Stephen Jay Gould, in his intrepid war against anthropocentrism, has asked why, if mammals are so superior to reptiles as many have claimed, from the Permian to the end of the Cretaceous mammals remained small, rodentlike creatures but reptiles exfoliated into a tremendous variety of creatures, including the largest ones ever to have inhabited the earth. Even though mammals were warm-blooded and therefore presumably faster than reptiles, and had a considerably larger brain compared to body mass than reptiles, for a very long time they didn’t seem to have much to show for it. If it were not for the extinction event some 65 mya, Gould notes, we (because we are mammals, speaking of our ancestors as “we”) might be coexisting with, or rather scuttling around the feet of, much larger reptiles to this very day, or, if we confine “we” to human beings, we would not be here at Only when really large reptiles (dinosaurs) were wiped out did the mammals finally come into their own and provide the megafauna of the more recent period.
A cautionary footnote here might be in order. Large size may open up possible new capacities, but large size is vulnerable. Mammals (and birds) were small, and like small reptiles such as snakes, lizards, and turtles, proved viable enough to survive the Cretaceous-Tertiary extinction event, as did, of course, the single-celled organisms. We don’t usually think of humans as megafauna, but we are still on the large size if one looks at life as a whole, thus surely vulnerable to extinction in the case of a catastrophic event. Megafauna are variously defined, but the term is often used for any animals weighing more than a hundred pounds, and is widely used for any animals larger than humans. Ouch.
Though we will be primarily concerned with how mammals developed, especially since the Cretaceous-Tertiary extinction event 65 mya, we do need to say a word about birds, because birds developed, quite independently, some of the same capacities as mammals. Birds split off from dinosaurs in the Jurassic period, roughly 200 to 150 mya. By heredity they could still be called dinosaurs, the only dinosaurs to survive the Cretaceous-Tertiary extinction event. They are a highly successful class of animals, consisting of around 10,000 existing species, existing in every continent and region of the globe. Like mammals, they are warm-blooded, have a rapid metabolism, and need to have a large food intake to sustain their body heat and active life. Relative to body size, they have large brains, and some of them are quite intelligent-some crows even make tools. Most of them, like most mammals, are nurturant toward their offspring, building nests in advance of laying eggs, keeping the eggs warm by their body heat, and feeding their often helpless chicks until they are ready to take care of themselves. Most bird species are socially monogamous, and care of the eggs and the chicks is often shared between the parents, perhaps more often than among mammals. They have vocal capacities unmatched by all but a few other species, and use complex visual and aural signaling. Although the study of animal emotions is difficult and controversial, birds seem to share the capacity for emotion with mammals in a way that few other species do.
Mammals are warm-blooded, unlike reptiles but like birds, which means that they can inhabit regions so cold that reptiles could not survive in them. Most mammals also have hair or fur, which enables them to survive in cold climates. The very word “mammal” comes from the mammary glands, which seem to be unique to mammals. In the females of the species these glands produce milk for offspring, which are born alive. Even monotremes, the survivors of a very early mammalian line that reproduces by laying eggs, have mammary glands, whose purpose is not clear. Marsupials give birth to live offspring, but these are placed in the mother’s pouch until they are able to function on their own. The great majority of mammals are called placental, as the embryos develop within a placenta in the mother’s body. All placental newborns must suckle from their mother or some other female if they are to survive, but there is a difference between precocial species, in which the young are relatively mature and mobile from the moment of birth, and altricial species, in which the young are born helpless. The same difference is found in birds: there are a few bird species where the chicks are able to peck their way out of the egg and be on their own, but most require some degree of nurturance, in some cases quite extended.
