Why would two species of predator with the same prey cooperate?

Question

The question is pretty straightforward:

Why would two species of predator with the same prey cooperate?

I am looking for answers in the following context:

• Limited food supply, which means scarcity of prey and food
• Non-compatible species of predators which can not reproduce with each other
• Localized and small hunting ground, the prey are not widespread and only exist in a small area, the predators can not simply have different territories.
• The predators are roughly equal in number and power, and one does not have the advantage over the other - one can not simply destroy the other or consistently scare it away from prey. Any conflict between predators would be non-deterministic and dangerous for both.
• The prey can not be taken down easily, and multiple predators are required

With the context above, why would they work together? I want them to work together, I just don't know why would they?

I have not yet finalized these predators, I am looking for suggestions, or ways to modify or design them so that cooperation will work - maybe something symbiotic?

Answer 1

Eels and groupers hunt cooperatively. The groupers are good at finding and herding prey but bad at killing it. Eels are fantastic killers but bad at finding prey. To the point they rarely succeed without the other. And they have been show to actively signal the other. Grouper & eel cooperation

Honeyglider birds lead honey badgers to beehives. The birds can easily find the nests but can't tear open the strong hive, the badgers can tear open the hives but can rarely find them. The badger tears it open and eats then the bird flies in and eats its fill from the now open hive.

As was mentioned, humans and dogs are a classic example: dogs are fast and have good senses of smell, humans have good eyesight and are strong clever killers but fairly slow. Together, they can find prey better and dogs can easily drive prey to humans who can kill it easier than the dogs could alone.

Basically, all you need is for your two species to have a different suite of senses and/or physical capabilities.

Answer 2

Here's some footage from the BBC of dorado and frigatebirds hunting flying fish.

The dorado force the flying fish into the air, where the frigates catch them, the frigates scare them back into the water where the dorado catch them. The two predators are not directly competing as they don't share a medium of movement, and for each the presence of the other makes the hunt easier, as the prey can evade each one alone.

Answer 3

You can have them work like Badgers And Coyotes. Based on an article found here

Badgers and coyotes share a common predilection toward taking various burrowing rodents as prey, though they catch them in very different ways. Rodents such as squirrels and prairie dogs have no chance of outrunning a coyote, but they can always escape into their burrows. A badger, on the other hand, can dig into the ground and tear a rodent from its burrow provided the rodent doesn’t simply run out of another exit and leave the badger with no hope of catching it. A badger-coyote team could certainly tip the odds against their common prey if two competing predators could manage to work together.

Answer 4

Good manners started to happen as soon as all the mammoths were killed off and there was no piece of food big enough for everyone to eat at the same time (Nanny Ogg's Cookbook, © Terry Pratchett & Stephen Briggs)

As long as they can tolerate each other's company and there is a benefit - ANY benefit - to keeping it, the details don't matter as much, and what each thinks of the other - "brother" / "master" / "tool" / "supplier" matters even less. Doesn't have to make sense, as long as it works. Some benefit is had on average, and selection will have done its thing.

Even if one side is shortchanged due to food scarcity, such teams might still outperform singles.

Some ideas:

• one has poor mobility, another has poor offensive power. Think those crabs that use anemones, if they hunted live prey
• one is prey to something else, which is in turn kept at bay by the "partner", who benefits by having dibs on the food and/or having to exert itself less
• one side may be able to utilize scraps the other can't - like sucking out marrow.
• one side controls the other - feeding when possible, culling when not. Sad, but this does work even when they are theoretically equal in power.
• there are non-combat benefits - like pest removal, threat detection, crafting shelter or traps, etc

Further benefits can emerge in an already established partnership.

Answer 5

If you're looking for a more fantasy like answer, perhaps evolution has driven the two predators into a cooperative pact of some sort.

Say for example if the primary grazer of the area has, over the millennia, developed an exceptionally thick hide. The primary predators of this animal have included two species with very different methods of bringing it down. One, essentially a large predatory cat, would bring it down through mauling the prey and get the kill through sheer violence. The other, a large venomous lizard, would simply bite the prey in the leg, inject a lethal dose of venom, then just follow the beast until it fell.

