I know: that sounds like sacrilege. How could someone who has loved and studied loons for over a quarter century make such a statement? Perhaps I can lessen the blow a bit by stating that loons are not alone. All animals, in fact, are essentially selfish. This is one of the most difficult concepts for many nature observers to understand about animal behavior.
I do not raise this topic just to be mischievous (although I suppose that is a side benefit). In the past two weeks, three people with whom I have spoken have tried to explain certain loon behaviors by first presuming that loons behave unselfishly — that their behavior somehow aims to help other loons or the entire species. So I felt it necessary to explain why such unselfish behavior should not occur.
What do I mean by saying that loons are selfish? I mean that when a loon — or a panther or a mosquito – exhibits some behavior, that behavior is, with rare exceptions, evolutionarily good for that animal. By “evolutionarily good”, I mean simply that the behavior increases the proportion of its genes in the population – its very own genes. In short, almost all animals behave so as to promote their own reproductive success, even if this comes at the cost of the breeding success of others of their species. Indeed, promoting one’s own reproductive success typically means suppressing the reproductive success of others, because others are competitors for mates, territories, food, and other resources that you need to rear your own offspring.
Why must animals behave so as to be genetically selfish, as I have stated? The easiest way to look at the problem is as follows. Consider a population of individuals of a species – like the set of all loons in Oneida County, Wisconsin. Imagine that a mutant loon appeared who began to forego its own efforts to breed and instead helped others compete for territory ownership or rear their young. While such altruism would win our hearts instantly, it would be a dismal failure in the evolutionary game. Why? Because this exemplary individual would rear no young that possessed that trait of helping others. So the next generation of loons would contain no loon that helped others in this way, and that pleasing altruistic mutation would quickly vanish from the population. This is the demoralizing truth about the evolution of behavior: selfish traits thrive; unselfish ones die out.
“Wait”, you are thinking. “Many humans are unselfish; we see altruistic acts every day; many non-human species show altruistic behavior as well.” This is a puzzle: if unselfish behavior is so harmful to an animal, why do we see so much of it in humans and other animals?
Yes, unselfish behavior — that which has a cost to the donor and provides a benefit to a recipient — is common in some animals, but only under a narrow set of conditions. First, we need to exclude all cases of unselfish behavior towards offspring. Protecting your own biological offspring from a predator or giving up food for their benefit is evolutionarily selfish, because they carry your genes. And now that we are paying attention to genes, rather than just whole individuals, we can expand our thinking and see that offspring are not the only ones that share genes with an animal. In fact, providing food or protection for any close relative might be viewed as evolutionarily selfish, and we might expect to see such behavior in many species. Why? Because, again, promoting the survival and breeding success of close relatives increases the likelihood that genes you share with them will survive and spread in the next generation. So we might expect unselfish behaviors toward close relatives – even dying to protect them in some cases – to be common as well. And they are. This is how we can understand food-sharing and joint group defense in species like honeybees, orcas, ground squirrels, Harris hawks, elephants, and termites – species that live in groups of closely-related individuals.
Unselfish behavior is not entirely dependent upon shared genes. Unrelated individuals can be unselfish towards one another as well. In fact, humans have a word for an unselfish relationship between unrelated animals: friendship. If a phenomenon is so familiar to us that we need a word for it, it must be real and important. Indeed, friendships are important and rather widespread in animals. Furthermore, they constitute an entirely new and different kind of behavior pattern, because giving an unrelated friend ten bucks, even if it helps them produce more young (!), does not help you at all through the friend’s reproduction. To see how unselfish behavior among non-relatives could evolve, we need the concept of “reciprocal altruism”, which is just a nerdy, scientific phrase that refers to friendship. The concept of reciprocal altruism holds that two individuals (of any species) might be expected to behave unselfishly towards one another (exchange unselfish acts), providing: 1) they know and remain with each other over a long period, and 2) each truly behaves unselfishly towards the other (i.e. unselfishness is a two-way street). In other words, if you give your friend food today, but you meet up again tomorrow, when you are hungry, and he gives you food, you have engaged in reciprocal altruism. This strategy is a sensible behavior pattern in cases where food or other resources are spotty but can be shared over time to the benefit of both animals. Reciprocal altruism occurs in many social species. One of the most well-documented cases is in vampire bats, in which unrelated friends reciprocally share blood meals over time such that survival is increased for both individuals.
How does this all relate to loons and their behavior? Loons, like most species of animals, are solitary breeders: they do not breed in clusters or colonies, or family groups. So there is little potential for unselfishness towards extended family or friends. The best opportunity for unselfishness in loons appears to occur when young males return to the vicinity of their natal lake at age three or four to look for a territory. Three years is a short time in this species; a returning male is likely to find one or both parents still on its natal territory when it visits there. But – and here is the kicker – we have not detected any difference between how parents’ treat their adult offspring and how they treat unrelated territorial intruders. In other words, we have no evidence that loons recognize their own young (or vice-versa) when the latter return as adults. To drive this point home in a rather unsavory way, we have had four instances in which returning sons have paired with and even produced offspring with their mother (always near their natal lake, never on it).
Thus, loons, like most other species of animals, do not look out for other loons. Behavioral ecologists like me have learned to view each animal as being on a sort of narrow-minded quest to maximize the number of its own biological offspring — regardless of the consequences of this selfish behavior for its population or species. If you can grasp this sad concept, you will be far above the average observer of nature. Perhaps, like me, you will feel somewhat compensated when you are able to tsk-tsk condescendingly the next time you hear an erroneous but well-intentioned nature video proclaim,“….and leopards never consume too much food, but instead leave enough to support others of their species.”