Category: Animals

Meet Earth's Incredible Gliders

4/29/2021

Sneed B. Collard III

Connecting Scientists and Kids

Have you ever seen a lizard hurtling over your head? How about a frog sailing down from the tree tops? I’m not making these animals up. They belong to one of earth’s most astonishing groups of animals.

            Gliders.

            Gliders travel through the air, but they don’t fly. Instead, they glide. What’s the difference? Well, to get itself off the ground, a bird, bat, or insect has to generate a force called lift. A flying animal generates lift using its wings, which are attached to powerful flight muscles. These wings move and bend in complicated motions to counteract the force of gravity.

            Gliding animals do not have muscle-powered wings. Instead, most gliding animals have special flaps or folds of skin called patagia. Like wings, the patagia generate lift—but only after the animal is already moving through the air.

            When chased by a snake, a Draco lizard leaps from its tree. Instead of plunging to its death, it spreads out its rib cage into two elegant airfoils covered with skin. As air rushes over them, these airfoils—the patagia—generate lift to keep the lizard from falling straight down. The lizard does steadily descend toward earth, but it is also riding the air. It can change directions, pull a U-turn, and control where it wants to go. In the process it can travel hundreds of feet before landing on another tree or on the ground.

            The patagia of Wallace’s frogs lie between their toes. These frogs usually live up in the trees, but when it is time to mate or lay eggs, they leap, spread out their toes, and glide to earth.

            Earth’s most astonishing gliders may be five species of gliding snakes. These snakes don’t have patagia. Instead, they flatten out their bodies and “crawl” through the air. Scientists aren’t sure if the crawling motion helps generate lift, or if lift comes mainly from a snake’s flattened shape, but the animals can glide more than 100 feet before landing.

            Most of earth’s gliding animals live in Southeast Asian rainforests, which are home to more than eighty species of gliding lizards, frogs, snakes, and mammals. In North America, we have only two gliding animals: Northern and Southern flying squirrels. Despite their name, flying squirrels don’t fly. They glide—and are adorably cute! Want to see one? Try shining a flashlight on a bird feeder at night!

A male Draco lizard extending his gular flag (throat flap) and patagi (wings). While not capable of powered flight Dracos often obtain lift in the course of their gliding flights. Glides as long as 200 feet have been recorded, Wikimedia

Wallace's frogs live almost exclusively in the trees, and leap and "fly" from tree to tree or to bushes. The membranes between their toes and loose skin flaps on their sides catch the air as they fall, helping them to glide, sometimes 50 feet or more, to a neighboring tree branch or even all the way to the ground. They also have oversized toe pads to help them land softly and stick to tree trunks. Wikimedia

Flying squirrels are able to glide from one tree to another with the aid of a patagium, a furry, parachute-like membrane that stretches from wrist to ankle. Their long tail provides stability in flight. Wikimedia

There are five recognized species of flying snake, found from western India to the Indonesian archipelago. They flatten out their bodies and parachute or glide using their ribs to become flat, and then they whip their bodies in a fast, rhythmic S-shape to stay airborne. Wikimedia

Illustrated with arresting photographs, Sneed B. Collard's Catching Air: Taking the Leap with Gliding Animals takes us around the world to learn why so many gliders live in Southeast Asia, and to find out why this gravity-defying ability has evolved in Draco lizards, snakes, and frogs as well as mammals. Why do gliders stop short of flying, how did bats make that final leap, and how did Homo sapiens bypass evolution to glide via wingsuits and hang gliders―or is that evolution in another guise?

MLA 8 Citation
Collard, Sneed B., III. "Meet Earth's Incredible Gliders." Nonfiction Minute,
iNK Think Tank, 11 Apr. 2018, www.nonfictionminute.org/
the-nonfiction-minute/meet-earths-incredible-gliders.

2 Comments

Everything is Connected: The Butterfly Effect and the Wolf

4/26/2021

1 Comment

Dorothy Hinshaw Patent

Nature’s Animal Ambassador

Have you heard about the “butterfly effect,” the idea that one small change can bring about big changes over time? This idea is important in the study of ecology, which deals with the interactions of living things and their environments. Each element of an ecosystem has its place. When one element is eliminated, it affects everything else.