Nowadays, with the grazer's hide being so thick, the cats take much much longer to take it down by themselves and the risk of getting bucked in the head or grievously wounded has become too high. The lizard too has problems, in that it's fangs has difficulties penetrating the thick outer layer to deliver it's venom.

The solution: These predators hunt in pairs. Now earning dinner is a co-op game. The cat will typically make the first strike, focusing on opening up a gash somewhere in the targets hide. The moment the lizard senses an open wound, it will pounce in and inject it's venom. Once this is done, both predators retreat to a safe distance and wait for their meal.

I don't have too hard of a time imagining a pact like this actually forming through natural evolution, and it could make for a fairly unique bond between the two creatures. Each one may even develop a tendency to try to form a lifetime partnership with the other.

Answer 6

At the top of the food/intelligence chain, BBC's Human Planet has an interesting section of Humans and Dolphins fishing together in Brazil.

Also one of their other shows (maybe Planet Earth? not sure) has video of sea snakes and trevally (a predatory fish) hunting together in a reef.

In both cases, the two predators have complementary skills that are used in conjunction. Dolphins move well in the ocean and like to drive fish up against a beach to make them easier to trap. Humans don't move well in the ocean, but can make nets to trap the fish. Sea snakes can get fish out of tight crevasses, while trevally are fast enough to catch fish that try to scoot away.

Answer 7

Wolves and Ravens

Allegedly Ravens lead wolves to large animals that are too large for the ravens to kill (Ravens can kill sheep). The Ravens then get a share of the spoils. In this instance the Ravens are acting as scouts and improving the odds of the wolves getting a kill and the ravens getting a meal. (See Mind of the Raven: Investigations and Adventures with Wolf-Birds)

Answer 8

Orcas have been known to cooperate with whaling boats]1. If they are after the same prey but not in competition over who gets what, there is a lot of benefit in cooperation. In that case the orcas would get the tongue and lips of the killed whale and the whalers would get the rest.

Answer 9

As other answers have suggested, mutual benefit is the likely reason. If both species mutually benefit from co-operating (or at least tolerating) each other, the trend of doing so will develop.

Aside from complimentary hunting skills, it might be worth mentioning the potential mutual benefit of co-operation afterwards.

With a scarcity in prey and food you can be certain there will be plenty of opportunists and scavengers, ready to pounce on someone else's kill.

And so the pair, instead of competing, take turns acting sentry and guarding the kill to ensure that the other one can eat undisturbed - minimizing the amount lost to scavengers. Over time, both predators benefit from having less of their kill stolen.

Answer 10

What about a situation where both predators eat/use different parts of the same prey, but cannot individually get to them. Say predator A can kill the prey, but for whatever reason cannot get to the marrow (or whatever) that it actually needs. Predator B cannot kill the prey, but is evolved to open the bones and expose the marrow (or whatever) but does not consume the element that predator A needs.

That is not a perfect depiction but you probably get the idea. Only if they work together can they both get what they need. You could make it as "magical" as you want too if that's appropriate to your setting... predator A is a hulking dangerous brute that subsists on "life energy" that it cannot properly release from the bodies of the prey, and it must not actually kill them or the life force is lost. It must merely incapacitate. Then predator B, which could never incapacitate the prey on its own, he some mechanism whereby it feeds off of resonances (not the life force itself... perhaps fear?) released during a creature's last moments, which also releases the overall life forces that predator A needs.

Can make this as real-world or fantastical as you wish.

Answer 11

Another way the two species might gain mutual benefit is protection from another species. For instance, you might favour hyenas if they'll drive away the lions and eat less- more for you.

Answer 12

I see the prey animal as large with a tough skin. Think about a Rhino or a Hippo. Predator A is a semi solitary Omnivore like a bear that only really wants the bones and maybe some other "cast off" parts of the prey animal. I think of Predator A as being large and somewhat slow.

