Category: Adaptations

Who Eats the Largest Jellyfish in the World -- and Enjoys It?

2/13/2023

Stephen R. Swinburne

Lifelong Naturalist

Lion’s mane jellyfish can grow seven feet wide with tentacles reaching a length of 100 feet. That’s the same length as a blue whale! Their bodies are 98 percent seawater. They live in the cold, boreal waters of the Arctic, northern Atlantic and northern Pacific Oceans. Slowly pulsating ocean currents carry the big jellies great distances. The long trailing, stinging tentacles capture and tear apart their prey. Swimmers beware when currents sweep lion’s manes close to shore. Their stings cause red swollen welts, and severe body contact with a lion’s mane jellyfish may be deadly.

What animal can happily and safely slurp down a lion’s mane jellyfish as if it were a big bowl of Jello™? The leatherback sea turtle!

Adult leatherbacks are the largest reptiles on earth today, averaging seven feet long. As the planet’s biggest turtle, they range from the Arctic Circle south to Antarctica, and they swim, on average, more than 6,000 miles each year. And they love lion’s mane jellyfish. As a matter of fact, lion’s mane jellyfish make up almost their entire diet. How can a seven-foot long sea turtle consume a creature armored with a hundred feet of stinging tentacles?

Often referred to as Earth’s last dinosaur, leatherback sea turtles have lived on the planet for millions of years, surviving ice ages and major extinctions. For an animal to live that long on a diet of giant blobs of gelatinous saltwater, it better be very very good at tackling and consuming its delicious but dangerous meals of giant stinging jellyfish. And, it better have developed some cool adaptations over the ages. Here’s how they do it

First off, a sharp pointed lip acts like a hook so the turtle can snag the jellyfish and hang onto it.

Second, the turtle’s mouthful of backward-pointing spines prevents the jellyfish from escaping. A scientist once said to me, while looking into the mouth of a leatherback, “It’s the last thing a jellyfish will ever see!”

Once the leatherback has consumed dozens and dozens of jellyfish, there’s the problem of all that salt in its diet. Eating too much salt will cause dehydration. No problem for the leatherback! The turtle is perfectly adapted to rid its body of all that excess salt. Salt or lacrimal glands, located near their eyes, allow leatherbacks to secret saline tears—and then they cry them away.

So the largest marine reptile on earth evolved by getting better and better at eating the most unlikely diet, the largest jellyfish on earth.

Lion's mane jellyfish. Wikimedia Commons. Photo by Dan Hershman

A leatherback turtle excreting salt from its eyes. From Arkive.org, photo © Olivier Grunewald

Leatherback turtle.

This photo of Dr. Kimberly Stewart photographing a nesting leatherback gives you an idea of the size of the turtle. Photo by Claudia Lombard, U.S. Fish and Wildlife Service, Sandy Point National Wildlife Refuge, US Virgin Islands

Steve Swinburne has written a book on sea turtles. To see information about the book as well as a study guide and video and picture gallery, click here.

Steve Swinburne is a member of iNK's Authors on Call and is available for classroom programs through Field Trip Zoom, a terrific technology that requires only a computer, wifi, and a webcam. Click here to find out more.

MLA 8 Citation
Swinburne, Stephen R. "Who Eats the Largest Jellyfish in the World -- and Enjoys It?" Nonfiction, iNK Think Tank, 12 Oct. 2017, www.nonfictionminute.org/the-nonfiction-minute/who-eats-the-largest-jellyfish-in-the-world-and-enjoys-it.

4 Comments

Alligator Smiles

1/30/2023

3 Comments

Stephen Swinburne

Lifelong Naturalist

Alligators are one of the world’s most feared predators. With rows of dagger-sharp teeth, a muscled reptilian body, a dinosaur face and eyes, alligators frighten yet fascinate people. Scientists are working hard to understand this modern-day reptile.

Dr. Daphne Soares, biology professor at the University of Maryland, was intrigued by the hunting ability of the alligator. She knew alligators have keen eyesight and excellent hearing but there was something else that made them such efficient predators, the king of the swamp. Careful focus on the dark bumps all over the animal’s upper and lower jaws led her to conclude that these bumps “were very sensitive tactile organs that can detect ripples in the water.” The ability to feel waves or ripples is one of the many features that makes the alligator an excellent predator. Once the alligator detects ripples, it swims swiftly and silently in the direction of the prey.

Alligators are carnivores. They seize and hold their prey with sharp teeth. Small quarry, such as fish and ducks, are swallowed hold. Larger victims are shaken apart into smaller, bite size pieces. Gators have between 74 and 80 teeth in the jaws at a time. When their teeth get worn down, they are replaced with new ones. Imagine that! No need for a dentist. Alligators can go through 2,000 to 3,000 teeth in a lifetime.