The Yellowstone ecosystem centered in Yellowstone National Park provides a great example. Late in the 20th century, biologists were worried about the aspen trees there. Aspens occur in clusters that are actually clones growing up from shared root systems. Some of the Yellowstone clones were hundreds of years old, but the old, dying trees weren’t being replaced by strong young shoots. It looked like they might just die out, and no one was sure why.

When a severe drought in 1988 led to big wildfires in the park, the idea that fire might stimulate aspen growth proved wrong. Perhaps the elimination of wolves from the region in the early 20th century was to blame. Wolves? New trees? How could that be? Without wolves, the behavior of the Yellowstone elk had changed. No predators. No worry. So the elk became lazy, acting like cows, lying around in shaded areas along the rivers and creeks, munching contentedly on the juicy fresh growth of the willows and aspens.

In 1995, after much political battling, wolves were reintroduced into Yellowstone. The wolf population grew and the elk learned to be on the alert. As the wolves’ favorite food, the elk had to change their behavior to survive—no more relaxing by a stream where wolves could easy sneak up and make a meal of them! They had to move around and spend more time in open places where watching for hungry wolves was far easier.

The wolves are changing the Yellowstone landscape in positive ways. The aspens and willows are coming back. Beavers, which had almost disappeared from some parts of the park, are returning. These rodents feed on aspens and willows and use them to build their dams and lodges. Beaver dams create ponds, and the ponds provide homes for hundreds of species of plants and animals, from algae and water striders to ducks and muskrats. The willows and aspen trees around the pond are nesting sites for songbirds and homes for insects and spiders, all thanks to the wolf.

Welcome back, wolves!

This aspen shoot has been chewed to bits by elk. Dan Hartman

These aspen shoots have been allowed to grow strong and tall. Dan Hartman

Wolves on the hunt in Yellowstone. Dan Hartman

Now that the aspens and willows are returning, so are the beavers. Dan Hartman

Dorothy Hinshaw Patent's book, When the Wolves Returned: Restoring Nature's Balance in Yellowstone, is an IRA/CBC Teachers' Choices book, an ALA Notable Children's Book, A Book Sense Pick, and an Outstanding Science Trade Book for Children, as well as receiving the Orbis Pictus Honor Book Award. Booklist calls it "A great choice for elementary units about science and environmental protection," and Kirkus gave it a starred review. Click here to read the reviews.

Dorothy Hinshaw Patent 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
Patent, Dorothy Hinshaw. "Everything Is Connected: The Butterfly Effect and the
     Wolf." Nonfiction Minute, iNK Think Tank, 27 Mar. 2018,
     www.nonfictionminute.org/the-nonfiction-minute/
     Everything-is-Connected-The-Butterfly-Effect-and-the-Wolf.

1 Comment

Did the Hero Dog Survive?

4/20/2021

2 Comments

Laurence Pringle

celebrating nature, inspiring good writing

In 1804, President Thomas Jefferson sent Meriwether Lewis, William Clark, and a team of men on a vital mission to explore the wild, unmapped West.

Lewis brought his dog along. According to journals kept by several of the explorers, the dog helped a lot. He retrieved animals that had been shot for food. He scared away grizzly bears, and a bull bison that charged into camp.

The old journal pages are often hard to read, and this led to a misunderstanding of the dog's name. People thought that he was called Scannon. Not until 1985 did a historian carefully examine every mention of the dog. He found that Lewis had actually named the dog Seaman. The dog was a Newfoundland, a breed often kept on ships. They are great swimmers, and could save people from drowning.

In the expedition's journals, Seaman was last mentioned in July, 1806, two months before the explorers returned from the West and reached the little town of St. Louis on the Mississippi River. After that, there is no word about the dog in letters or reports written by Lewis, Clark, or others.

The mystery of what happened to Seaman was solved in the year 2000, thanks to the work of historian James Holberg. He had found a book, written in 1814 by historian Timothy Alden, which told of a little museum in Virginia. Alden found a dog collar displayed there that William Clark had given to the museum. On the collar were these words: "The greatest traveller of my species. My name is SEAMAN, the dog of captain Meriwether Lewis, whom I accompanied to the Pacifick ocean through the interior of the continent of North America."

