Q) Do any cannibalistic societies exist today?
Craig Collins, Santa Rosa, California
A) THE TWO TRIBES known to have practiced cannibalism most recently are the Fore of Papua New Guinea and the Wari of western Brazil, both of which had given up eating people by the 1960s, at the urging of colonizers. "The Wari ate their enemies after warfare as a way of expressing anger and disdain for them," says Vanderbilt anthropology professor Beth Conklin, who lived with the Wari in the 1980s and interviewed many onetime cannibals. "They also consumed members of their own group who died naturally, out of respect." Anthropologists aren't aware of any cannibalism occurring todaybut a lot depends on your definition of the term. The Yanomami of the Amazon, for example, still practice osteophagy, the consuming of the ground bones of one's relatives after cremation as a symbol of affection, or as a way of invoking the ancestor's spirit before going into battle to avenge his death. "When you study its various uses, you realize that cannibalism isn't as disgusting as you originally thought," says Conklin. Stop right there, professor. You're beginning to scare us.
Q) How accurately north is the North Star? Who first noted its northness?
Michael Dunn, Nashua, New Hampshire
A) POLARIS, which is known to modern-day earthlings as the North Star, is off true north by only three-quarters of one degree. But it hasn't always been the North Star. That's because the earth, experiencing the gravitational tug of the sun and the moon, wobbles slightly on its axis of rotation. If you extended the earth's axis into space, the wobbling would cause the axis to draw a circle at the opposite end of the sky, with a diameter of about 47 degrees, once every 26,000 years. So while our planet's northern axis currently points toward Polaris, if you rewind or fast-forward 13,000 years, it will point to another major star, Vega. (By contrast, the sky above our southern axis is devoid of bright objects, which is why there is no South Star.) As for someone "discovering" the North Star, according to Bruce Koehn, a research scientist at Arizona's Lowell Observatory, "that's like saying someone discovered that the sky is blue." Whichever North Star you're referring to, says Koehn, "people have almost certainly used it for navigation since prehistory."
Q) If the purpose of berries is to be eaten by animals, which then scatter the seeds so the plant can reproduce, then why are there poisonous berries?
Rosalie Potts, Wayne, Maine
A) THE ASSUMPTION here is that berries exist to be eaten by animals and dispersed in their poop. Unfortunately, this is flawed on two counts. First off, the chief purpose of berries, like all fruit, is to protect the seedthink of them as nature's bubble wrapuntil the plant is ready to propagate new seedlings. Second, the seeds that get eaten are quite often digested, not excreted, which can spell reproductive trouble for the unlucky plant. "It's spending all its energy making seeds but isn't getting the return on its investment because its seeds are being gobbled up," says Kristina Schierenbeck, an evolutionary botanist at California State University at Chico. That's when the species needs to try another evolutionary strategy. It could develop a seed with a protective coating, which can pass through an animal's system and survive to germinate elsewhere, or it might lace its berries with poison. Animals will either snack on them and die, she says, orlike the bird that wisely spits out the toxic seeds when eating the fruit from a yew plantlearn a healthier behavior. Mind you, the same plants are not poisonous to all animals, which complicates matters. So just because you see a rabbit gorging itself on death-cap mushroomsAmanita phalloidesdon't assume you can do the same. Then again, the words "death cap" probably tipped you off to that.