Intelligence in Nature - Jeremy Narby [16]
A wide variety of new research suggests that chimpanzees have culture and use language, dolphins recognize themselves in mirrors, crows make standardized tools, vampire bats reciprocate in food sharing, and parrots answer questions in ways that appear to mean the same to them as they do to people.
Alex, an African Grey parrot living in a lab in Arizona, can count up to six and recognize and name more than one hundred different objects, as well as their color, shape, and texture. When considering two objects, Alex can tell which is bigger or smaller and what attribute is the same or different. If presented with two yellow pencils and asked, âHow different?â he replies, âNone.â But when asked, âHow many?â he answers, âTwo.â Even when questioned by strangers about objects he has never seen before, Alex answers correctly eight times out of ten. He can also express his desires, squawking, âCome here!â when demanding attention, or âWanna go chairâ when bored with his perch. He also turns his back on people and says, âNo!â when he gets tired of being questioned. Alex, who was picked up at random in a pet store, does not appear to be particularly remarkable among African Grey parrots. Nor do parrots appear to be exceptionally smart birds. The difference between Alex and other talking birds lies in training methods. Alexâs trainer, scientist Irene Pepperberg, used techniques based on what birds do in the wild. Young parrots appear to learn their vocalizations by watching their peers and parents. Pepperberg trained Alex by letting him watch her teach another person. He now performs on cognition tests as well as dolphins and chimpanzees. Alex has a brain the size of a walnut, but he means what he says.
Even creatures with tiny brains have astonishing capacities. For example, leaf-cutter ants, with brains the size of a grain of sugar, practice underground agriculture and use antibiotics wiselyâand appear to have been doing so for fifty million years. Living in South and Central American rain forests, these ants feed themselves by getting around plant defenses with the help of a mushroom. They cut vegetation, scrape away plant antifungal defenses such as the waxy coating of leaves, chew the leafy matter into a pulp, and use it as a substrate on which they grow their fungal crops. In turn, the fungus does away with the insecticide substances contained in the leaves, which it digests, and which are absent from the mushroom tissue eaten by the ants. A leaf-cutter nest is mainly underground, an excavated warren with thousands of chambers filled with gray fungus. Warrens can reach the size of a human living room and house up to eight million ants. The fungus is the antsâ main food, and they make a monoculture of it. This puts their underground farms at the mercy of parasites and pests. One parasite in particular is a devastating species of mold that is found only in ant fungal gardens. Leaf-cutter ants do not just weed, manure, and prune their fungal crops; they also work constantly to keep the parasitic mold in check. To do this, scientists recently discovered, they use Streptomyces bacteria, which they carry on specialized parts of their bodies. This particular bacterium is the source of half the antibiotics used in medicine. Ants appear to have been using antibiotics on their fungal crops for millions of years without developing the pathogen resistance that plagues human use of antibiotics. How could they do this without a form of intelligence?
Defining âintelligenceâ is problematic, and I spent several days looking into the question. I found that intelligence has often been defined in terms of human capacities. Definitions include: âthe ability to solve problems or to create products that are valued within one or more cultural settings,â or âa biopsychological potential of our species to process certain kinds of information in certain