The collar was later destroyed by fire, but in his 1814 book Timothy Alden also wrote further details about Seaman. Historians report that after the expedition, Meriwether Lewis' life became one of failure and despair. In October 1809 he took his own life. Alden wrote that Seaman was there when Lewis was buried, and "refused to take every kind of food, which was offered to him, and actually pined away and died with grief upon his master's grave."

People who know Newfoundland dogs say that this could be true, because these dogs are fiercely loyal to their owners. Unless historians find some new evidence, that is how the life of this great dog hero ended.

Meriwether Lewis (left) and William Clark

Eugene L. Daub's 2000 sculpture group on Quality Hill in Kansas City, Missouri includes figures of York, the slave who accompanied Lewis and Clarke on the expedition, and the Newfoundland dog Seaman.

The Lewis and Clark Expedition was the first American expedition to cross what is now the western portion of the United States, departing in May 1804, from near St. Louis on the Mississippi River, making their way westward through the continental divide to the Pacific coast. Seaman was along on every bit of the round trip expedition of over seven thousand miles. However, like the explorers, he traveled many of those miles on a keel boat or canoe--up the Missouri and other rivers, downstream to the Pacific Ocean, and then the return journey to St. Louis in 1806.

Laurence Pringle has written a book about Seaman. This richly detailed account of the Lewis and Clark expedition includes its planning, its adventures and discoveries, and its aftermath. With intriguing sidebars, historical illustrations, journal excerpts, and original art, this account of what became known as the Corps of Discovery features the remarkable dog that was the expedition's most unusual member. For more information click here.

MLA 8 Citation
Pringle, Laurence. "Did the Hero Dog Survive?" Nonfiction Minute, iNK Think
Tank, 29 Jan. 2018, www.nonfictionminute.org/the-nonfiction-minute/
did-the-hero-dog-survive.

2 Comments

Smelling Feet or Smelly Feet?

4/19/2021

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Dorothy Hinshaw Patent
Nature’s Animal Ambassador

Do your feet sometimes smell rotten? Do you wish you could toss out your shoes and start with a new pair? We make jokes about smelly feet, but smell and feet have a very different relationship among some insects.

Take butterflies. Have you ever watched a butterfly flit over a plant, gently touch its feet to a leaf, and then fly on to the next leaf? That butterfly isn’t being picky about where to land. It’s hunting for the right kind of leaf for laying its eggs. It’s “smelling” the leaf with its feet!

Actually, we need to qualify that statement a bit. Some writers will say the insect is “smelling” the leaf while others may write that it’s “tasting” the leaf. Smelling and tasting are forms of “chemoreception,” or sensing of chemicals. Smell usually refers to sensing from a distance while tasting generally means actually touching the nerve cells that sense a chemical.

We humans have cells in our noses that send messages to our brains about chemicals in the air. We call that our sense of smell. We have cells on our tongues that sense chemicals dissolved in liquid in our mouths. That’s taste.

That butterfly doesn’t have a nose, and its mouth is a long tube for sucking up nectar from flowers. Its chemoreceptors are elsewhere, like on its feet, around its mouth, and on its antennae. Most butterflies lay their eggs on the plants that the hatched caterpillars will eat. Some species are very specific about what plants their young can feed on. Take the postman butterfly, which lives in Central and South America. Its caterpillars can only survive on certain species of passionflower vines. Other species are poisonous to their offspring.

The female postman butterfly has dozens of special nerve cells on her feet called “gustatory sensilla.” Scientists think that when she touches gently down on a leaf, these cells can sense chemicals there that would be poisonous to her caterpillars. She avoids laying eggs on those leaves. But when she finds a plant that will nourish her young, she’ll alight and lay her eggs.

Now take your shoes off and move your feet around on the floor. The only nerve endings on your feet are ones that sense touch. But then, you don’t need to be able to smell the ground you walk on. Imagine how gross it would be if your feet could smell the insides of your socks and shoes—yuck!

In these photographs taken through a microscope, you can see the sensory sensilla (arrow) on the feet of the female butterfly on the right, which the male on the left doesn't have. From PLoS Genet. Jul 2013; 9(7): e1003620.

