The first extensive skull analysis of the ill-fated dodo bird has concluded that a creature long labeled as stupid actually may have been quite intelligent — yet too trusting of the humans who drove them into extinction.
For speakers of English, the word dodo has never been a compliment, and in popular culture is synonymous with a host of other pejoratives for low intelligence — dumb, dunce, dullard. And despite being smeared as one of the dumbest animals ever to draw breath, no one in more than three centuries has even seen one of the flightless birds. The last recorded dodo sighting was in 1662.
But Eugenia Gold, an anatomical sciences instructor at Stony Brook University School of Medicine, wound up breaking new scientific ground when she undertook a study of the bird.
The moonlighting paleontologist identified an intact skull at the Museum of Natural History in London and put it to a series of tests, including X-ray examination.
During the course of her research Gold uncovered information about the creature’s brain, and hence its intelligence, that essentially reverses 354 years of character assassination.
“I didn’t go into this with the assumption of finding anything related to intelligence at all,” Gold said, explaining that she studied the dodo head using a high-resolution CT scanner and examined the cranial vault, the space where the brain resides in living animals. Gold also conducted a statistical analysis to further tease secrets from the ancient bird.
“When I did the regression [analysis] of brain size versus body size, using brain size as a proxy for intelligence, it became apparent that [the dodo] was probably as intelligent as modern pigeons,” said Gold, who also digitized the skull and compared it with pigeons.
Pigeons are not only relatives of the dodo, they are smart enough to be trained, a sign of intelligence, Gold said.
Research outside of hers has found that homing pigeons possess an inborn GPS system allowing travel over great distances, then finding their way home again. Pigeons use magnetoreception, which allows them to detect a magnetic field and select altitude and navigate the skies.
Although they were flightless, Gold found dodos had their own inborn system that greatly aided survival.
“The dodo and its closest relative, the Rodrigues solitaire, both had large olfactory bulbs,” Gold said of a brain structure that not only allowed a keen sense of smell but, because of its size, enhanced it.
The large olfactory bulb was unusual because birds rarely rely on a sense of smell because of their keen eyesight, crucially needed while in flight, Gold said.
“We think the dodo and the solitaire were using their sense of smell to sniff out fruit that might be buried in dirt or sand. They were not on the wing like other birds that could actually look for food.”
Dodos lived only on the island of Mauritius in the Indian Ocean and were driven to extinction by sailors who corralled the birds onto ships then dined on them during voyages, Gold said.
“Since they were ground dwellers they really didn’t have a chance,” she added.
Paul Sweet, manager of the ornithology collection at the American Museum of Natural History in Manhattan, applauded Gold’s research, which is reported in the current issue of the Zoological Journal of the Linnean Society.
“Everything we can learn about extinct birds is important,” Sweet said. “Dodos were very enigmatic. But they were intelligent just like pigeons. I am sure they were well-adapted on Mauritius until humans came along and killed them.
“In that period of European expansion we lost a lot of animals,” Sweet added. “If you could boil it and eat it, that’s what happened. For dodos, there was nowhere to escape, nowhere to hide.”