In 'The politics of animal cooperation' Thomas Jay Oord (June 1, 2003) wrote:
In contemporary science, biologist Alan Dugatkin’s work in animal cooperation validates Kropotkin’s words. Dugatkin’s book Cooperation Among Animals: An Evolutionary Perspective offers numerous examples of friendship among nonhumans.
The social activities of birds, for instance, illustrate the great degree of cooperation found in the nonhuman world. Birds regularly hunt together and provide information to one another about where food can be found. In addition, many species of birds provide warnings about predators, thereby establishing a means by which they can survive and thrive through cooperation. In fact, many other animal species both hunt cooperatively and work together to warn others as to the whereabouts of predators.
Perhaps the clearest example of friendship among animals is the mutual grooming that occurs in many species. As early as the 1930s, primatologists documented the mutual benefits that grooming affords nonhuman primates. Recent studies have shown that primates enjoy numerous benefits from cooperative grooming. The practice removes parasites, reduces emotional tension, fosters relational bonds, and can be a commodity to exchange for other benefits.
After surveying the research related to cooperation in fish, birds, insects, and mammals, Dugatkin concludes that, “while not ubiquitous, cooperation is certainly widespread in the animal kingdom and sooner or later we will . . . come up with a solid fundamental understanding of the evolution of cooperation.”
Of course, the best examples of friendship-love available to science come from the friendships among human primates. The scientific disciplines of sociology, psychology, and anthropology provide rich data from which to articulate theories of philia. Of course, human cooperative friendship is often much richer and more complex than nonhuman cooperation, because humans possess superior capacities for language, rationality, consciousness and long-term planning. The social sciences provide plenty of evidence to support Ralph Waldo Emerson’s claim that a human friend “may well be reckoned the masterpiece of nature.” http://www.google.co.uk/search?q=competition+cooperation+animals&hl=en&start=60&sa=N