Above: Postman butterfly feeding Right: Female postman butterfly laying an egg. As you can see from these two photos, the postman butterfly can have a variety of color patterns. From Heliconius.org

A dog’s nose is 300 times more powerful than a human nose, so it’s no wonder that dogs use their incredibly advanced sense of smell to do some very important jobs. In Super Sniffers, Dorothy Hinshaw Patent explores the various ways specific dogs have put their super sniffing ability to use: from bedbug sniffers to explosive detectors to life-saving allergy detectors . . . and more. This dynamic photo-essay includes first-hand accounts from the people who work closely with these amazing dogs. For more information, click here.

Dorothy Hinshaw Patent 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
Patent, Dorothy Hinshaw. "Smelling Feet or Smelly Feet?" Nonfiction Minute, iNK
Think Tank, 23 Jan. 2018, www.nonfictionminute.org/the-nonfiction-minute/
Smelling-Feet-or-Smelly-Feet.

0 Comments

Tardigrades Make the Grade

1/22/2021

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Laurie Ann Thompson
Inspiring and empowering young readers

Are you tougher than a tardigrade? I don’t think so.

These typically water-dwelling animals may be microscopic in size (barely half of a millimeter when fully grown!), but boy are they fierce. Sometimes called “water bears,” they’re anything but cuddly. Each of their eight legs is decked out with wicked claws. Some tardigrades have full body armor. Most have specialized "sucker" mouths to pierce the cells of plants and animals and suck out their nutrients, while others prefer to consume their tiny prey whole… and that prey might even be another tardigrade!

Aside from ending up as someone else’s dinner, though, tardigrades are practically indestructible. They can survive in just about any conditions and take on just about anything life has in store for them. Starvation? No worries there: Tardigrades can go without food for at least 10 years. What about water, you say? No problem. They’ll just suspend their life activities and wait until the drought is over. They can survive at pressures more than six times that of the deepest ocean trenches. And, you’d die from radiation poisoning long before a tardigrade would even notice. Scientists have even tried shooting them into outer space… and the tardigrades survived.

Because of their ability to live practically anywhere, these little guys are practically everywhere. Tardigrades can be found on top of Mount Everest and in boiling hot springs, in desert dunes and rainforest canopies, in freshwater lakes and salty oceans, on your roof, outside your front door… maybe even in your bed or on your dinner plate! There are billions and billions of tardigrades… and they’re always making more!

Fortunately, there’s no need to worry—tardigrades are completely harmless to humans. In fact, tardigrades may actually end up being our best friends someday. Because they can do so many things that other Earthly animals can’t, scientists are studying tardigrades to try to find solutions to all kinds of problems. Want to dry something out to preserve it, then rehydrate it later? Study how tardigrades do it. Wish we could safely reanimate something that has been frozen? Learn from the tardigrades. Need to protect cells from being damaged by radiation? Figure out why tardigrade cells can withstand it.

Who knows? Someday the tough tardigrades might teach us all kinds of handy tricks!

Tardigrades are short and plump, with four pairs of legs, each with four to eight claws also known as "disks." Schokraie E, Warnken U, Hotz-Wagenblatt A, Grohme MA, Hengherr S, et al. (2012)/Wikimedia Commons

An adult Milnesium tardigrade, an example of more than 1,000 species of the tiny animal. Bob Goldstein and Vicky Madden, UNC Chapel Hill/Wikimedia Common

This video shows a tardigrade in real time at 100X magnification. Dmitry Brant via Wikimedia Commons

Laurie Ann Thompson and coauthor Ammi-Joan Paquette begin a fascinating new series with Two Truths and a Lie, a book that presents some of the most crazy-but-true stories about the living world. Some of the stories are too crazy to be true—and readers are asked to separate facts from fakes! "A brief but savvy guide to responsible research methods adds further luster to this crowd pleaser.” —ALA Booklist (starred review)

MLA 8 Citation
Thompson, Laurie Ann. "Tardigrades Make the Grade." Nonfiction Minute, iNK Think
Tank, 21 Mar. 2018, www.nonfictionminute.org/the-nonfiction-minute/
Tardigrades-Make-the-Grade.

0 Comments

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Meet Earth's Incredible Gliders

Everything is Connected: The Butterfly Effect and the Wolf

Did the Hero Dog Survive?

Smelling Feet or Smelly Feet?

Tardigrades Make the Grade

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