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Ask Dr. Universe Plants, Animals, and Bugs

Dr. Universe: Why do apes walk on their knuckles? - Sam, 10, Benton, Arkansas

Dear Sam, A lot of apes walk on their knuckles. Gorillas, chimpanzees and bonobos use their knuckles for stability and balance. That’s what I found out from my friend Nanda Grow, an anthropologist and wildlife biologist at Washington State University who studies primates. “Gorillas and chimpanzees both do knuckle walking, but they do different kinds,” she said. Read More ...

Dr. Universe: What are bees’ wings made of? -Natalia, 13, Kennewick, WA

Dear Natalia, Bee wings may be small, but they are really strong. I learned all about bee wings from my friend Melanie Kirby, a honey bee researcher at Washington State University. Kirby said you can think about bee wings as if they were a kite. If you make a kite out of thin tissue, it might rip. But if you make it out of a strong plastic film it will be stronger. Bee wings are made of a material called chitin (KITE-IN) and it’s a lot like keratin, the material that makes up your fingernails. Chitin is what makes up the wings on each side of the bee’s body. Read More ...

Dear Dr. Universe: I am wondering if birds can smell because I have chickens and have seen their nostrils! –Lila, 9, Philadelphia, PA

Birds have nostrils, or nares, on their beaks that can help them smell all kinds of things. That’s what I found out from my friend Dave Oleyar, a scientist with HawkWatch who recently taught a course on ornithology at Washington State University. He said that when an animal breathes air, they can also breathe in different scents or combinations of molecules. The nose has receptors that pick up on scents and send information to the brain, including a part called an olfactory bulb. It’s all part of the olfactory system. You have an olfactory system, too. This system can help animals navigate the world through a sense of smell. Read More ...

Dr. Universe: Why do some birds cheep loudly while other birds cheep quietly? -Traver, 4, Indiana 

That’s a great observation. Birds make all kinds of sounds and for lots of different reasons. When I got your question, I called up my friend Jessica Tir, a graduate student at Washington State University who studies songbirds. She said one of the main reasons a bird will make a loud sound is to attract a mate. When the birds find each other, they can make a nest for their eggs and wait for babies to hatch. Read More ...

Dr. Universe: What gives leaves their shapes? Please reply back. Thanks a ton! -Pronoy, 9, San Jose, CA, USA

We can find all kinds of leaves on our planet. Just think of tiny pine needles, fern fronds, ivy vines, or a big banana leaf. My friend Eric Roalson is a professor at Washington State University who is very curious about plants. He said there are a few things that give leaves their shapes. The shape of a leaf can depend on the family history of a plant, the group it belongs to, and the environment where it grows up. Read More ...

Dr. Universe: What is inside a blade of grass and why is it green? Green is my favorite color. We really like reading your articles in our newspaper. – Luke, 5, Ogden, Utah

Dear Luke,

I’ve been wondering the same thing lately.  Every time I go on walks, I notice new splashes of color. Watching bugs in the grass, I pretend they’re crawling through a jungle. Everything is bright and bursting with green.

When I saw your question, I knew Michael Neff would know the answer. Green is his favorite color, too. (In fact, when we talked over video, he wore a green Hawaiian shirt.) Neff researches plants at Washington State University, and he is especially curious about grasses.

If you chopped a piece of grass and looked at it with your eyes alone, you might not see much. But if you looked at it under a microscope, you’d see tiny structures containing even tinier parts.

Read More ...

Why are carrots orange? - Caden, 11, N.C.

Dear Caden,

When you picture the carrot section at a grocery store in the United States, you probably imagine rows of orange. But carrots can come in a rainbow of other colors: purple, yellow, red, and more.

And the first carrots weren’t orange at all. They were stark white.

That’s what I learned from Tim Waters, a Vegetable Specialist at Washington State University-Extension. He studies how to grow different kinds of vegetables, and helps others learn how to grow them too.

Read More ...