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Gauthier via Wikimedia Commons // CC BY-SA 3.0
Gauthier via Wikimedia Commons // CC BY-SA 3.0

Darwin’s Obsession With Barnacle Penises Makes a Lot of Sense Now

Gauthier via Wikimedia Commons // CC BY-SA 3.0
Gauthier via Wikimedia Commons // CC BY-SA 3.0

Barnacle penises are amazing. That’s not a direct quote from Charles Darwin, but it might as well have been; the naturalist was obsessed with the little crustaceans’ very large members. Now scientists say he missed out on one of the best barnacle facts: Many species can change the shape and size of their penises to suit their environment. A report of the findings was published in the journal Integrative & Comparative Biology

Relative to its body size, the barnacle has the largest penis in the animal kingdom. This is, of course, not just some hilarious joke by Mother Nature—the length is necessary in order for these sessile (non-moving) animals to reach one another. Barnacles grow in colonies clamped to rocks, piers, boats, and sometimes large animals like whales. They feed by extending little feathery sensory appendages called cirri into the water to catch plankton. 

In their resting state, barnacles are simultaneous hermaphrodites, meaning that they have both male and female parts. In many species, mating season begins when one barnacle’s egg glands begin to swell, rendering it “functionally female.” That barnacle releases chemicals into the water that tell its neighbors that it’s time to get busy. In response, they become “functional males,” unfurling their long, flexible penises into the water like party horns, questing for the right opening.   

For obvious reasons, these bizarre sexual adaptations fascinated Darwin. The naturalist devoted seven years of his life to studying barnacles, in the process compiling descriptions of the “probosciform” (elephant trunk–like) penises of hundreds of species. (We are not making this up.) 

A small sample of Darwin's barnacle collection. Image credit: FunkMonk via Wikimedia Commons // CC BY 3.0

Darwin was determined to learn all he possibly could about the animals, their anatomy, and their behavior. When he got wind that a friend of a friend had been lucky enough to see barnacle sex in action, he wrote a pretty intense letter, peppering his contact with questions. An excerpt:

Was the probosciformed penis inserted into more than one individual? For about how long [and how many] times was it inserted? Was it inserted deeply & at which end of valves? Especially did the recipient individual continue during the times exerting its cirri? Did it keep its opercula valves widely open for the reception of the organ? I am anxious to know whether this recipient was a willing agent or adulterer. or whether it was a case of rape by act. If the recipient was in full vigour, I think it wd be impossible to insert anything without its consent. Were the specimens under water at times? 

Who was the observer that I might check his authority. 

We told you he was obsessed. But he was far from the only one. Darwin’s love of (and thorough notes on) the lumpy little animals left a scientific legacy that continues to this day. Marine biologists J. Matthew Hoch and Daniel T. Schenk of Nova Southeastern University and Quest University’s Christopher J. Neufeld have spent years studying barnacles. They collected their research—and the findings of others—in the recent review paper, and they came to some very interesting conclusions. 

Barnacle reproductive organs. Image credit: J. Matthew Hoch, Nova Southeastern University

“We know that barnacles are robust in their ability to overcome environmental challenges and to mate successfully,” they write. Sometimes they do that by stretching their penises, making them thicker, or changing their shape altogether. “In the most extreme circumstances,” they say, “it degenerates and is shed during the first post-mating molt and is re-grown for the next mating season." 

These animals are “so robust” in their sexual prowess, the authors say, that in one case a barnacle with two penises was still able to mate successfully.

“As barnacle biologists,” they write, “we understand and identify with Darwin’s excitement about barnacle reproduction and look forward to new knowledge generated through the modern-day comparative approach that has yielded so many new insights.”

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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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