Predator B would possibly be more catlike. Sharp teeth and claws and would be more interested in the soft, squishy bits. Maybe Predator B should be a Pack hunter.

Either Predator would be able to take the prey animal by itself, but with a lower success rate. Predator A would be able to kill the Prey quickly, but is not really suited to chasing it down. Predator B could easily chase it down, but the tough hide make an quick kill unlikely and would be risky for predator B's survival. Either way the effort required for either predator species is high.

Prey animal slowly displaces other potential prey animals, becoming the most likely source of food for the 2 predators. One Day, a pack of predator B realizes that it can herd a large member of the Prey toward the den of predator a. Predator A dispatches the animal without having to chase it. Predator B gets to eat with less effort and risk. Marinate this sequence over several millennium and you have actively cooperating predators.

The keys here are that the predators each want something different from the prey, and that the prey be difficult, but not impossible for either predator to take on it's own.

Answer 13

Probably because the two can do different things better.

For example, lets have a really fast spider, that can make large webs quickly, and catch up with it's prey, and a larger, stronger, but slower meat-eating-sloth-thing. The spiders stop the prey, and trap it, and the sloth comes and kills it. The spiders are in danger if they try to kill it, because of their exoskeleton; in Spellsinger, whatsisname punches a giant spider, and it dies from a blow that would only have made a human angry.

Another possibility would be if one can catch, stop, and possibly kill the prey, but can't pierce its skin, and the other can't catch the prey, but can carve it. That way, they have to work together.

Answer 14

This has probably been touched on, but the best reason I could think of would be some sort of co-operation. Maybe both predators have different but complementary ways of hunting and they've learned to use each other. If you're envisioning an environment where land and food are rare, there aren't many better examples to use than that of the African desert and grasslands. When you think of this environment, you'll notice that the main prey animals have something in common. They are either very big, very strong, very fast or a combination of all three. This means that they are almost impossible to kill. What does this mean for our predators? Well, there are probably a couple of benefits.

Overwhelming Numbers

One of the best ways to take down large prey is through large numbers. Wolves are probably the best known land example, but you probably didn't realize that Orcas have been known to kill animals as large as blue whales through tag-teaming efforts involving the whole pod relentlessly harassing the larger whale for hours or even days. Maybe your environment doesn't allow for one species to reach the numbers needed to take down prey this way, but having the two species working together gives them the numbers edge. And since they don't need to expend as much effort, sharing their food with another species isn't a big deal.

Specialized Tools

Another benefit could be that each species has a very specialized and complementary hunting technique. Maybe one hunter is very good at killing the prey but lousy at catching it, while the other is great at catching prey but lousy at killing it. Once again it comes down to the fact that when it's easier for each animal to get the food, sharing some doesn't matter as much so long as both are benefiting.

The Parasite

What if neither of those points mattered? Is there still a way you could have two predators eating from the same food source? Simple, make one of them a predator and the other one a parasite. I'm not talking something like worms or ticks, have one of the predators specialize in stealing food from the other one. Maybe they are very quick and strong for short bursts and can follow the other predators around, waiting for them to make a kill before swooping in and stealing the food. Maybe one of them could be some sort of big cat/dog and the other could be a large eagle that flys in and grabs smaller prey whole and chunks of bigger prey. It's not exactly co-operation, but it could make for an interesting story point, especially if both predators are sentient in some way.

Answer 15

Lions and wolves both hunt in packs to take down larger game they they can handle individually, so cooperation within a species is established. The question is how to extend this. If another factor prevented high densities of each of your predator species, the only way to gang up on prey would be to gang up with the other species. Perhaps suitable breeding/sleeping locations are sparse (tree-nesting apes needing big trees, anything needing caves) and the animals are territorial.

Alternatively a vulture(-like-creature) could prevent a turkey from taking flight allowing it to be killed by a cat that then shared the meal -- the vulture couldn't strike the turkey on the ground, and the cat couldn't in the air. A similar approach would work at the margin of land and water or air and water.