I want to focus on parental care, a capacity that correlates with several other developments that have enormous potentiality, as Sarah Hrdy has pointed out. Just to name a few: increasing intelligence, sociability, and the ability to understand the feelings of Related to this complex is what Frans de Waal calls “the co-emergence hypothesis,” which describes the appearance at a certain point in human childhood of the capacity to recognize oneself in a mirror and thus have a sense of “positioning oneself in the world” at the same time that the child becomes capable of understanding that others, though separate from the self, have the same kind of feelings as oneself and so can be responded to in terms of their feelings, what de Waal calls “advanced empathy.“54 But de Waal does not mean that these interrelated capacities necessarily arose at the same time in evolutionary history or that they are confined only to humans:
We are part of a small brainy elite that operates on a higher mental plane than the vast majority of animals. Members of this elite have a superior grasp of their place in the world and a more accurate appreciation of the lives of those around them. But however tidy the story may seem, I’m inherently skeptical of sharp dividing lines. For the same reason that I don’t believe in a mental gap between humans and apes, I can’t believe that, say monkeys or dogs have none, absolutely none, of the capacities that we’ve been discussing. It’s just inconceivable that perspective-taking and self-awareness evolved in a single jump in a few species without any stepping stones in other animals.55
To relate de Waal’s co-emergence hypothesis back to parental care, let us consider a comment of de Waal about the origin of empathy:
Empathy goes back far in evolutionary time, much further than our species. It probably started with the birth of parental care. During 200 million years of mammalian evolution, females sensitive to their offspring outreproduced those who were cold and distant. When pups, cubs, calves, or babies are cold, hungry, or in danger, their mother needs to react instantaneously. There must have been incredible selection pressure on this sensitivity. Females who failed to respond never propagated their genes.56
Sarah Hrdy notes that some degree of parental care, usually from mothers but sometimes from fathers, can be found among fish, squid, crocodiles, and rattlesnakes, and notes: “Wherever parental care evolved, it marked a watershed in the way animals perceived other individuals, with profound implications for the way vertebrate brains were structured.” But then she points to the special development of parental care among mammals:
Nowhere have these cognitive and neurobiological transformations been more revolutionary than among mammals. Mammal mothers fall in a class by themselves. Lactating mothers date back to the end of the Triassic, around 220 million years ago. This is when babies began to be born so helpless that mothers needed to be attuned to the smell, sounds, and slightest perturbations in the conditions of vulnerable young that had to be kept both warm and fed. Since any nearby newborns were likely to have issued from their own bodies, it was adaptive for mothers to perceive all neonates as
The capacities that develop from the emergence of parental care are absolutely basic to the entire story I want to tell from here on, basic to the development of empathy and ethics, even among many species of animals, and ultimately religion among humans. However, it is important to remember that many other things were developing too. Aggression is to be found in almost every animal species (the bonobos may be the great exception, though even they can be quite unpleasant), and though much of this aggression can be interpreted as adaptive, much of it seems quite senseless, an end in itself gotten out of control. De Waal, in trying to defend himself from seeming to ignore the darker side of evolution, notes, “There’s plenty of one-upmanship, competition, jealousy, and nastiness among animals. Power and hierarchy are such a central part of primate society that
conflict is always around the corner.” Yet just because others have emphasized this dark side, “nature red in tooth and claw,” de Waal insists that we also recognize that that is never the whole story, and points out: “Ironically, the most striking expressions of cooperation occur during fights, when primates defend one another, or in their aftermath, when victims receive solace.“58
I would like to turn to the work of an earlier ethologist, Irenaus EiblEibesfeldt, to discuss some of the wider implications of parental care, implications that have recently been further spelled out by scholars like Hrdy and de Waal. As indicated by the very title of one of his best-known books, Love and Hate, Eibl-Eibesfeldt does not minimize the importance of aggression in the evolution of behavior. Following Konrad Lorenz and others, he notes that aggression is older than love and is, for example, found among reptiles, while love is not59 He also sees aggression as a site, curiously enough, for the development of ethics, even among reptiles, as we will note in a moment. But the origin of love he finds in parental care, which “unites the parents with their offspring and is clearly excellently united in reinforcing the bond between adults. We drew attention to the fact that only animals that care for their young have formed closed groups. They all do it by means of behavior patterns of cherishing which originate from parental care, and by making use of infantile signals which activate this behavior.“60
Eibl-Eibesfeldt sees parental care as the basis not only of group bonding, but of individual friendship: “There is also, with few exceptions, no friendship without parental care.“61 He points out that friendships are initiated by behavior that draws on the repertory of parental care, as does, even more clearly, courtship behavior. Nuzzling, real or pretend feeding, kissing, are all borrowed from the repertory of parental care.62 Eibl-Eibesfeldt seems to see sexuality and parental care as separate sources of bonding, with the latter more powerful than the former, but it would take only a cursory knowledge of Freud to see that these can be deeply related motives, though by no means always so.63
It would be possible to draw many more examples from Eibl-Eibesfeldt’s rich natural history, of the way in which almost every form of love draws its substance from the repertory of parental care. He also notes that what he calls the flight drive, the natural response of a startled animal to seek refuge with a conspecific, particularly the most powerful conspecific available, is rooted in the child’s rushing to its mother at the first sign of something unusual.64