Alligators are a rare success story of an endangered species saved from the brink of extinction. As late as 1950s, alligators were hunted for meat and hide. They were placed on the Endangered Species list in 1967, and now thrive in the freshwater swamps and wetlands of the southeastern United States.

A smiling American Alligator displaying the bumps around its upper and lower jaws.

Steve wrote, Sea Turtle Scientist after spending time with Dr. Kimberly Stewart, “the turtle lady,” and describes her work on St. Kitts with endangered loggerhead sea turtles.

Steve is a member of iNK's Authors on Call and is available for classroom programs through Field Trip Zoom, a terrific technology that requires only a computer, wifi, and a webcam. Click here to find out more.

MLA 8 Citation
Swinburne, Stephen R. "Alligator Smiles." Nonfiction Minute, iNK Think Tank, 29 Sept. 2017, www.nonfictionminute.org/the-nonfiction-minute/alligator-smiles.

3 Comments

Bites of Passage

1/30/2023

0 Comments

Sarah Albee
Celebrating the History of Science and the
Science behind History

The insect pictured is called Paraponera clavata, commonly known as a bullet ant. It can grow to be about an inch long.

    They’re among the world’s most venomous insects, and are supposed to deliver the most painful sting of any insect, according to J.O. Schmidt. He’s an entomologist who’s been stung by pretty much every hymenopteran possible and who developed a pain scale rating that lists the relative pain caused by insects. His ratings go from 0, where the sting is as mild as the little zap you might feel while walking across a carpet in your socks, up to 4, where you might as well just lie down and scream. Bullet ants get a 4+. When he later revised his index, he described bullet ant stings as “pure, intense, brilliant pain, like walking over flaming charcoal with a three-inch nail in your heel.”

        But wait, it gets worse.

    The ants have abdominal stridulatory organs—that means they can shriek at you when threatened, which alerts the rest of the group to come boiling up out of the nest to help impale you.

    There’s a tribe of people in Brazil, deep in the Amazon forest, the Sateré-Mawé, who use bullet ants as an initiation rite to manhood. Boys have to slip on gloves that resemble oven mitts. Live bullet ants are woven into these gloves, with the stingers pointing toward the wearer’s hands. The boys have to keep the gloves on for ten minutes. Evidently paralysis of the arms sets in rather quickly, so it’s after the gloves come off that the real pain and convulsions begin—and they last at least 24 hours.

    Did I mention these ants also shriek?

Did you know that bugs played a role in history? Sarah’s book Bugged: How Insects Changed History tells the story.

MLA 8 Citation
Albee, Sarah. "Bites of Passage." Nonfiction Minute, iNK Think Tank, 26 Apr.
2018, www.nonfictionminute.org/the-nonfiction-minute/Bites-of-Passage.

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In Praise of Vultures

1/24/2023

1 Comment

Stephen R. Swinburne
Lifelong naturalist

I really like vultures. Sure, they’re ugly and they eat nasty dead things. But those are not necessarily bad characteristics.

First let’s deal with “ugly.” Vultures’ bald heads are what make them seem ugly to most people. But think about why they’re bald. Imagine thrusting your head inside the carcass of a white-tailed deer to reach the meat. A feathered head might capture bits of flesh, blood and gore and you end up with a face full bacteria and flies. Scientists believe that one reason vultures have evolved featherless heads is to aid in hygiene. A bald head stays clean and any remaining germs or bacteria are baked off by the sun. Vultures have also found that a bald head can help with temperature regulation. When it gets cold they can tuck their heads down to keep their neck covered with feathers. When it’s hot, vultures can extend their neck to expose bare skin. Their bald heads work so well that I wrote a poem about them.

Naked Head

It’s best to have no feathers,

When you stick your head in guts,

That way you don’t go walkin’ round,

Your noggin dripping schmutz.

Moving on to “eating nasty dead things,” the next time you see vultures eating a dead animal on the side of the road, be thankful! That carcass might be dead from rabies or contaminated with other harmful diseases. Vultures have the amazing ability to consume rotting and diseased flesh and stay healthy. It’s all in the stomach. Vultures possess very powerful stomach acids that destroy most bacteria and deadly viruses. In fact, vulture stomach acid is so strong it can dissolve metal! Except if that metal is lead shot -- many turkey vultures are killed every year by consuming shot that they encounter in dead deer. Vultures are the world’s natural “sanitation workers,” helping to stop the spread of disease.

I’m so appreciative of the work they do, I even wrote a poem about eating dead things:

Dead Meat

I like my meat dead,

It’s best if it’s not moving.

Don’t want to see one final twitch,

I prefer it oozing

So, the next time you see a vulture circling in the noonday sky, think about the valuable and important clean up service this bird provides to us and to the environment. Maybe I’ll write a poem about that….

