Elephant hunt: how many species are there? (Science News).

From a distance, scientist Lori Eggert spies on a West African elephant herd. She watches patiently until, finally, something plops from an animal's rear: "That's what we're looking for," she says, and moves in to scoop up a forkful of dung. Believe it or not, fresh dung may help Eggert and her colleagues at the University of California at San Diego prove the existence of an entirely new elephant species. And if Eggert is right, her findings could help save this species of the world's largest land animal from extinction.

Until recently, all African elephants were classified as one of two species: stocky straight-tusked forest elephants (Loxodonta cyclotis), or towering bow-tusked savannah beasts (L. africana). But appearance alone doesn't distinguish one species from another. In fact, some of Eggert's newly identified elephants--which roam the West African savannah--sport savannahlike tusks; others resemble forest elephants.

How can Eggert tell if her finds are unique? From their dung she extracts microscopic DNA, hereditary information stored in each of a species' billions of cells. Typically, DNA is collected from blood samples--but stabbing a needle into a 6 ton (13,000 pound) elephant is a gamble with death: The animal can be sedated, but if the woozy giant should fall onto its chest, it can suffocate under its own weight--or crush a scientist!

When Eggert compared hundreds of DNA samples, she found the genes (hereditary units stored on DNA) of savannah and forest specimens to be different from the genes of West African elephants--which could mean they're Africa's third species.

Eggert thinks the elephants' speciation (separation into a new species) began more than 2 million years ago, when West African elephants migrated away from central and southern African relatives. As the population became more isolated, it developed unique genetic characteristics to adapt to its new environment.

If accurate, her discovery comes just in time. Until now, scientists clumped West African elephants with forest and savannah populations. But out of the estimated 500,000 elephants living in Africa, only about 12,000 are West African. Their numbers are shrinking as humans invade elephant habitats. If scientists relied only on appearances, the West African elephants might have gone extinct before anyone realized it. Now conservationists can protect the animals by urging governments to stop land development. Says Eggert, "Genetics is helping us understand the species and habitats we most need to preserve."

HEAVY FACTS ON ELEPHANTS

* An elephant's trunk is powerful enough to kill a lion with one swipe.

* An average elephant tongue weighs 12 kg (26 lb).

* Elephants can communicate over a distance of 50 km (30 mi) by making a low rumbling sound through their trunks.