Frogs aren't known for their fabulous manes, but the claws of frogs are helping us learn why humans have hair -- thanks to a homeobox gene and a weird evolutionary shift.<b<br/>r/>

Hosted by: Hank Green (he/him)

Comets are famous for having space tails. But they're not the only ones! Asteroids, planets, and even stars can rock tails of their own.

Squeaks and Jessi have been having fun learning all about Australia. Squeaks wants to know more about marsupials, the special group of animals that lives almost nowhere else. So Jessi introduces him to a...

While clubs are practically synonymous with ankylosaurs, we’ve only started to get to the bottom of how they worked and how this unusual anatomy developed in the first place.

From the long extinct Stegosaurus, to tiny modern mice, all sorts of animals grow bits of bones inside their skin. These structures are called osteoderms, and they're often more than just a suit of armor.

You probably have a vague idea of what sperm does, but not all sperm are created equal, and some have even developed unique adaptations to get where they're going.

Ready your puns, viewers! From sick worm kings to uncomfortable floating snakes, today's episode is all about four types of animals that can get tied up in knots (either intentionally or...knot).

Snakes have two penises (aka hemipenes) that come in a diverse array of shapes and sizes. And they could owe it all to their lack of legs.

What’s up with ticklishness? And are other animals ticklish, too? Quick Questions has the answers!

You've heard of the Great White and the Hammerhead—but what about the lesser known but equally fierce sharks? Join Hank Green for a biting look at 7 weird sharks you're sure to love (and fear!)

From medieval knights to face shields, humans are pretty big fans of armor. But it turns out that other organisms use armor, too! Except sometimes, their armor doesn’t look like anything we’d expect. Hosted by: Rose Bear Don't Walk

One ancient predator turns out to have been able to eat much larger prey than we thought was possible, and a baby titanosaur skull gives us clues about what changes took place as sauropods grew up.

If you hear the word “baby-faced” you might picture a doe-eyed celebrity who never seems to age. But, really, you should be thinking of the axolotl. However, it is possible to transform these otherwise forever-babies, causing them to...

According to the fossils we've found, it turns out the T-Rex may look different than what we thought! Join Hank Green for a fascinating dive into the past, and a realistic look at what the King of the Dinosaurs was actually like. Let's...

We began keeping goldfish as pets more than 1,000 years ago, but their beauty wasn’t the only thing they had going for them. Goldfish had a lot of really weird biological traits that made them incredibly resilient. And in an unfortunate...

From menstrual cycles to rainfall, there are lots of claims about the moon's influence. In today's episode, Hank is here to set the record straight with 8 myths & facts about our moon.

Like dolphins, manatees, and other marine mammals, whales have nipples hidden in surprising places.

Anthony and Squeaks are spending the day watching videos all about cats and dogs of all varieties and they’re learning all sorts of interesting things along the way!

The cross product is a way to multiple to vectors in 3d. This video shows how to visualize what it means.

The midwife Xoquauhtli has a difficult choice to make. She owes a debt to her patron Teteoinnan, the female warrior goddess at the center of the Aztec seasonal festival, who must be kept happy or she will bring bad luck. Xoquauhtli...

The cross product is a way to multiple to vectors in 3d. This video shows how to visualize what it means.

It's easy to assume a cat's coat pattern is based exclusively on genetics, but that isn't entirely the case for Siamese cats. Their unique coloration comes from a combination of genetics, a fragile enzyme, and losing heat from little...

What is a vector? Is it an arrow in space? A list of numbers?

How do you tell a plane from a bird? The vertical tail, of course! By why can birds fly without a vertical tail, and how do planes use their vertical tails to stay in the air?