WASHINGTON — Dumbo may have a new cousin.
Researchers analyzing genes of African elephants found that the forest and grassland groups are different enough to be considered separate species, which means that three distinct species of elephants exist in the world. Science has long recognized the clear differences between the African and Asian elephants.
The genetic dissimilarity between the forest and the savanna elephants "is like the difference between the lion and the tiger. It is that large," said Jill Pecon-Slattery, a genetic researcher at the National Cancer Institute.
Pecon-Slattery and her co-authors of a study appearing Friday in the journal Science said that based on differences seen in genes collected from 195 African elephants and from seven Asian elephants it is clear that there "should be a species level recognition" for the two African groups.
The African elephant genetic samples were collected over eight years using darts fired into animals in 21 different groups. The darts were designed to punch and hold a small sample of skin from the target animals, then drop to the ground. When the elephants left, the researchers retrieved the darts and recovered bits of skin containing gene samples.
The technique was developed to enable researchers to trace the origins of illegal ivory.
A researcher in Africa, Nicholas Georgiadis of the Mpala Research Center in Kenya, directed the sample collection. The genetic study was conducted by Pecon-Slattery, Alfred Roca and Stephen O'Brien at the National Cancer Institute, one of the National Institutes of Health.
Naturalists have long noted the difference between the rarely seen forest elephant and the grassland, or savanna, elephant in Africa. The savanna elephant, known to scientists as Loxodonta africana, has large ears with ragged edges and curving tusks. It ranges widely in the grassland and bush country of east-central and southern Africa. This is the elephant most commonly seen in zoos.
The African forest elephant, known as Loxodonta cyclotis, is slightly smaller and has rounded ears. Its tusks are straighter and longer and the ivory has a slightly pink hue, making it highly prized.
Pecon-Slattery said enough genetic difference exists between the Asian and African elephants for them to be in different genera, which means they are more distantly related than are animals that share the same genus. Animals in the same genus can be closely related and still of different species.
The genetic difference between the forest and savanna African elephants is about 58 percent of the genetic difference between the African and Asian elephants, Pecon-Slattery said.
She said the two African elephant species are closely enough related that they could mate productively, and the study suggested there were hybrids of the two species in the distant past.
"It has occurred, but not that often," she said. "But this doesn't destroy the uniqueness of the original species."
Samuel Wasser, a conservation biologist at the University of Washington, said he and his colleagues have conducted an even more extensive genetic survey of the elephant, and their conclusion agrees that the African animals are of two distinct species.
Wasser, who has conducted extensive research in Tanzania, said the African elephant continues to be under intense poaching pressure. He said some studies have suggested the population has dropped from about 1.3 million the 1980s to about a half-million now.
The forest elephant is entering a new phase of poaching danger, Wasser said, because logging and road building have penetrated its dense jungle home and allow poachers easier access. Wasser said the illegal sale of the distinctive pink-hued ivory and meat from the forest elephant have both increased in recent years.
On the Net: Elephants: elephant.elehost.com/
Science: www.eurekalert.org