Bambi's real family

kw: book reviews, nonfiction, animals, natural history, memoirs

I got to wondering some time ago, are there any herbivores that are asocial? Among carnivores, social species are less common than asocial ones, but we typically see cattle, antelopes, and deer in herds, and even rabbits and mice live in groups, though we less often see them in numbers because they stay so hidden. The only ungulate that seems to be solitary is the moose. The term "moose herd" seems off somehow, though moose are probably more like elephants, for whom the females herd together while the large males are more solitary. Large males, whether elephant or moose, have no natural enemies and don't need the security provided by a group.

Reading The Hidden Life of Deer: Lessons from the Natural World by Elizabeth Marshall Thomas, I find that deer are indeed quite social, but their sociality has been overlooked by most, because of the primary focus on them as a hunted prey animal. The author notes that nearly all studies of deer "society" focus on aspects that a hunter can take advantage of, and that nothing she had read prepared her for observing the hierarchical rules the deer enforce.

The clearest example is feeding behavior with a limited resource. Ms Thomas had begun feeding turkeys in winter, a wintertime in which there were nearly no acorns (oaks do this periodically), to find that deer were also coming for the corn. She laid out more corn and began to observe, trying to discern individuals and their relationships. Because deer in winter are very hard to tell apart, except for size—and who can reliably gauge size when an animal is not right next to another?—she suddenly realized one day that their associations were a more reliable guide to identity.

Among the twenty to thirty deer that regularly visited her feeding area, she found there were at least four groups, each led by a mature female, presumably the mother and grandmother of the rest of the group. As in elephant society, the grown males are either solitary or form small bachelor groups, though these are much less cohesive than the female-plus-offspring groups. An animal seen alone was hard to identify, but when the group was together, the individuals could be easily distinguished.

She called four of the matrilineal groups she identified Alpha, Beta, Delta and Tau. Though this naming was in order of identification, it turned out to be an order by status also. The Alpha group always got the most food, and attempted to prevent all others from feeding if the amount was not sufficient for all. Astoundingly, to me, the other deer went along with this, to the point that, when the Alphas were done feeding and left the area, all the deer would leave, even some who might not have eaten at all. Only very late in winter, when the lower-status deer were getting desperate, would they return at an off time to scarf up some leftovers.

Throughout the book the author discusses the ethics of feeding. She found that she was one of about a hundred customers for winter corn at the mill (where she bought corn in hundred pound lots); the proprietor presumed that most of his customers were feeding deer. She looks at all creatures, even plants, as having the same needs for nourishment and reproduction.

Animals are capable of desire, while we think plants are not. Then she outlines the life history of the fungus Cordyceps, which actively invades an insect's body, eats only non-essential organs until they run out, then eats a portion of the insect's brain—apparently the self-preservation part—so that the insect climbs as high as it can on a twig or bush; the fungus then consumes the rest of the insect and sprouts from the shell, now in a high location from which its spores can travel far and wide. Is this purposive behavior? In a FUNGUS? Maybe we need to rethink whether non-animals have a brain, just of a different sort (and I once read an article that compared the tips of twigs to animals that had to move about by leaving a "trail" of lengthening branch behind, but observed on their own time scale, were quite active).

Finally, the author records an experience from the following winter. There were plenty of acorns, so she did not put out any corn. The first truly cold, blustery day, the flock of turkeys came, milled about the former feeding area, then stalked over to the house and looked at her through the window for a while. Later, two groups of deer did the same thing. They remembered her, and what she had done, and all seemed to be asking, "What will you do this winter?" Though herbivores are called small-brained, by comparison to carnivores, their brain is big enough!