Dodos might have been quite intelligent, new study finds

February 23, 2016
A model of a dodo that will be on display in the American Museum of Natural History's upcoming exhibition about the relationships between birds and dinosaurs, Dinosaurs Among Us. Credit: © AMNH/C. Chesek

New research suggests that the dodo, an extinct bird whose name has entered popular culture as a symbol of stupidity, was actually fairly smart. The work, published today in the Zoological Journal of the Linnean Society, finds that the overall size of the dodo's brain in relation to its body size was on par with its closest living relatives: pigeons—birds whose ability to be trained implies a moderate level of intelligence. The researchers also discovered that the dodo had an enlarged olfactory bulb—the part of the brain responsible for smelling—an uncharacteristic trait for birds, which usually concentrate their brainpower into eyesight.

The dodo (Raphus cucullatus) was a large, flightless bird that lived on the island of Mauritius in the Indian Ocean. They were last seen in 1662.

"When the island was discovered in the late 1500s, the dodos living there had no fear of humans and they were herded onto boats and used as fresh meat for sailors," said Eugenia Gold, the lead author of the paper, a research associate and recent graduate of the American Museum of Natural History's Richard Gilder Graduate School, and an instructor in the Department of Anatomical Sciences at Stony Brook University. "Because of that behavior and invasive species that were introduced to the island, they disappeared in less than 100 years after humans arrived. Today, they are almost exclusively known for becoming extinct, and I think that's why we've given them this reputation of being dumb."

Even though the birds have become an example of oddity, obsolescence, stupidity, and extinction, and have been featured in popular stories ranging from Alice in Wonderland to Ice Age, most aspects of the dodo's biology are still unknown. This is partly because dodo specimens are extremely rare, having disappeared during the nascent stage of collections.

Side views of brain endocasts from the dodo (A), the Rodrigues solitaire (B), and Caloenas nicobarica (C), a type of pigeon. Enlarged olfactory bulbs, labeled "ob," can be seen in the dodo and the solitaire. The scale bar is 15 millimeters. Credit: © AMNH/E. Gold

To examine the brain of the dodo, Gold tracked down a well-preserved skull from the collections of the Natural History Museum, London, and imaged it there with high-resolution computed tomography (CT) scanning. In the American Museum of Natural History's Microscopy and Imaging Facility, she also CT-scanned the skulls of seven species of pigeons—ranging from the common pigeon found on city streets, Columba livia, to more exotic varieties. Out of these scans, Gold built virtual brain endocasts to determine the overall as well as the size of various structures. Gold's colleagues at the Natural History Museum of Denmark and National Museum of Scotland sent her the endocast for the dodo's closest relative, the extinct island-dwelling bird Rodrigues solitaire (Pezophaps solitaria).

When comparing the size of the birds' brains to their body sizes, Gold and collaborators found that the dodo was "right on the line."

"It's not impressively large or impressively small—it's exactly the size you would predict it to be for its ," Gold said. "So if you take brain size as a proxy for intelligence, dodos probably had a similar intelligence level to pigeons. Of course, there's more to intelligence than just overall brain size, but this gives us a basic measure."

The study also revealed that both the dodo and the Rodrigues solitaire, which recently was driven to extinction by human activity, had large and differentiated olfactory bulbs. In general, birds depend much more on sight rather than smell to navigate through their world, and as a result, they tend to have larger optic lobes than olfactory bulbs. The authors suggest that, because dodos and solitaires were ground-dwellers, they relied on smell to find food, which might have included fruit, small land vertebrates, and marine animals like shellfish.

"It is really amazing what new technologies can bring to old museum specimens," said co-author Mark Norell, Macaulay Curator of Paleontology and Chair of the Division of Paleontology at the American Museum of Natural History. "This really underscores the need for the maintenance and growth of natural history collections, because who knows what's next."

The researchers also discovered an unusual curvature of the 's semicircular canal—the balance organs located in the ear. But as of yet, there's not a good hypothesis for this atypical feature.

Explore further: New insights into an old bird

More information: Zoological Journal of the Linnean Society: onlinelibrary.wiley.com/doi/10 … 1/zoj.12388/abstract

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ralbol
4 / 5 (8) Feb 23, 2016
Now, we need a study to prove, once and for all, that this other creature, you know, the one that contaminates its water and air, the one that soils its environment, the one that kills its own kind, you know the one... what's the name I'm looking for.... Ah ! Yes ! The Human beast ! We need a serious study that proves without a doubt that this animal is the stupidest, the dumbest creature that walked the surface of the Earth.

Shouldn't be too difficult a study to make.
chileastro
3 / 5 (8) Feb 23, 2016
Would you determine the intelligence of bison and its wild cousins based on a domesticated cow? Use commercial pigs as a proxy for wild boars? Of course not. We all know that the domesticated version is not so nearly intelligent as it was before domestication. Ditto humans. Religion is the factory farming of humans and after thousands of years of domestication you are commenting on the predictable result.

Religion started at about the same time as agriculture and domestication of livestock. That's not a coincidence. Some bright philosopher/king thought "why not manage everything that way" and you have the birth of religion as the factory farming of humans and a best practice for the state's control of behavior.
antigoresockpuppet
1 / 5 (5) Feb 23, 2016
CA's theory would at least explain why religion can claim to be bankrupt, care little for suffering around the world, but talk about ANY societal acceptance of anything but breed, breed, breed and they're all motivated. Gay marriage is total anathema. The farmer don't like that one bit.

How can Francis call for environmental stewardship and working against AGW, whilst damned to hell anyone that uses a condom??? It demonstrates that even when they get the picture they can't act against their core principle. There's nothing that reduces footprint like reducing feet on the ground. Do the maths. One person living a pretty normal life produces less waste than a family of four that is ultra-green.

This is where AGW is a total hoax and distraction. It doesn't matter if it's true or not, it's still being used as a distraction. *Most* the threatened environment would be *just* as bad off without AGW due to human population growth.
promile
Feb 23, 2016
This comment has been removed by a moderator.
antigoracle
1 / 5 (4) Feb 23, 2016
Now, we need a study to prove, once and for all, that this other creature, you know, the one that contaminates its water and air, the one that soils its environment, the one that kills its own kind, you know the one... what's the name I'm looking for.... Ah ! Yes ! The Human beast ! We need a serious study that proves without a doubt that this animal is the stupidest, the dumbest creature that walked the surface of the Earth.

Shouldn't be too difficult a study to make.

Yep. You are proof.
Osiris1
5 / 5 (1) Feb 25, 2016
Damn, the ancient ancestor of Donald Trump
ralbol
5 / 5 (1) Feb 25, 2016
antigoracle

Let me guess... you're a republican...

So obvious !
Whydening Gyre
5 / 5 (2) Feb 25, 2016
hmm. 7 comments on an article about an extinct bird - and not one of them about the article...
Captain Stumpy
5 / 5 (3) Feb 25, 2016
...and not one of them about the article...
likely because of the apathy most hold towards its extinction, and the misconceptions around it (mistaking the lack of fear and their social hierarchy for being dumb, etc)
the most important part of the article
"It is really amazing what new technologies can bring to old museum specimens," said co-author Mark Norell... "This really underscores the need for the maintenance and growth of natural history collections, because who knows what's next."
i hope we do more investigations on old stuff with the new tech we have, personally... find new stuff
The researchers also discovered an unusual curvature of the dodo's semicircular canal—the balance organs located in the ear. But as of yet, there's not a good hypothesis for this atypical feature
i await these findings with excitement

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