave its burrow and join the grouper on an expedition over the reef.
When the grouper spots something edible lurking amongst the coral, it adopts a head-down posture that communicates its position to the eel, which can wriggle into nooks and crannies inaccessible to the chunkier grouper. The eel may catch the morsel for itself, but sometimes it will succeed only in flushing it into open water, where the grouper waits ready to pounce.
A grouper will nurture relationships only with the most competent eels. It’s a level of collaborative sophistication that puts them on a par with chimpanzees.
Sweet stuff
A story goes that the honeyguide, a little African bird that lacks the strength to break into a bees’ nest to feed on the grubs and beeswax it desires within, enlists the help of a ratel, a sturdy badger-like mammal with a fondness for honey, by calling it and leading it through the forest to the bounty. The ratel tears open the nest and the two of them feast on the contents.
The story may be only half true. The ratel’s role has not been reliably documented and, if it happens at all, it is likely to be very rare. However, honeyguides do routinely cooperate with another sturdy mammal with a fondness for honey.
People in many African countries have learned to work with honeyguides to locate wild bees’ nests. In northern Tanzania, an estimated 8–10 per cent of the total diet of the Hadza people is collected with the help of honeyguides.
Tough love
Alliances between different species of predator are not always entirely frictionless affairs. The day octopus can often be found foraging with a variety of fish species, such as groupers, wrasses and goatfish. Working together they can flush and catch more prey than they would do if hunting alone.
However, these relationships only work if both parties put in as much as they take out. Research shows that the octopus will sometimes discipline a fish that seems to be getting more than its fair share by punching it with one of its tentacles.
Coalition forces
It’s hard to imagine that orca need any help catching prey. And yet research published in December 2025 shows that they team up with Pacific white-sided dolphins to hunt salmon.
By working together, the predators are able to herd the fish more effectively and, by eavesdropping on each other’s acoustic clicks, they can build a better picture of the prey’s position. This might help the orcas target the biggest fish, which they bring to the surface to tear apart, while the dolphins enjoy the scraps.
Friends and anemones
For some hermit crabs, a protective snail shell and serrated pincers are not protection enough, so they add stinging tentacles to their armoury. Like the shell they live in, the tentacles are borrowed, but from an anemone rather than a mollusc.
Some hermit species will actively detach anemones from rocks and place them onto their shells. There are also records of crabs transferring their anemone to a new shell when they outgrow the old one.
There are benefits for the anemones, too, which get to eat scraps from their hosts’ meals.
Boxer crabs go a step further. They spend their lives clutching an anemone in each claw, which they wave around to catch food and deter predators.
Unholy alliance
It takes a brave frog to share a burrow with a tarantula. One might expect such a large spider to relish the opportunity to eat a juicy little amphibian. And yet, around the world, many cases have been recorded of tiny frogs and enormous arachnids not only tolerating each other’s company, but apparently actively seeking it out
Although the frogs and the tarantulas are both predators, they are not teaming up to hunt. Instead, these unlikely relationships seem to be about mutual defence. The venomous spiders deter predators that might otherwise attack the frogs, while the frogs keeps the burrow free of ants, which are known to attack the spider’s eggs.
