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16 Fun Facts About Tortoises

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May 23 is World Turtle Day. Celebrate the ultimate slow and steady land reptile with these fun facts about tortoises.

1. A tortoise is a turtle, but a turtle isn't a tortoise.

A turtle is any shelled reptile belonging to the order Chelonii. The term "tortoise" is more specific, referring to terrestrial turtles. (Of course, there's always an exception. In this case, the land-dwelling box turtle.) Tortoises are usually herbivorous and can't swim.

One easy way to tell 'em apart: look at their feet and shells. Water turtles have flippers or webbed feet with long claws, and their shells are flatter and more streamlined. Tortoises have stubby, elephant-like feet and heavier, domed shells.

2. A group of tortoises is called a creep.

But you won't see a creep very often. (Not that kind, anyway.) Tortoises are solitary roamers. Some mother tortoises are protective of their nests, but they don't care for their young after they hatch.

3. Tortoises inspired the ancient Roman military.

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During seiges, soldiers would get in testudo formation, named after the Latin word for tortoise. The men formed rows and held shields in front or above them to completely shelter the unit.

4. "Testudinal" means "pertaining to or resembling a tortoise or tortoise shell."

Go ahead. Compliment your friend's testudinal sunglasses.

5. Tortoises have an exoskeleton AND an endoskeleton.

The shell has three main parts: the top carapace, the bottom plastron, and the bridge that fuses these pieces together. You can't see them, but every tortoise has ribs, a collar bone, and a spine inside its shell.

6. The scales on the carapace are called scutes.

Made of the same keratin found in fingernails and hooves, scutes protect the bony plates of the shell from injury and infection. The growth rings around scutes can be counted to determine the approximate age of wild tortoises.

7. The lighter the shell, the warmer the origin.

Amanda Green

Tortoises from hot places tend to have lighter-colored shells than tortoises from cooler areas. The light tan sulcata originates from the southern part of the Sahara Desert.

8. They can't swim, but tortoises can hold their breath for a long time.

They're extremely tolerant of carbon dioxide. It's a good thing—tortoises have to empty their lungs before they can go into their shells. You'll often hear them exhale when they're startled and decide to hide.

9. And yes, their shells are sensitive to touch.

Shells have nerve endings, so tortoises can feel every rub, pet, or scratch ... and sometimes they love it. Note: This delightful creature is a turtle, not a tortoise.

10. Sulcatas are one of the most popular pet tortoises—and one of the biggest.

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Get ready to move to the suburbs and amend your will. Sulcatas are the third largest tortoise species in the world, behind the Galapagos and Aldabra giant tortoise. They can live more than 100 years and weigh up to 200 pounds.

11. Charles Darwin and Steve Irwin cared for the same tortoise, a Galapagos gal named Harriet.

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Darwin is said to have collected and named Harriet back in 1835. She was sent to England and eventually wound up at Australia Zoo, founded by Steve Irwin's parents. She finally passed on in 2006, the same year as the Crocodile Hunter's fatal encounter with a stingray.

12. Tortoises reach sexual maturity with size, not age.

It's a boy, err, uhh... You won't be able to tell a tortoise's sex until it reaches a certain size, which varies by breed. The most obvious tell is the plastron—for mating purposes, it's flatter on females and curved on males. Males also tend to be larger and have longer tails.

If you're a tortoise owner who prefers surprises, just wait for your pet to come out of his or her shell. Males will eventually display their private parts while soaking. And it's not uncommon for females to lay eggs, even without a mate to fertilize them.

13. They're the ultimate conservationists.

Tortoises can extract water and nutrients from even the most paltry bites. Their hindgut system works like a double digestive tract, separating water from their waste. When water's scarce, they'll hang on to water waste and simply excrete the urates, which look like white toothpaste.

14. They can smell with their throats.

Like other reptiles, tortoises detect the faintest of smells with the vomeronasal organ, or Jacobson's Organ, on the roof of their mouths. Instead of flicking their tongues, they pump their throats to circulate air through the nose and around the mouth.

15. Tortoises won the space race.

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In 1968, the Soviet Union's Zond 5 spacecraft was the first to circle the moon and return safely to Earth. The tortoises on board lost about 10 percent of their body weight, but were still ready for a meal when they touched down. That's one giant step for tortoisekind.

16. They might be smarter than we thought.

Slow and steady won the race in 2006 when scientist Anna Wilkinson placed a tortoise and rat in the same maze. The reptile was better at navigating the maze to find food, making sure it didn't revisit the same area twice. When cognitive landmarks were removed for a second trial, the tortoise systematically visited each section of the maze to find food. The rat wasn't as methodical. Previous research hasn't shown tortoises to be so clever, though: Wilkinson suspects cold lab temperatures are to blame. Later research found that tortoises use gaze-following to learn from the behavior of other animals.

All images courtesy of Thinkstock unless otherwise stated. 

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technology
Man Buys Two Metric Tons of LEGO Bricks; Sorts Them Via Machine Learning
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iStock // Ekaterina Minaeva

Jacques Mattheij made a small, but awesome, mistake. He went on eBay one evening and bid on a bunch of bulk LEGO brick auctions, then went to sleep. Upon waking, he discovered that he was the high bidder on many, and was now the proud owner of two tons of LEGO bricks. (This is about 4400 pounds.) He wrote, "[L]esson 1: if you win almost all bids you are bidding too high."

