NATURE

Partners for Life

One of the best supporting actors in NATURE's INTIMATE ENEMIES, the story of lions and buffalo in Tanzania's Ruaha National Park, is the brightly colored oxpecker, or tickbird. These slender tufts of feather ride serenely atop or clinging to the flanks of buffalo, with up to a dozen birds sometimes sharing a single animal.

The oxpecker's behavior fascinated early European scientists, who were mostly trained to think of the natural world as a constant competition between species, "red in tooth and claw." But here were two animals apparently cooperating in a very intimate way. Indeed, the partnership has major benefits for both animals. The birds get a ready supply of food, feeding on the ticks, flies and maggots from the buffalo's hide. The buffalo, in return, get some relief from pests and a free "early warning" system, since the birds hiss when lions and other predators approach, alerting their hosts to possible danger.

Biologists call such close-knit cooperation "symbiosis." In symbiotic relationships, two organisms of different species work together. While the buffalo-oxpecker relationship is one of the most famous symbiotic relationships, other important partnerships include the bacteria that live in our intestines and help us digest food, the bacteria that help some plants draw nitrogen from the soil, and the ants that "ranch" aphids, exchanging protection for a steady supply of the nectar that the aphids produce.

Although the concept was once controversial, many researchers now believe cooperation, or symbiosis, is just as important as competition in the natural world. As the buffalo and the oxpecker illustrate, joining forces is sometimes the best way to survive.


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