The Smart, Agile, and Completely Underrated Dodo
Legends about the extinct bird being slow of foot and mind are just that: legends.
The dodo was a sitting duck. The bird was fat and flightless, clueless and clumsy. It was a walking evolutionary error practically preordained to die out. When the Dutch colonized the dodo’s small island home at the end of the 16th century, the earthbound oddity toddled straight into the waiting arms of hungry sailors and settlers.
Less than 100 years later, it was extinct.
At least, that’s how the story usually goes. There’s just one small problem with this shopworn extinction tale: It’s almost entirely false. Over the last several years, anatomical and ecological studies have shed new light on the dodo and its history, redeeming the bird’s dismal reputation.
“The dodo’s always been considered to be a comical animal … so ludicrous that it was destined to become extinct, which is absolutely not the case,” says Julian Hume, an avian paleontologist at the Natural History Museum in London. “This bird was perfectly adapted to its environment.”
The origins of the dodo, which belongs to the pigeon family, remain something of a mystery. Approximately 8 million years ago, the small volcanic island of Mauritius formed in the Indian Ocean. Not long thereafter, scientists believe, the dodo’s ancestors arrived on the island, eventually evolving into giants and losing their ability to fly. The first published record of the bird dates to 1599, a year after the Dutch claimed Mauritius, turning the island into a port of call and, later, a settlement. Sometime during the second half of the 17th century—the exact date is unknown—the last dodo took its last breath.
At the time, the concept of extinction—the notion that an entire species could vanish with no possibility of return—had not yet been developed, nor had advanced taxidermy techniques, and few good dodo specimens survived. The scarcity of physical evidence, combined with unreliable descriptions and fanciful illustrations of the birds, allowed myths and misconceptions to take root.
“Even though the dodo is so well known in popular culture, scientifically actually it was much more of a wasteland,” says Leon Claessens, a paleontologist at College of the Holy Cross. A major Mauritian fossil deposit, discovered in 1865, has now yielded numerous individual bones, but there’s only one known skeleton comprised entirely of the bones of a single dodo. A Mauritian barber and amateur naturalist named Louis Etienne Thirioux found the skeleton in the early 20th century, but the specimen, currently housed by the Mauritius Institute in Port Louis, Mauritius, received little scientific scrutiny.
In 2011, Claessens and two of his students travelled to Mauritius to take a closer look at Thirioux’s find. They used a 3-D laser scanner to produce high-resolution images of each bone, later reassembling these images into a three-dimensional, digital model of the skeleton. (The team also scanned and modeled a second skeleton discovered by Thirioux, which is composed of the bones of at least two different dodos.)
Claessens and two other paleontologists—Hume and Hanneke Meijer, a paleontologist at the University Museum of Bergen in Norway—then studied the bones in detail, making a number of novel observations about the dodo’s anatomy and inferences about how it moved. (Their findings were published in a special issue of the Journal of Vertebrate Paleontology in March.) The dodo, they observed, was a sturdy, robust bird, with thick leg bones and a broad pelvis. It also had sizable kneecaps, which scientists had never noted before and would have given the heavy, flightless bird knee joints that were “maneuverable, strong, and supportive,” Hume says. “This would be ideal for the dodo to move quickly in its rocky, densely forested home.”
Numerous previous studies have suggested that dodos were not nearly as fat as they looked in historical illustrations, and the new digital reconstruction reveals a bird with a more upright posture and slimmer ribcage than commonly depicted. These findings, combined with the bird’s pelvic shape and the positioning of its hip joints, indicate that the dodo could have moved swiftly and efficiently on the ground. Indeed, it was probably quite agile. “It has a very underserved reputation of this clumsy, kind of lumbering, inadequate bird, almost like a soccer ball with some legs under it,” Claessens says. “Even though it’s not going to be the Usain Bolt of the animal or the bird kingdom, it has an anatomy that is consistent with much greater agility.” In fact, one 17th century sailor reported that dodos were so speedy that they could be hard to catch.
When Claessens and his team examined the dodo’s wings, they found pronounced bumps, ridges, and depressions where the muscles would have attached to the bones. These well-defined muscle impressions suggest that the dodo’s wings were not withered, worthless appendages but in active use. One possibility is that the birds used their wings for balance, especially when moving quickly. “It's like walking a tightrope—being able to flutter these wings, being able to stretch them out, gives you some capacity for improved balance,” Claessens says.
