Category: Adaptations

How Skunks Play Fair

11/17/2022

Are skunks aggressive, dangerous animals? Or are they peaceful animals that try to avoid trouble? Well, biologists who study skunks think of them this way: if life were a sport, skunks would be known for their strong defense and for playing fair.

Skunk stinkiness comes from a chemical weapon called musk. Foxes, weasels, and some other mammals also produce musk, but skunk musk is especially strong and long-lasting. And only skunks use musk to defend themselves from attack.

Picture a skunk ambling along in the night, looking for food. It digs in the soil to get tasty earthworms and beetle grubs. The black and white fur that comes with just being a skunk sends a warning. This color pattern is unusual among mammals. It signals: "Beware, don't mess with me!"

Suppose a coyote or other predator ignores this first warning. It steps toward the skunk. When a skunk feels threatened, it faces the danger. It raises its tail and tries to look as big as possible. It stamps its feet and clicks its teeth together. It may growl or hiss.

Oh, oh! Despite all of these warnings, the coyote growls and comes closer. Now the skunk gets really serious. It twists its body into a U-shape, so it can see the coyote and also aim its rear end toward it. The skunk's tail arches over its back, away from its rear—the final warning. This gives the skunk a clear shot, and also protects its own fur from the stinky musk. Skunks try to avoid smelling bad!

From two grape-sized glands, a skunk can spray musk as a fine mist, or squirt a stream. It can squirt accurately for about 12 feet (3.7m), and hit an attacking animal right in the face. The musk stings the predator's eyes, and can blur its vision for a while. And it stinks! Animals hit with this musk learn to never bother a skunk again.

A skunk's glands store enough musk to fire a half dozen shots but then need a week or so to produce more. This is seldom a problem, since a skunk sprays only when its life seems to be in danger. Some skunks can go for months or even years without spraying musk. That's fine with them. Skunks want to avoid trouble, and "play fair" with their many warnings.

A skunks’s stripes point to where the spray comes out. A 2011 study found that animal species that choose fight over flight when faced with a predator often have markings that draw attention to their best weapon. So while a badger has stripes on his face to highlight his sharp teeth, skunks’ stripes are perfectly positioned to highlight their ability to spray potential threats. By http://www.birdphotos.com via Wikimedia Commons

Skunks are so nice that some people want to keep them as pets. The striped skunk is the most social skunk and the one most commonly domesticated. The legality of keeping skunks as pets in the US varies by state, with it being illegal in a majority of them. By Matt MacGillivray via Wikimedia Commons

Larry Pringle has written many animal books, among them The Secret Life of the Red Fox. His The Secret Life of the Skunk was published by Boyds Mills Press in 2019. It is about spring and summer in the lives of a mother striped skunk and her kits.

ML 8 Citation
Pringle, Laurence. "How Skunks Play Fair." Nonfiction Minute, iNK Think Tank, 8 Nov. 2017, www.nonfictionminute.org/how-skinks-play-fair.

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The Fish that Sees Red

5/19/2022

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Steve Jenkins

Making Sense of the Natural World

Have you ever noticed how photographs of underwater scenes have a bluish tint? Sunlight is made up of a rainbow of colors, but when it enters the water the reds and yellows in the light are quickly filtered out. The blues and greens penetrate deeper into the water and give those watery scenes their peculiar cast. Because there is very little red light in the deep sea, most of the animals that live there have never evolved the ability to see the color red. This is why many deep-sea animals are red. In the depths of the ocean, a creature that can’t be seen is safe from many predators.

