Skip to main content Skip to navigation

How do chameleons change color?

Dear Dr. Universe, How does a chameleon change colors? -Jasmine B. 12, Nepean, Canada & Marie F., 11, Ghana

Dear Jasmine and Marie,

There’s something about a chameleon’s darting eyes, long tongue, curled tail, and ability to climb that makes it a fascinating animal to watch. Especially when it’s changing colors.

And the latest research on your question suggests that how a chameleon changes has more to do with light than scientists once thought. » More …

Why is yawning contagious?

Why is yawning contagious? -Grant, 10, Pullman, WA

Dear Grant,

When I got your question, I met up with my friend Hans Van Dongen, a scientist at Washington State University in Spokane. He works in a research lab where they study sleep. As a cat who appreciates naps, it’s one of my favorite places to visit. » More …

Why do bees make hexagons?

Why do bees make hexagons in their hives? Why not any other shape? -Aditya, 10, New Delhi, India

Dear Aditya,

When bees make hexagons in their hives, the six-sided shapes fit together perfectly. In fact, we’ve actually never seen bees make any other shape. That’s what I found out when I visited my friend Sue Cobey, a bee researcher at Washington State University.

Cobey showed me some honeycombs where the female bees live and work. Hexagons are useful shapes. They can hold the queen bee’s eggs and store the pollen and honey the worker bees bring to the hive.Dr.UBees

When you think about it, making circles wouldn’t work too well. It would leave gaps in the honeycomb. The worker bees could use triangles or squares for storage. Those wouldn’t leave gaps. But the hexagon is the strongest, most useful shape. » More …

Are animal and human bones the same?

Dear Dr. Universe, Do animals have the same types of bones and muscles as humans? -Lydia, 8

Dear Lydia,

The short answer is yes, said my friend Leslie Sprunger, a veterinarian and professor in the College of Veterinary Medicine at Washington State University. But, as always, there’s a catch. » More …

Do animals dream?

Dear Dr. Universe, Please answer this question: Do animals dream? What dreams do they get? I humbly request you to answer these questions. BYE! Or should I say MEOWY! -Prahlad R.

Dear Prahlad,

After a quick catnap and a stretch, I went to visit my friend Marcos Frank, a scientist at Washington State University who studies animal sleep.

» More …

How do mollusks move around the ocean?

If mollusks have such heavy shells to drag around with them, how have they spread all over the ocean? -Michel W.

Dear Michel,

Mollusks, from land snails and slugs to oysters and mussels in the sea, have a few things in common. They have a head. They have a soft middle part that holds their organs. Then, some have a muscle that’s known as a “foot.” » More …

Are aliens real?

Dr. Universe: Are aliens real? -Lily, 10, New York City, NY                                                                                          Is there life on other planets? -Heidi, Cincinnati, OH 

Dear Lily and Heidi,

Well, we don’t know for certain. Looking up to the stars at night, I’ve often wondered if alien cats are out chasing alien mice or taking naps on other planets.

My imagination aside, your questions are like those scientists are asking, too. And it’s no wonder we are so curious.

With billions of planets in our galaxy, including small Earth-like worlds, the possibility of life out there is an exciting thought to many people. So, humans have set out to look for planets that might support life.

In fact, this month scientists announced the Kepler spacecraft’s discovery of Earth’s closest cousin so far. Some are calling it Earth 2.0. It has a Sun just like Earth does and if it has a rocky surface like scientists predict, it might even be a good place to grow plants.

My friend Dirk Schulze-Makuch studies life in the universe as an astrobiologist at Washington State University. He explained that for life to exist on Earth it needs a few ingredients. It needs liquid water, just the right combination of elements, and a source of energy, such as our Sun. These are required for every living thing we know of, from bacteria to plants to intelligent life forms, like humans.

dru-hero-poseIntelligent life, said Schulze-Makuch, is especially rare.

“For 4.5 billion years, on our planet we’ve only had one species so technologically advanced,” he said. “That’s us.”

But the ingredients for life on Earth might not be the exact same for life on other planets, explained Schulze-Makuch.

He has studied thorny devil lizards in one of Earth’s driest desert environments to find clues about life on Mars. It can be hard for thorny devils to find liquid water in the desert, so they’ve adapted to their environment. They can grab water from the air and use special groves on their spines to get a drink.

Scientists wonder if, just as the thorny devils have adapted to their environment, life forms on other planets may also have adapted to their environments. Scientists also think about how organisms can survive in environments that aren’t like Earth’s.

Take a tiny living thing called the tardigrade. Astronauts, who observed these creatures hanging on to their space shuttle, learned the tardigrade could survive in extreme conditions of space without any kind of space suit.

“The tardigrade shows how amazingly inventive life is once it has originated on a planet,” Schulze-Makuch said. “Not only microbial life, but all life, including multicellular life.”

Schulze-Makuch thinks we will find microbes, such as bacteria or fungi, on other planets in the next ten to twenty years.

“We simply don’t know the answers,” he said. “But if it’s out there we’ll have to go find it.”

I’m keeping my paws crossed for a whole planet of cats. But finding even a tiny organism like a microbe would be a huge discovery. It would change our understanding of life as we know it.

Sincerely,

Dr. Universe

Have a question? Ask Dr. Universe. You can send her an e-mail at Dr.Universe@wsu.edu.

Q&A: Shark Week

It’s Shark Week, so I made a visit to my friend Jon Mallatt. He’s a Washington State University biologist who has studied the jaws of ancient sharks.

dru-hero-poseDr. Universe: What is something a lot of people might not know about sharks?

Jon Mallatt: Some of them, such as tiger sharks, cat sharks, and even great white sharks, have quite large brains—relative to their body weight— and are intelligent. They are not “primitive” animals. The shark relatives, Manta rays and devil rays, have even larger brains than any shark.

Dr. U: How long have sharks been around, anyways?

JM: At least 420 million years and maybe 460. It is hard to tell for sure because they do not have bone, so their skeletons usually are not preserved as fossils. Hard teeth and scales do fossilize, but may not tell us enough. Their teeth evolved from the tiny scales on their rough skin called denticles. But the first sharks may have had no teeth, or their teeth were the same as these denticles so we would not recognize them.

Older fishes without jaws evolved before sharks did, and the oldest fish of all is 520 million years old. This was not long after the first great evolution of all animals at 540 to 520 million years ago. Thus, sharks are very old, maybe appearing only 100 million years after the first animals.

Dr. U: What are some of the coolest things you’ve learned about sharks in your job as a scientist?

JM: They do not get cancer very often. They build up a lot of urea, or “pee poison” in their blood and it does not hurt them. They can feel fast, sharp pain, but not slow burning pain so they probably do not suffer. They show how successful the vertebrates became as predators after fish first evolved jaws about 460 million years ago.

Dr. U: I heard some sharks lose 1,000 teeth in their lifetime. Why do they lose them?

JM: The reason they lose teeth is that most sharks bite really hard when they chomp on their prey. That means their teeth break, come loose, and are lost, so it is good to have replacement teeth throughout life. Sharks also have lots of rows of new teeth covered by the gum inside the jaw, which are always growing up to replace the exposed teeth when they shed.

Dr. U: Woah! Okay, one last question. I think the cat shark is my favorite. Do you have a favorite kind of shark?

JM: I like the six and seven-gilled sharks, which are related. These include the cowshark, Hexanchus, and the frill-shark, Clamydoselachus. Scope them out online. Especially the frill shark: looks a like a cross between an eel and a dragon. They may represent the oldest line of living sharks and they have some primitive features. They are mysterious too, from the deep ocean.