Still, we must not forget the ubiquity of aggression. It would be well to take a glance at Eibl-Eibesfeldt’s argument about aggression alluded to above, that relates it to norms that derive from self-preservation rather than love. What he calls ritualized aggression is found in many animals, including reptiles: “Fighting animals have often developed very complicated rules of combat that make it possible for them to fight without shedding blood.” He gives the example of the marine iguanas of the Galapagos Islands: “The bloodless tournament begins with a threat display: the occupant of the territory raises the crest on his neck and back and shows himself to his opponent broadside on.” He raises himself from the ground to make himself look larger, makes biting gestures and waves his head. If the intruder does not retreat, the defender rushes at him and they butt heads and try to push the other from the spot. The “fight” ends when one successfully pushes the other away, or when one acknowledges defeat by lying on his belly in a submissive gesture. Though they have large, sharp teeth and powerful jaws, no blood has been shed. EiblEibesfeldt notes, “Rattlesnakes never bite one another, and rivals fight under strict rules.” (And these rule obeyers are reptiles!) Similar ritualized fighting occurs in birds, fish, and mammals. We will need to consider such normative behavior further along. Eibl-Eibesfeldt points out the obvious adaptive explanation: fighting to the death could quickly eliminate fertile young males from the population, leading to early extinction.65
What Eibl-Eibesfeldt (or his translator) so charmingly calls “cherishing” behavior in the earliest and simplest examples of parental care must surely also have been adaptive, as de Waal and Hrdy noted above. But the fact that love in this rudimentary sense is “functional” does not mean that the extraordinary developments that ensued are mere functions of its origin. Hrdy writes, “Natural selection has no way to foresee eventual benefits. Further payoffs cannot be used to explain the initial impetus.“66 That parental care would lead to social bonding, the possibility of individual friendship, and even, eventually, to marriage and the family, are all unforeseen, and, though in turn adaptive, have given rise to meanings that go beyond adaptation. To find the origin of love in the adaptations of the earliest mammals and birds is not to reduce it to those origins but to marvel at the ways of nature in leading to something so central to our lives. Nonetheless, what humans have done with the practice and ideal of love should in no way make us overlook the whole evolutionary history or put down other species for not quite reaching some of the advances of our own. Frans de Waal makes the point that we cannot really understand ourselves if we limit our concern to our own line of development, even if we go back 2 million years to the increasing size of our frontal lobes: “Empathy is part of a heritage as ancient as the mammalian line. Empathy engages brain areas that are more than a hundred million years old. The capacity arose long ago with motor mimicry and emotional contagion, after which evolution added layer after layer, until our ancestors not only felt what others felt, but understood what others might want or
As de Waal indicates when he speaks of “motor mimicry,” empathy is in the body as much as in the head. It is in the body “where empathy and sympathy start-not in the higher regions of imagination, or the ability to consciously reconstruct how we would feel if we were in someone else’s situation. It began much simpler, with the synchronization of bodies, running when others run, laughing when others laugh, crying when others cry, or yawning when others And when empathy reaches the point of human love, though it is indeed in our heads, it is still very much in our bodies. As de Waal puts it: “Bodily connections come first-understanding follows.“69 To use the terms of Chapter 1, love is always, in part, enactive.
De Waal’s approach helps him overcome a distinction that has become basic in much biological theorizing, though it arose from philosophical speculation-the distinction between selfishness and altruism. He gives the example of an animal mother, annoyed by the loud audible complaints of her pup, who suckles or warms it to shut it up. In such a case, “we can’t exactly call empathy `selfish,’ because a perfectly selfish attitude would simply ignore someone else’s emotions. Yet it doesn’t seem appropriate either to call empathy `unselfish’ if it is one’s own emotional state that prompts action. The selfish/unselfish divide may be a red herring. Why try to extract the self from the other or the other from the self, if the merging of the two is the secret behind our cooperative behavior?“70
He spells out further the “merging” aspect of empathy: “We can’t feel anything that happens outside ourselves, but by unconsciously merging self and other, the other’s experiences echo within us. We feel them as if they’re our own. Such identification cannot be reduced to any other capacities, such as learning, association, or reasoning. Empathy offers direct access to `the foreign self.“171 And the capacity for such identification can cross species lines: “The whole reason people fill their homes with furry carnivores and not with, say, iguanas or turtles-which are easier to keep-is that mammals offer us something no reptile ever will: emotional responsiveness. Dogs and cats have no trouble reading our moods and we have no trouble reading theirs.“72
Given that many in our insanely individualistic American society would doubt that such empathy is possible, it should be more widely known that not only is it basic for human beings but that other animals have shared it for over a hundred million years. Just as “altruism” is a term that has invaded biology from philosophy with mixed results, so has the more recent philosophical idea of “theory of mind,” the capacity to know what others know. D
e Waal calls it “cold perspective-taking” because it focuses on what another individual knows or sees, not with what the other wants, needs, or feels. For all his concern not to draw sharp lines between humans and other animals, or between different animal species, and in spite of the fact that the latest studies do show that apes in some situations are able to grasp the mental states of others, he is willing to admit that “the advanced forms of knowing what others know may be limited to our own species.” Yet he feels that this is a “limited phenomenon” compared to the capacity to share the other’s situation and emotions.73 In other words, empathy remains a fundamental resource for a social animal such as ourselves, even though we also have more sophisticated ways of knowing.74
There are many other behavioral features besides the centrally important capacity for empathy that humans share with other animals and most especially with the great apes. Frans de Waal has probably done more than anyone else to describe these fascinating continuities in a series of important books.71 But with limited space and the need to get to the genus Homo and the species Homo sapiens, I will limit myself to one other area that we share widely with other animals and that I believe is critically important for understanding the origin of religion-namely, play.
Religion in Human Evolution: From the Paleolithic to the Axial Age Page 12