There is an unusual fish that takes advantage of its fellow sea creatures’ colorblindness. The stoplight loosejaw, a member of the dragonfish family, can see the color red. Not only that, but it has a patch on its face that glows red. It also has a glowing green spot on its face, which is probably used to communicate with other dragonfish. These red and green patches explain the “stoplight” part of this fish’s name. The “loosejaw” comes from this fish’s ability to open its mouth extra wide and swallow large prey. Scientists think that the open structure of the lower jaw allows the fish to close its mouth quickly, making it difficult for prey to escape. Relative to its size, the stoplight loosejaw has one of the widest gapes of any fish, with a lower jaw measuring one-quarter of the fish’s length. It’s not easy for animals that live in the dark waters of the deep sea to find prey. Many of them, including the stoplight loosejaw, have large mouths and sharp fangs that help ensure that their prey cannot escape.

Below about 650 feet (200 meters), very little sunlight penetrates the ocean. Below 3,300 feet (1,000 meters), the only light is that produced by living creatures. Almost all deep-sea creatures can bioluminescence, or make their own light. But the light they produce is usually blue or green. When the stoplight loosejaw switches on its red spotlight, other creatures in the water are illuminated. Being blind to the color red, they don’t realize that they’ve been spotted. Dragonfish are not known as picky eaters. If one of the lit-up animals is a fish, shrimp, or other suitable prey, the stoplight loosejaw quickly grabs it and swallows it.

The stoplight loosejaw's attributes include a red spot, hinged jaws, and needle-like teeth. Illustration by Steve Jenkins

There are two kinds of stoplight loosejaws. The Northern (Malacosteus niger) shown here and the Southern. Together they are found everywhere in the world except the North and South Poles. Wikimedia Commons

Steve Jenkins has written and illustrated more than forty
nonfiction picture books, including the Caldecott Honor–
winning What Do You Do with a Tail Like This? and the
Boston Globe Horn Book honor–winning The Animal Book.
His most recent books are Apex Predators: Top Killers Past
and Present and Who Am I?, an animal guessing game
written with Robin Page.

MLA 8 Citation
Jenkins, Steve. "The Fish That Sees Red." Nonfiction Minute, iNK Think Tank, 6
June 2018, www.nonfictionminute.org/the-nonfiction-minute/
The-Fish-that-Sees-Red.

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Do Animals Ask for Help?

5/4/2022

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Aline Alexander Newman
Wildlife Storyteller

Dogs depend on us for friendship, food, and shelter. But wild animals run from people. They don’t turn to humans for help in getting out of trouble. Or do they? Until recently, most scientists thought animals could not think through multiple steps to solve problems. They believed only people could do that. But research into animal behavior shows this is not true. At least some animals think through their problems and come up with possible solutions.

Take a young, wild raven, in Elmsdale, Nova Scotia, for example. In 2013, Gertie Cleary spied the bird perched on a fence—with porcupine quills stuck in its wing and face. Porcupine quills are barbed, like a fish hook. And they really hurt. So Cleary slipped on a pair of gloves before approaching the bird. Now you might think the raven would get scared and fly away. But not this bird. This bird wanted help. It screeched in pain each time Cleary plucked out a quill. But it sat still and let her do it. “When I pulled the one out of his wing,” Cleary says, “he fell off the fence I pulled it so hard.” Once quill-free, the raven flew away.

A real-life mother goose went a step further. When one of her goslings got tangled up in a balloon string, she “called” the cops by pecking on the door of a police cruiser parked nearby. When the curious cops got out of their vehicle, she led them straight to her helpless baby.

My family and I also encountered a bird in trouble. We were walking on a nature trail when the bushes suddenly erupted with chirping. We stopped, and the chirping increased. Looking closely, we found a sparrow stuck on a thistle bush! It was hanging upside down. We felt like heroes when we freed the little creature and watched it fly away.

Birds aren’t the only animals that ask for help. In Fairfax, California, a deer approached a police car and stared at the officer inside until he noticed her broken leg. On a scorching hot day, in Adelaide, Australia, a thirsty koala begged a group of cyclists for a drink of water. And on a nature reserve, in South Africa, a desperate mother giraffe led a wildlife guide to her injured calf. In every case, kind humans helped.

Maybe someday you will rescue an animal and save a life. Wouldn’t that be great?

