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Dodos Were Probably Pretty Smart, Study Finds

Because the dodo went extinct less than a century after humans first arrived on its native island of Mauritius, our knowledge of the large flightless bird is limited and comes almost exclusively from drawings and descriptions by sailors who saw it in the 17th century. Dodos had no instinctual fear of humans, who eventually hunted them into extinction, so they got a reputation for being dumb—the very embodiment of a creature destined for obsolescence.

But a new study suggests that the dodo was, in reality, fairly intelligent. Though collecting natural history specimens was not a popular pastime in the age of the dodo, scientists at the American Museum of Natural History and the Natural History Museum of Denmark managed to get ahold of one of the rare preserved dodo specimens—a skull housed in the collections of London’s Natural History Museum.

After scanning the skull, lead researcher Eugenia Gold created virtual endocasts—casts of the interior cavity of the skull showing impressions left by the brain. With these 3D models, she and her team were able to compare the dodo’s brain to those of several varieties of pigeons (the dodo’s closest living relative) and an extinct island bird known as the Rodrigues solitaire (its closest dead one). As they report in an article in the Zoological Journal of the Linnean Society, the dodo's brain was quite normal relative to its body size, indicating the bird wasn't particularly dim-witted.

Virtual endocasts of the dodo's brain

“It’s not impressively large or impressively small—it’s exactly the size you would predict it to be for its body size,” Gold explains in an AMNH press release. “So if you take brain size as a proxy for intelligence, dodos probably had a similar intelligence level to pigeons. There’s more to intelligence than just overall brain size, but this gives us a basic measure.” But if they were anything like pigeons, dodos were probably pretty clever. Though they’re more often thought of as urban pests, pigeons are able to distinguish between live and pre-recorded videos of themselves, and have been trained to serve as spies, couriers, and even cancer spotters

All images courtesy the American Museum of Natural History

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Animals
Goldfish Can Get Depressed, Too
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Don’t believe what Pixar is trying to sell you: Fish are not exactly brimming with personality. In aquariums, they tend to swim in circles, sucking up fragments of food and ducking around miniature treasure chests. To a layperson, fish don’t appear to possess concepts of happy, or sad, or anything in between—they just seem to exist.

This, researchers say, is not quite accurate. Speaking with The New York Times, Julian Pittman, a professor at the Department of Biological and Environmental Sciences at Troy University, says that fish not only suffer from depression, they can be easily diagnosed. Zebrafish dropped into a new tank who linger at the bottom are probably sad; those who enthusiastically explore the upper half are not.

In Pittman’s studies, fish depression can be induced by getting them “drunk” on ethanol, then cutting off the supply, resulting in withdrawal. These fish mope around the tank floor until they’re given antidepressants, at which point they begin happily swimming near the surface again.

It’s impossible to correlate fish depression with that of a human, but Pittman believes the symptoms in fish—losing interest in exploring and eating—makes them viable candidates for exploring neuroscience and perhaps drawing conclusions that will be beneficial in the land-dwelling population.

In the meantime, you can help ward off fish blues by keeping them busy—having obstacles to swim through and intriguing areas of a tank to explore. Just like humans, staying active and engaged can boost their mental health.

[h/t The New York Times]

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Pigeons Are Secretly Brilliant Birds That Understand Space and Time, Study Finds
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Of all the birds in the world, the pigeon draws the most ire. Despite their reputation as brainless “rats with wings,” though, they’re actually pretty brilliant (and beautiful) animals. A new study adds more evidence that the family of birds known as pigeons are some of the smartest birds around, as Quartz alerts us.

In addition to being able to distinguish English vocabulary from nonsense words, spot cancer, and tell a Monet from a Picasso, pigeons can understand abstract concepts like space and time, according to the new study published in Current Biology. Their brains just do it in a slightly different way than humans’ do.

Researchers at the University of Iowa set up an experiment where they showed pigeons a computer screen featuring a static horizontal line. The birds were supposed to evaluate the length of the line (either 6 centimeters or 24 centimeters) or the amount of time they saw it (either 2 or 8 seconds). The birds perceived "the longer lines to have longer duration, and lines longer in duration to also be longer in length," according to a press release. This suggests that the concepts are processed in the same region of the brain—as they are in the brains of humans and other primates.

But that abstract thinking doesn’t occur in the same way in bird brains as it does in ours. In humans, perceiving space and time is linked to a region of the brain called the parietal cortex, which the pigeon brains lack entirely. So their brains have to have some other way of processing the concepts.

The study didn’t determine how, exactly, pigeons achieve this cognitive feat, but it’s clear that some other aspect of the central nervous system must be controlling it. That also opens up the possibility that other non-mammal animals can perceive space and time, too, expanding how we think of other animals’ cognitive capabilities.

[h/t Quartz]

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