Mattheij had noticed that bulk, unsorted bricks sell for something like €10/kilogram, whereas sets are roughly €40/kg and rare parts go for up to €100/kg. Much of the value of the bricks is in their sorting. If he could reduce the entropy of these bins of unsorted bricks, he could make a tidy profit. While many people do this work by hand, the problem is enormous—just the kind of challenge for a computer. Mattheij writes:

There are 38000+ shapes and there are 100+ possible shades of color (you can roughly tell how old someone is by asking them what lego colors they remember from their youth).

In the following months, Mattheij built a proof-of-concept sorting system using, of course, LEGO. He broke the problem down into a series of sub-problems (including "feeding LEGO reliably from a hopper is surprisingly hard," one of those facts of nature that will stymie even the best system design). After tinkering with the prototype at length, he expanded the system to a surprisingly complex system of conveyer belts (powered by a home treadmill), various pieces of cabinetry, and "copious quantities of crazy glue."

Here's a video showing the current system running at low speed:

The key part of the system was running the bricks past a camera paired with a computer running a neural net-based image classifier. That allows the computer (when sufficiently trained on brick images) to recognize bricks and thus categorize them by color, shape, or other parameters. Remember that as bricks pass by, they can be in any orientation, can be dirty, can even be stuck to other pieces. So having a flexible software system is key to recognizing—in a fraction of a second—what a given brick is, in order to sort it out. When a match is found, a jet of compressed air pops the piece off the conveyer belt and into a waiting bin.

After much experimentation, Mattheij rewrote the software (several times in fact) to accomplish a variety of basic tasks. At its core, the system takes images from a webcam and feeds them to a neural network to do the classification. Of course, the neural net needs to be "trained" by showing it lots of images, and telling it what those images represent. Mattheij's breakthrough was allowing the machine to effectively train itself, with guidance: Running pieces through allows the system to take its own photos, make a guess, and build on that guess. As long as Mattheij corrects the incorrect guesses, he ends up with a decent (and self-reinforcing) corpus of training data. As the machine continues running, it can rack up more training, allowing it to recognize a broad variety of pieces on the fly.

Here's another video, focusing on how the pieces move on conveyer belts (running at slow speed so puny humans can follow). You can also see the air jets in action:

In an email interview, Mattheij told Mental Floss that the system currently sorts LEGO bricks into more than 50 categories. It can also be run in a color-sorting mode to bin the parts across 12 color groups. (Thus at present you'd likely do a two-pass sort on the bricks: once for shape, then a separate pass for color.) He continues to refine the system, with a focus on making its recognition abilities faster. At some point down the line, he plans to make the software portion open source. You're on your own as far as building conveyer belts, bins, and so forth.

Check out Mattheij's writeup in two parts for more information. It starts with an overview of the story, followed up with a deep dive on the software. He's also tweeting about the project (among other things). And if you look around a bit, you'll find bulk LEGO brick auctions online—it's definitely a thing!

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Health
One Bite From This Tick Can Make You Allergic to Meat
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We like to believe that there’s no such thing as a bad organism, that every creature must have its place in the world. But ticks are really making that difficult. As if Lyme disease wasn't bad enough, scientists say some ticks carry a pathogen that causes a sudden and dangerous allergy to meat. Yes, meat.

The Lone Star tick (Amblyomma americanum) mostly looks like your average tick, with a tiny head and a big fat behind, except the adult female has a Texas-shaped spot on its back—thus the name.

Unlike other American ticks, the Lone Star feeds on humans at every stage of its life cycle. Even the larvae want our blood. You can’t get Lyme disease from the Lone Star tick, but you can get something even more mysterious: the inability to safely consume a bacon cheeseburger.

"The weird thing about [this reaction] is it can occur within three to 10 or 12 hours, so patients have no idea what prompted their allergic reactions," allergist Ronald Saff, of the Florida State University College of Medicine, told Business Insider.

What prompted them was STARI, or southern tick-associated rash illness. People with STARI may develop a circular rash like the one commonly seen in Lyme disease. They may feel achy, fatigued, and fevered. And their next meal could make them very, very sick.

Saff now sees at least one patient per week with STARI and a sensitivity to galactose-alpha-1, 3-galactose—more commonly known as alpha-gal—a sugar molecule found in mammal tissue like pork, beef, and lamb. Several hours after eating, patients’ immune systems overreact to alpha-gal, with symptoms ranging from an itchy rash to throat swelling.

Even worse, the more times a person is bitten, the more likely it becomes that they will develop this dangerous allergy.

The tick’s range currently covers the southern, eastern, and south-central U.S., but even that is changing. "We expect with warming temperatures, the tick is going to slowly make its way northward and westward and cause more problems than they're already causing," Saff said. We've already seen that occur with the deer ticks that cause Lyme disease, and 2017 is projected to be an especially bad year.

There’s so much we don’t understand about alpha-gal sensitivity. Scientists don’t know why it happens, how to treat it, or if it's permanent. All they can do is advise us to be vigilant and follow basic tick-avoidance practices.

[h/t Business Insider]

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