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Frogs Eat with Their Eyes—Literally

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When someone says people eat with their eyes, they usually mean that we assess and appreciate food by sight well before it ever hits our tongues. (What’s more, the appearance of food and even the container it’s in can actually change our perception of its taste.) If they’re talking about frogs, though, they mean it in a much different, more literal way. 

Scientists and nature lovers have often pointed out that frogs’ and toads’ eyes shut tight and sometimes seem to sink into their heads when they swallow food. This is because, scientists proposed, the amphibians’ eyes play a role in moving the food along. Specifically, they push food down the throat like a trash compactor. As biologist Mary Dickerson put it in 1906, “Strange as it may seem, the large eyes of the the toad can be pressed down into the mouth as far below its roof as they rise above the head, and the movement aids effectually in swallowing.” 

That does seem strange, but also really cool. The catch is that no one really tested the idea until 2004, when a team of biologists at the University of Massachusetts set out to see just what a leopard frog’s eyes are up to when it eats.

X-ray videos of the animals taken during meal time revealed that the eyes did move into the mouth, “came in contact with the prey and appeared to force it toward the pharynx.” Recordings of the electrical activity in the eye retractor muscles, meanwhile, showed that the eye retractions were active and on purpose, and that the eyes weren’t just sinking due to low pressure in the mouth below them during swallowing. Finally, an experiment where the researchers cut the nerves to the retractor muscles showed that frogs that couldn't retract their eyes were still able to swallow, but had to swallow almost twice as many times as usual to get each piece of food down. 

All this suggests, the researchers say, that frogs' eyes do help them swallow by aiding the tongue in pushing food into the throat, and probably contribute more to the process when their meals are larger. 

[h/t Io9]

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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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The Queen's Racing Pigeons Are in Danger, Due to an Increase in Peregrine Falcons
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Queen Elizabeth is famous for her love of corgis and horses, but her pet pigeons don't get as much press. The monarch owns nearly 200 racing pigeons, which she houses in a luxury loft at her country estate, Sandringham House, in Norfolk, England. But thanks to a recent boom in the region’s peregrine falcon population, the Queen’s swift birds may no longer be able to safely soar around the countryside, according to The Telegraph.

Once endangered, recent conservation efforts have boosted the peregrine falcon’s numbers. In certain parts of England, like Norfolk and the city of Salisbury in Wiltshire, the creatures can even find shelter inside boxes installed at local churches and cathedrals, which are designed to protect potential eggs.

There’s just one problem: Peregrine falcons are birds of prey, and local pigeon racers claim these nesting nooks are located along racing routes. Due to this unfortunate coincidence, some pigeons are failing to return to their owners.

Pigeon racing enthusiasts are upset, but Richard Salt of Salisbury Cathedral says it's simply a case of nature taking its course. "It's all just part of the natural process,” Salt told The Telegraph. "The peregrines came here on their own account—we didn't put a sign out saying 'room for peregrines to let.' Obviously we feel quite sorry for the pigeons, but the peregrines would be there anyway."

In the meantime, the Queen might want to keep a close eye on her birds (or hire someone who will), or consider taking advantage of Sandringham House's vast open spaces for a little indoor fly-time.

[h/t The Telegraph]

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