Laser scans of complete Dodo skeleton reveal a little-known bird not doomed to extinction

11/6/2014 | 0

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Andrew Biedlingmaier, a student at the College of the Holy Cross, makes a 3-D scan of the only complete Dodo skeleton at the Natural History Museum of Mauritius. Image courtesy of Leon Claessens and the Mauritius Museums Council

In the world’s lexicon, the Dodo is an example of clumsiness, a species doomed to go extinct.

Such perceptions, say an international team of researchers, are mostly wrong.

In fact, the Dodo, which went extinct on the island of Mauritius 320 years ago, was a member of the pigeon family, one that found a niche on an island free of mammalian predators. What’s more, the story of the bird’s demise sheds much-needed light on the processes by which species are disappearing today.

The 3-D scan of the Thirioux Dodo skeleton. Image courtesy of Leon Claessens and the Mauritius Museums Council

The 3-D scan of the Thirioux Dodo skeleton. Image courtesy of Leon Claessens and the Mauritius Museums Council

The researchers — Leon Claessens of the College of the Holy Cross in Massachusetts, Julian Hume of the Natural History Museum UK, Hanneke Meijer of the Institut Català de Paleontologia in Barcelona, and their colleagues in the Dodo Research Programme — recently reconstructed how the Dodo walked, moved, and lived in unprecedented detail. They did so with the help of a high-tech 3-D laser scanner, which they used to study the only known complete skeleton.

An amateur collector found the bones around 1903 on Mauritius. “Being able to examine the skeleton of a single individual Dodo, which is not made up of as many individual birds as there are bones, as is the case in composite skeletons, truly allows us to appreciate the way the Dodo looked and see how tall or rotund it really was,” says Hume.

The Thirioux skeleton, named for its discoverer, Etienne Thirioux, contains “even the smallest bones, such as the kneecaps, that are usually lost when an animal disintegrates,” says Claessens. “Several of those bones were previously unknown and have never been described scientifically.”

Seeing the Dodo as it actually was, the researchers say, provides a rare glimpse into the process of animal extinction. “If we want to understand the effects of ecosystem disruption in order to aid conservation, then in-depth knowledge of previous extinction events is paramount.”

The Edwards' Dodo, one of the most famous and often-copied paintings of a Dodo specimen, was painted by Roelant Savery in 1626. It is housed at London’s Natural History Museum. Licensed under public domain via Wikimedia Commons

The Edwards’ Dodo, one of the most famous and often-copied paintings of a Dodo specimen, was painted by Roelant Savery in 1626. It is housed at London’s Natural History Museum. Licensed under public domain via Wikimedia Commons

Using scans of the skeleton, Claessens, Meijer, and their colleagues estimated the Dodo’s weight. Skinny birds had a mass of 25 pounds (11.3 kg), intermediate birds weighed about 32 pounds (14.5 kg), and fat Dodos could have topped the scales at 42 pounds (19 kg), they say.

If the species had lived, it would be among the heaviest birds on the planet, weighing about the same as the King Penguin.

“The Dodo was indeed a large and heavy bird,” say Claessens and Meijer. “This was due to the absence of predators on Mauritius; the Dodo’s ancestors no longer needed to fly to escape predators. Thus over time, the bird’s wings decreased in size and its body size increased. Surprisingly, we know very little about what the Dodo ate and how much it had to eat daily. Historical accounts indicate that the Dodo ate fruits and seeds, much like modern-day pigeons.”

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Painting of a Dodo head by Cornelis Saftleven from 1638. It may be one of the last illustrations made of a live Dodo. The work is housed at Boijmans Museum in Rotterdam. Licensed under public domain via Wikimedia Commons

In 2005, scientists uncovered a fossil deposit in southeast Mauritius that contained the bones of thousands of animals. Long ago, the site was the home of a freshwater lake, but when an extreme drought struck Mauritius 4,200 years ago, the lake shrank, salinization occurred, bacteria bloomed, and the water was poisoned. Flightless birds, giant tortoises, and other animals became stuck and died, leaving behind a remarkable fossil record of the consequences of a changing climate.

At the site, known as Mare aux Songes, the researchers found the bones of 24 bird species (Dodos, pigeons, parrots, and small songbirds), 15 reptiles (skinks, giant tortoises), and five mammals (all bats).

Despite the drought, all of the species survived, and when Europeans arrived on Mauritius in the 1500s, the animals were still present. Now, many are extinct. The Dodo died out by about 1690.

“It wasn’t until after the arrival of humans that endemic species went extinct,” say Claessens and Meijer. “This is remarkable because the Mauritian ecosystem had been able to withstand dramatic climatic fluctuations in the past, but in the face of humans, it surrendered.”

Claessens, Hume, and Meijer’s study is being described today in Berlin at the annual meeting of the Society of Vertebrate Paleontology; it’s one of six presentations about the Dodo at the conference. A book-length monograph about the research will be published in fall 2015. — Matt Mendenhall, Managing Editor