© Serge Bloch
On these taxing days, when we become a defiantly bipartisan nation of whiners convinced that we are handing over to the Internal Revenue Service our blood and sweat and mother's milk, our pound of flesh and firstborn young, maybe it's time for a little perspective.

Legions before us have donated all these items and more to the public till, and not just metaphorically speaking, either. Benjamin Franklin was right to equate paying taxes with a deeply organic behavior like dying. It turns out that giving up a portion of one's income for the sake of the tribe is such a ubiquitous feature of the human race that some researchers see it as crucial to our species' success. Without ritualized taxation, there would be precious little hominid representation.

Moreover, plenty of nonhuman animals practice the tither's art, too, demanding that individuals remit a portion of their food, labor, comfort or personal fecundity for the privilege of group membership. And just as the I.R.S. depends on threat of audit as much as it does on anybody's sense of civic responsibility, so do other toll-collecting species ensure compliance by meting out swift punishment against tax cheats. For example, Marc Hauser of Harvard University has found that when a rhesus monkey is out foraging and comes upon a source of especially high-quality food, like, say, a batch of ripe coconuts, the monkey is expected to give a characteristic food call to alert its comrades to the find. "The bad thing about doing a food call is that it means others will come and take some of the food," said Laurie R. Santos, who studies the primates at Yale University. Yet a monkey who opts to keep mum about its discovery could face worse. Should other group members happen by while the private feast is under way, they will not only claim the food for themselves, but the most dominant among them will also beat the cheater indignantly.

Not everybody is subject to a big macaque attack. Adolescent males that have only recently transferred into the group are not required to issue food alerts. They are, as yet, on probation, and only upon gaining the rights of full citizenship will the young males be expected to shoulder its duties.

The more closely knit an animal society is, and the more interdependent its members, the higher the rate of taxation. Among bell miner birds of Australia, for example, pairs of breeding adults are assisted at the nest by several youthful helpers, usually male. The helpers provision the couple's fledglings with a steady supply of lerp, sugary casings secreted by plant-sucking insects. And though some scientists had wondered whether lerp wasn't basically a junk food, offered up to the young bell miners as much for show as for substance, researchers report in the March issue of Animal Behaviour that lerp is, in fact, as important to the fledglings' growth as is the meatier arthropod prey supplied by their parents. By all evidence, the helper birds are honestly "paying to stay," trading a valuable currency for the right to remain within the aggressively guarded precincts of a bell miner breeding colony, with the hope of better times and personal propagation opportunities ahead.

Or at least of averting personal injury. Among another Australian species of cooperatively breeding birds, the superb fairy-wren, dominant males notice when their helpers are less than superb about paying their taxes. Should a helper fail to feed and groom the dominant's nestlings, or to give an alarm call on seeing intruders enter the territory, the dominant male will angrily chase, harass and peck at the helper, for up to 26 hours at a time. In the case of the highly social cichlid fish, fear of punishment inspires delinquent helper fish to ostentatiously redouble their contributions to the communal nest, their digging in the sand, their cleaning and fanning of the eggs - rather like politicians who suddenly pony up three years of back taxes for themselves, the nanny and the gardener. "If they don't pay their bill, there will be punishment," said Michael Taborsky of the University of Bern, "so they try to pre-emptively appease the dominant individuals in the group."

If hope and fear don't guarantee compliance, there's always embarrassment. Vampire bats are famous for their willingness to regurgitate a blood meal to feed fellow bats that are down on their luck. In fact, hiding one's wealth is a problem. A fully fed vampire bat is as bloated as a fraternity water balloon, and the bats appear to rub bellies to see who is in a position to share. "It's hard to cheat when your stomach is obviously distended," Dr. Santos said.

It's also hard to cheat when you live in a small band of big-brained, sharp-eyed individuals, as humans did for vast stretches of our past, which may help explain why we are so easily taxed. "There's not a human society in the world that doesn't redistribute food to nonrelatives," said Samuel Bowles, director of the behavioral sciences program at the Santa Fe Institute. "Whether it's through the state, or the chief, or a rural collective, or some other mechanism, food sharing of large nutritional packages is quite extensive and has been going on for at least 100,000 years of human history." In hunting and foraging cultures, the proportional tax rate is so high, said Dr. Bowles, that "even the Swedes would be impressed."

Take the case of the Ache tribe of Paraguay. Hunters bring their bounty back to a common pot. "The majority of calories are redistributed," he said. "It ends up being something like a 60 percent income tax."

Pastoral and herding societies tend to be less egalitarian than foraging cultures, and yet, here, too, taxing is often used to help rectify extreme inequities. When a rich cattle farmer dies among the Tandroy of southern Madagascar, Dr. Bowles said, "The rich person's stock is killed and eaten by everyone," often down to the last head of cattle. "That's a 100 percent inheritance tax."

Modern taxes are just a "newfangled version of commitment to the group," said David Sloan Wilson of Binghamton University, the result of the invention of money. Yet even with our elaborate, abstracted tax code, fear of public opprobrium remains an impressive motivator. "It's expected that powerful, high-status members of society should be contributing more," Dr. Wilson said. "If they don't, they won't remain high status for long." And for the fat bats among us who just won't cough up the goods - there's always jail.