Cannibalism seems a quaint, titillating subject where we usually encounter it, in anthropological studies and spooky legends. Dale Peterson's ugly, important new book is essentially about cannibalism as construed more broadly than usual, and in his treatment it's anything but quaint. Picture a gorilla killed with a shotgun, butchered like a hog, its blood-dripping head tossed into a stewpot, its hands smoked like sausage, and you have the idea. That gorilla is no metaphor. ''Eating Apes'' is an examination of the slaughter, for food, of humanity's four closest primate relatives.  It happens in equatorial Africa, notably those countries (Cameroon, Gabon, and both Congos, among others) where chimpanzees, bonobos (also known as pygmy chimps) and gorillas (now divided into two species by some experts) live in the wild but often find their way, dead, into meat markets, even restaurants. They are typically killed with a 12-gauge shotgun firing big-game cartridges, each cartridge containing nine heavy balls of buckshot. Joseph Melloh, a reformed Cameroonian poacher who at one time was shooting about 50 gorillas a year for the market, has testified that gorilla meat is ''sweet, very sweet.'' Each carcass was worth up to 30,000 Central African francs, roughly $50.  Ape-eating may sound unambiguously loathsome to us, but it's part of a larger and more complicated regional context. In the Lingala language of central Africa, a trading tongue that spans ethnic divisions, the word eyama means both wild animal and meat. Likewise, as Peterson tells us, the Hausa language of Nigeria and the Swahili of eastern Africa have their variants of the same term (nama, nyama), each connoting both flesh in the forest and flesh in the pot.  The linguistic overlap reflects old traditions among hunting-based cultures, to which the notion of domestic livestock, raised for food and distinct from what runs free on the landscape, was alien. In towns adjacent to the remaining forests of central Africa, even in capital cities of the region, those traditions remain strong. People eat wild meat when they must (for lack of alternatives) and when they can (preferring it to beef, poultry or pork).  The trade is huge, amounting to more than five million tons of antelope, elephant, buffalo, bush pig, porcupine, rodent, monkey and other native animals per year. Conservationists, concerned that African forests are being emptied of wildlife even faster than they're being cut for timber, refer to this as the problem of bushmeat. For other folks it's just a fact of existence. Life is harsh, tastes vary and wildlife is edible. Anyone who has enjoyed venison, a barbecued elk steak or a poached filet of king salmon caught from the wild is in no position to consider bushmeat unreasonable in principle.  But there are reasonable limits. One is what forest ecosystems can sustain. Given recent increases in population, bushmeat demand, availability of guns and ease of transport, those ecosystems generally can't sustain current levels of kill. Although dead apes may account for only 1 percent of the bushmeat trade in the Congo basin, that toll combined with continuing habitat destruction pushes chimpanzees, bonobos and gorillas ever closer to extinction. Apes reproduce slowly, and their populations are already sorely reduced. Of the eastern gorilla (which includes the mountain gorilla subspecies), no more than about 17,500 individuals remain -- possibly far fewer, given that an indeterminate number have been killed in recent years to feed miners in the eastern Democratic Republic of Congo.  Another limit is taxonomic. Eating apes, Peterson argues, is uniquely destructive and unacceptable ''because of who they are. They are our sibling species, who share with us between 96 and 99 percent of their genetic code.'' Apes are ''special beings,'' he adds, ''who observe the world through eyes and faces like ours,'' show similar emotions, live in similar social systems and display traces of humanlike intelligence, language skills, and humor. ''Killing and eating them amounts to killing and eating animals shockingly close to human.''  Karl Ammann's lurid photos make the same point more bluntly. A severed gorilla head, on a kitchen counter, wears the sad, glazed expression of a betrayed friend. What looks at first like a leather driving glove, on a table amid beer bottles, is a severed gorilla hand. The juxtapositions may seem stagy, but the reality behind them is raw and unanswerable.  A third argument against eating apes, if you need another, is medical and epidemiological. In a morbidly fascinating chapter titled ''Blood,'' Peterson describes the scientific work and circumstantial evidence suggesting that both AIDS and Ebola are zoonotic diseases (that is, transmissible to us from animals), which have leaped from ape populations to humans on several occasions, most likely during the butchery and consumption of hominoid bushmeat.  The linkage of H.I.V. to simian immunodeficiency virus (S.I.V.) in West African chimps has been presented in journals like Nature. The case for Ebola is more speculative, but Peterson recounts the story of a village called Mayibout 2, on the Ivindo River in eastern Gabon, where a chimp found dead in the forest was butchered, cooked and eaten, leading to an Ebola outbreak in which 21 people died. I heard tales of Mayibout 2 myself, when I traveled in that area, including one from a survivor who remembered not just the infectious chimp but also a pile of 13 dead gorillas in the forest nearby, all killed by some mysterious agent other than a shotgun. No one yet knows what species (a rodent? a bat?) serves as the permanent reservoir of the Ebola virus, but patterns of gorilla and chimpanzee die-off suggest that our close relatives are capable of suffering from it and passing it along.
The chances of keeping Africans from eating all their apes don't look good, says Dale Peterson in an ugly, important new book.