Two magnificent specimens: at right, a turkey vulture showing off his bald head and ,above, an even balder American black vulture. Wikimedia Commons

My friends the black vultures didn't kill this deer. They are just going to be cleaning up the carcass. Wikipedia commons. Photo by Nathaniel Paluga.

Steve Swinburne is a science writer, but as you can see from this Minute, he likes to write poetry too. In his book Ocean Soup, he offers verses in the voices of tide-pool animals, including the barnacle, sea urchin, sculpin, mussel, starfish, hermit crab, anemone, and lobster. For more about Steve's poetry, click here.

Steve Swinburne is a member of iNK's Authors on Call and is available for classroom programs through FieldTripZoom, a terrific technology that requires only a computer, wifi, and a webcam. Click here to find out more.

MLA 8 Citation
Swinburne, Stephen R. "In Praise of Vultures." Nonfiction Minute, iNK Think Tank, 8 Dec. 2017, www.nonfictionminute.org/ In-Praise-Of-Vultures.

1 Comment

The Big Deal in Mr. Peale's Museum

1/13/2023

1 Comment

Cheryl Harness
She’s historical!

While helping to win his country’s independence from Great Britain, Captain C. W. Peale painted General George Washington’s portrait. Cleveland Museum of Art via Wikimedia

It was December 24, 1801, when bundled-up Philadelphians bought their 25¢ tickets and entered Peale’s Museum on Fifth Street. Once inside, they saw the owner’s paintings. And I’ll bet you have too—even if you’ve never heard of Charles Willson Peale. This one, for instance, of his fellow Revolutionary War soldier:

Visitors to the museum had seen Peale’s collections of butterflies, too, and other nature specimens, such as the fossilized teeth of mysterious beasts. (Who knew then that animals went extinct? Hardly anybody!) But on this extra-special Christmas Eve, people probably hurried past Peale’s handmade dioramas, with the lifelike bodies of birds and mammals that he’d stuffed and posed. Today, Mr. C.W. Peale himself was introducing his NEW ATTRACTION. People had paid an extra 50¢ just to see it! Now they looked up, up, UP at it, and were astonished.

What animal’s skeleton was eleven feet tall? Seventeen and a half feet from its bony tail to the tips of its giant, curving tusks? It was a mastodon.

It was not clear, in 1801, that mastodons weren’t the same as wooly mammoths. Wikimedia

No one had seen a live mastodon in more than ten thousand years. So how did one’s bones get to Philadelphia? Mr. Peale and other naturalists such as Thomas Jefferson, the new President-elect, wrote to one another about their studies, collections, and the latest discoveries, such as like these huge, mysterious bones in southern New York state. Some of North America’s long-gone mastodons ended up there, by the Hudson River. As soon as he heard about them, Peale hurried to see them. Then he not only figured a way to dig up the bones, but he also painted a picture of the huge excavation!

In Peale’s painting “Exhumation of the Mastodon,” he shows some of his children (He had seventeen!) and how he had to pump water out of the beast’s muddy grave. Wikimedia

Peale’s son, Rembrandt helped to draw and assemble the bones:

Rembrandt Peale drew the mastodon skeleton that he’d helped his dad to assemble. C.W. taught his many children – seventeen in all, many named after artists and scientists he admired – to draw, study, and help with his nature exhibits. Wikimedia

For years, people paid to marvel at the enormous, sensational skeleton. Later on, after Mr. Peale’s death in 1827, his museum slowly went broke. P.T. Barnum, the circus showman, bought a lot of his exhibits. Later still, they were destroyed in a fire. And the mighty bones of the mastodon wound up lost for a hundred years, until the skeleton turned up in Germany, where you can see it today.

Mr. Peale painted himself in his marvelous museum, where people could marvel at and learn from the works of Nature. Wikimedia

Hessisches Landesmuseum (Hessian State Museum), Darmstadt, Germany, where Peale's mastodon still stands today.

In Thomas Jefferson, her sixth presidential biography for National Geographic, Cheryl Harness illuminates the many sides of Thomas Jefferson: scientist, lawyer, farmer, architect, diplomat, inventor, musician, philosopher, author of the Declaration of Independence, founder of the University of Virginia, and third president of the United States. Readers meet this extraordinary man of contradictions: a genius who proclaimed that "All men are created equal" and championed the rights of "Life, Liberty, and the Pursuit of Happiness," while at the same time living a life that depended on the enforced labor of slaves.

MLA 8 Citation
Harness, Cheryl. "The Big Deal in Mr. Peale's Museum." Nonfiction Minute, iNK
Think Tank, 18 Apr. 2018, www.nonfictionminute.org/the-nonfiction-minute/
The-Big-Deal-in Mr-Peales-Museum.

1 Comment

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Who Eats the Largest Jellyfish in the World -- and Enjoys It?

Alligator Smiles

Bites of Passage

In Praise of Vultures

The Big Deal in Mr. Peale's Museum

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