As a behavioral ecologist at UCLA, I sometimes give a lecture about surfing and sharks. While most of my students don’t surf, the example illustrates a pertinent point about human survival and risk.
Any risk of predation you face surfing alone drops in half when you surf with another person, I explain, since you can assume that a shark will, at most, eat only one of you. Surfing with two companions drops your risk to a third, and so on.
I use the surfing example not because sharks kill a lot of people—they don’t, globally there are about 64 unprovoked shark attacks a year—but rather because it makes an impression. We pay attention to things that can kill us, particularly if it’s in a gory way!
The important idea I want my ecology students to understand is this: When assessing and facing risk, working with others and forming cooperative alliances serve us, especially in our defense against adversaries.
As alliances shift in the new world order forming today—and with our collective memory about the costs of war and the costs of tariffs fading—we must maintain perspective on what cooperation gives us.
We humans evolved from a long line of successful non-human ancestors who passed down lessons about cooperation and collaboration. While some predators, like wolves, lions, and wild dogs, are able to cooperatively hunt larger prey, the ungulates (deer, zebra, and gazelles) that they eat have themselves evolved to form groups to protect against predators. But for us, and in many species, cooperation has evolved slowly, and with difficulty. Living with others requires sharing resources—in the same way that surfing with others means sharing waves. Still, many animals, from reef fish to large herds of mammals, work alongside others at the potential cost of getting less for themselves. Why?
Because it’s safer. If you’re in a group searching for food in a risky area, someone with you is apt to detect a predator and deliver a warning in time; a solitary individual foraging alone is more likely to be surprised by a predator, and less likely to escape. In cases where a whole group escapes together, the ensuing confusion may make it more difficult for a predator to focus on a single individual and make a successful kill. Studies have also shown that individuals foraging in groups may be able to allocate less of their time to searching for predators and may actually be able to spend more time foraging. Cooperation provides safety, and sometimes more access to resources.
Collective defense reduces costs to each actor—whether it’s a deer, a dolphin, or a country—and therefore benefits them all. If you’ve ever seen little songbirds chasing a crow, or crows and ravens chasing hawks, you’ve witnessed mobbing, one form of this behavior. Many bird species have evolved specific vocalizations to recruit others to help chase away predators; these rapidly paced, noisy, easily detectable, and localizable sounds are known as mobbing calls, and we know that they work. When you hear a bird actively mobbing a predator, others often join in the chase.
These lessons from nature should show us there is value in creating alliances—even between very different actors—especially when they share a common threat.
We also see cooperative antipredator behavior between members of different species. My colleagues and I study mixed-species flocks of Amazonian birds. These groups are defined by a sentinel species—antshrikes, which produce alarm calls when they detect a predator—joined by a variety of other species that defend territories from other mixed-species flocks. Working their way through the forest, each species does something a bit different. Some, including antwrens, perch high up and glean insects off leaves. Other species march on the forest floor eating ants.
Our current work shows that members of the flocks provide each other information about when it’s safe to forage, which permits all animals to forage more than they would had they not worked in groups. This type of interspecies cooperation is a highly effective strategy that helps the different species of birds survive and prosper. Indeed, my colleagues have previously shown, the territories that these flocks defend can be stable over decades.
Cooperative alliances are often difficult to maintain. Theoretical modelling shows that some form of punishment is essential if a cooperative partner “defects” or “cheats” and doesn’t engage in the norms or habits of cooperative behavior. Initially, behavioral ecologists thought that tit-for-tat strategies—where actors were immediately punished for defection–was the best response. For instance, impalas (an African ungulate), take turns grooming each other’s difficult-to-reach places, but should one of the impalas stop, the other will not reciprocate and walk away. However, this tit-for-tat strategy only works if you’re playing relatively short and one-off cooperation games. Many social bonds and relationships are substantially longer like those seen in vampire bats who, after forming relationships through grooming, may share a blood meal with a hungry grooming partner.
When there are benefits from longer-term associations, some degree of additional tolerance of cheaters works better (e.g., tit for two tats). But at some point, the models suggest, punishing or no longer cooperating with a cheater are the only options left for a spurned cooperator. As we know from our human world, we’re more likely to tolerate more misbehavior from close relatives than from unrelated people. But in an alliance, unlimited tolerance of poor behavior is never a good idea.
These lessons from nature should show us there is value in creating alliances—even between very different actors—especially when they share a common threat. Cooperation makes us safe, and the security it provides helps us prosper. We’ll do better sharing waves.
Daniel T. Blumstein is a professor in the ecology and evolutionary biology department and the Institute of the Environment and Sustainability at UCLA. His most recent book, The Nature of Fear: Survival Lessons from the Wild, was published by Harvard University Press.
Primary editor: Talib Jabbar | Secondary editor: Eryn Brown
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