While Claessens and his colleagues were analyzing the dodo’s skeleton, another group of scientists was trying to make sense of the dodo mind. The research team, based at the American Museum of Natural History, used CT scans of a dodo skull to create virtual, three-dimensional models of the extinct bird’s brain. The scientists also created similar brain models for eight closely related species, including several types of modern pigeons and the Rodrigues solitaire, another extinct flightless bird that lived on an island near Mauritius. The dodo and the solitaire, the researchers reported in February, both had enlarged olfactory bulbs, which is unusual for birds. The finding suggests that the dodo may have had an enhanced sense of smell, an adaptation that could have helped it sniff out ripe fruit and other food in the island’s thick vegetation.
The dodo’s brain was of completely average size; the ratio of its brain volume to its total body mass was similar to that of modern pigeons, highly trainable birds with a talent for visual discrimination and navigation. “Because the dodo's brain volume is completely proportional to its body size, we made the jump to say that it's probably not super dumb, which is what the legends say about dodos,” says Eugenia Gold, the study’s lead author. Of course, she acknowledges, brain size isn’t a perfect proxy for intelligence. “So that's a big caveat of our study, but when you can't observe the bird directly because it's extinct, brain volume gives you at least one metric to sort of get a handle on this,” she says. (The dodo is not the only extinct species we’ve underestimated; scientific evidence indicates that Neanderthals—commonly depicted as dumb, lumbering brutes—engaged in a variety of sophisticated behaviors, including tool making and cave painting.)
Further insights are emerging from the work of paleoecologists and geologists, who have been reconstructing the dodo’s island habitat. For much of its history, Mauritius would have been a tough and turbulent place for wild animals to live. It was volcanically active and regularly struck by cyclones, which could cause severe food shortages. Extreme climatic shifts led to long periods of severe drought, fueling wildfires and mass animal die-offs. When one such megadrought struck 4,200 years ago, a shallow freshwater lake in island’s Mare aux Songes region began drying up. As thirsty animals crowded around the shrinking water surface, they left nutrient-rich droppings that fed the growth of toxic bacteria. Many thousands of animals, from at least 22 different species, perished as the lake transformed into a muddy, poisonous swamp. “We are not sure if animals died there because they drank the water and then subsequently died of this toxic cyanobacteria or if they died because they couldn’t drink enough,” says Erik de Boer, a paleoecologist at the University of Amsterdam who authored a 2015 paper on the die-off. (Some critters likely also simply got mired in the muck.)
Though many dodos died at Mare aux Songes—indeed, the swamp is a major source of preserved dodo bones—the species soldiered on. “The dodo was a survivor in that respect,” says Kenneth Rijsdijk, a physical geographer at the University of Amsterdam who collaborated on the 2015 study and has been studying the Mare aux Songes site for a decade. In fact, Rijsdijk points out, the dodo’s multi-million-year tenure on the planet far exceeds our own, which stretches back just 200,000 years or so. (Dinosaurs, another icon of extinction and obsolescence, had a reign of some 160 million years.)
Although the exact causes of the dodo’s demise are unclear, there's little evidence that they were hunted to extinction. Excavations of Fort Frederik Hendrik, which housed Dutch settlers between 1638 and 1710, suggests that the settlers fed mainly on livestock they brought to the island, as well as local fish. The animal remains unearthed there have not included a single dodo bone. Journals from Dutch sailors do reveal that dodos were eaten at least occasionally, but Rijsdijk and Hume say it’s unlikely that the relatively small group of colonists on the island—250 people at the peak and often far fewer—could have devoured all of them, especially given the thickness of the island’s forests and the difficulty of its terrain.
But humans aren’t exactly off the hook; we likely caused the dodo’s extinction indirectly, by introducing a variety of non-native species, including pigs, goats, deer, monkeys, and rats. Some of these creatures, particularly pigs, would have eaten dodo eggs and chicks, while others competed with dodos for food. “When you come and pull the rug out from underneath an ecosystem in such a short time as what happened when humans arrived on Mauritius, there’s just no capacity for any species to react,” Claessens says. But that doesn’t mean the dodo was inept, maladapted, or “an evolutionary loser,” he says. “There’s no such thing.”
Evolution is not some inexorable march toward progress and extinction is not a value judgment. Animals—even strong, fast, intelligent animals—die out for all sorts of reasons, killed off by climate change, or habitat destruction, or human exploitation, or just an asteroid-sized bit of bad luck. Statistically, it's almost guaranteed; scientists have estimated that more than 99 percent of all the species that have ever existed on the planet are now extinct. For millennia, the dodo was a survivor, resilient in the face of extreme environmental challenges. And then, in a flash, it was gone.