A baby bird in trouble— has another bird gone for help? Photo by Aline Alexander Newman

A desperate koala approaches humans, letting them know he needs liquid.

A giraffe mother was willing to ask for human help in order to save her baby.

For more stories of remarkable kitties, check out Aline Alexander Newman’s new book, CAT TALES. In it, you’ll meet Millie, the adventurous cat who rock climbs with her owner; Pudditat, who acts as a “seeing eye” cat for the family dog; Leo, a lion who changed the life of one family forever; and 20 other charming cats that will pounce into your heart. Personalized copies of CAT TALES and Aline’s other books are available at www.alinealexandernewman.com.
Aline is also a member of Authors on Call. Bring her into your classroom via interactive video conferencing. Here’s where you can learn more about her and her programs.

MLA 8 Citation
Newman, Aline Alexander. "Do Animals Ask for Help?" Nonfiction Minute, iNK Think
Tank, 9 May 2018, www.nonfictionminute.org/the-nonfiction-minute/
Do-Animals-Ask-for-Help.

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If the Earth Were a Button

1/27/2022

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David M. Schwartz
The amazing, engaging, math exponent

Imagine Earth as a button. I don’t mean you’re going to sew it onto your shirt. But imagine the planet Earth shrunk to the size of a button. (Of course Earth is not flat like a button but we’re giving our shrunken Earth the same diameter as a shirt button.)

Go ahead and draw a circle around a shirt button. Call it “Earth.” Suppose you wanted to draw Jupiter, the largest planet, at the same scale as this micro-Earth. That means you’re going to shrink it to the same fraction of its original size as our button-Earth. What size would little Jupiter be?

One way to find out would be to calculate how many times bigger the real Jupiter is than the real Earth. Earth’s diameter is about 8,000 miles (13,000 kilometers). Jupiter’s is about 88,000 miles (143,000 km). Divide the size of Jupiter by the size of Earth to see that Jupiter is about 11 times bigger.

So, since Jupiter’s diameter is 11 times that of Earth’s, put 11 buttons in a line to show the diameter of Jupiter. Then draw the circle that represents Jupiter. If you don’t have 11 buttons, just look at the picture. Did you think the Earth was a big place? Look at it compared with Jupiter!

     But what about the sun? The sun’s diameter is about 865,000 miles (1,400,000 km). That means it’s almost 10 times bigger than Jupiter. Can you find a way to draw a circle 10 times the size of our Jupiter? We’ve drawn part of it for you, on the same scale as our button-sized Earth. On the picture, it’s labeled “our arc.” (An arc is part of a circle.) Looking at the arc, you can imagine the rest of the circle and compare the sun to Jupiter and Earth. A minute ago, you thought Jupiter was big. Now it looks shrimpy compared to the sun!

      But is the sun really gigantic? Do some research to find out the size of a red giant star like the strangely named Betelguese (pronounced “beetle-juice.”) Figure out what it looks like compared to our sun, which is a medium-sized star. You may be amazed at the difference. And you thought the sun was big!

      Is anything truly big? Is anything truly small? Or does that depend on what it’s being compared to?

If the Earth were the size of a button, Jupiter’s diameter would equal eleven buttons because the diameter of Jupiter is eleven times that of Earth.

Both images are by Marissa Moss, the illustrator of David M Schwartz's book, G is for Googol.

Extend “our arc” to complete the circle and you’ll see what the sun would look like if the Earth were the size of a button. (An arc is part of a circle.)

G is for Googol: A Math Alphabet Book is a wonder-filled romp through the world of mathematics.
For more information, click here.
David Schwartz 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 Citation
Schwartz, David M. "If the Earth Were a Button." Nonfiction Minute, iNK Think
Tank, 16 Jan. 2018, www.nonfictionminute.org/the-nonfiction-minute/
If-the-Earth-Were-a-Button.

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How Skunks Play Fair

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If the Earth Were a Button

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