Dear Lucy, 

Cats like me don’t have wisdom teeth. So, imagine my surprise to learn some of my human buddies get extra chompers. 

I asked my friend David Carsten about it. He studied biochemistry at Washington State University. Now he’s a dentist who teaches about dental sedation and anesthesia at Oregon Health & Science University. 

Dr. Carsten told me that humans can get three sets of permanent molars. Molars are the big grinding teeth in the back of your mouth. The third set—also called wisdom teeth—usually come in when you’re between 17 and 21 years old. If you get them at all. 

Wisdom … » More …

Dear Devyn,

I love insects, but—between you and me—I’m a little scared of spiders. I’ve been nervous around them ever since I was a kitten.

I talked about our fears with my friend Paul Strand. He’s a psychologist at Washington State University.

He told me that anxiety about insects or spiders is common. Some people even have phobias of them. That’s an intense fear that causes distress.

Many common fears involve things that were probably dangerous to our ancestors—like snakes, the dark, heights and social rejection.

Strand told me that being afraid of insects is similar.

“It’s almost like a double whammy,” he said. … » More …

Dear Hailey,

Under my lab coat, I have a splendid fur coat. That can be a problem when I work with someone who’s allergic to cats.

I asked my friend Ed Johnson about it. He teaches classes about the human body at Washington State University.

He told me that allergies happen when your immune system overreacts to a normal thing it perceives as a threat to your body. That thing can be pollen, dust, food, medicine, insect venom or something else. It can be bits of fur and shed skin called cat dander.

“The immune system evolved to protect the body,” Johnson said. … » More …

Dear William,

There are lots of unpleasant things about being sick. Leaking slimy green snot is near the top of my yuck list.

I talked about it with my friend Linda Eddy. She’s a nurse for kids. She runs the nursing program on the Vancouver campus of Washington State University.

She told me that snot is normally clear. It turns yellow or green when our bodies fight germs that can make us sick.

Snot is also called mucus. It’s a thin, slippery liquid that covers many of the surfaces inside our bodies. You can find mucus in your nose, mouth and eyes. It … » More …

Dear Sarah,

Tuna, salmon, mackerel. Cats like me are famously big fans of fish. But I’ve never looked at my afternoon sushi and wondered if it’s related to my human friends.

So, I asked one of those friends named Thomas Siek. He’s a biological anthropologist at Washington State University. He studies how humans evolved.

He told me that fish and humans are distant relatives. All vertebrates—animals with backbones—are related.

“Humans and fish aren’t close evolutionary cousins,” Siek said. “We’re part of the same phylum called Chordata. We share a common ancestor. Those in Chordata have backbones. So, this will also include birds, dogs, … » More …

Dear Ella,

I love plants. But when I hug a tree, does it love me back? Does it think about anything at all?

I talked about your question with my friend Michael Knoblauch. He’s a plant scientist at Washington State University.

He told me that whether or not plants have feelings or conscious thought is an open question. Right now, most scientists think it’s unlikely.

Animals like us feel and think—and we’re aware that we feel and think. Scientists believe that has to do with how our brains evolved.

Plants don’t have brains and nervous systems like ours. They can send and receive … » More …

Dear Prisha,

I got glasses as a kitten. I put on my new spectacles and was floored by the crisp details. I had no idea you could see individual leaves on trees. I thought everyone saw a green blur.

I talked about that with my friend Dr. Rachna Narula. She’s an eye doctor—called an optometrist—at Washington State University.

She told me that glasses help direct light to the correct spot in the eye so we can see.

“If someone’s eyeball is too short or too long, glasses help focus the image on the retina because that’s where the person can see,” Narula said.

Dear David,

I like big bugs. I cannot lie.

But which insect is the biggest? I asked my friend Rich Zack. He’s an insect scientist at Washington State University.

He told me the answer depends on how you define big.

One way is how much matter makes up an insect’s body. The insects with the most body mass are giant beetles. These include titan beetles, Goliath beetles, rhinoceros beetles and elephant beetles. They can be the size of a mouse.

Dear 1st graders,

I love bright, snowy days. That’s when you’ll find me building snowcats, throwing snowballs and watching the sun sparkle on the freshly fallen snow.

I asked my friend Von Walden why that sparkle happens. He’s an atmospheric scientist at Washington State University. Some of his research takes place near the North Pole and the South Pole.

He told me that snow sparkles because of the way snowflakes interact with the sun.

It turns out snowflakes are ice crystals. On Earth, snowflakes are hexagonal. That means they’re crystals with six sides.

Dear Maeve,

There’s just something special about those powerful, snow-white polar bears. That’s probably why it’s so hard to learn about what’s happening to their habitat.

I talked about that with my friend Anthony Pagano. He used to work with the grizzlies at Washington State University’s Bear Center. He studies polar bears in Alaska.

He told me that scientists classify polar bears as marine mammals—like whales, dolphins and other mammals that live in the ocean.

“They’re reliant on the sea ice that occurs over the Arctic Ocean,” he said. “They use the ice as a platform to catch seals.”

Polar bears spend … » More …