You're probably going to yawn during this episode. Sorry. We'll cover why the old 'more oxygen' explanation didn't survive testing, the brain-cooling theory, and why yawns spread between people, chimps, and sometimes from you to your dog. Why the Hell Is That? is an Origami Penguin Press production.

Monkeys have tails. We have a tailbone that hurts like crazy when you fall on it. In 2024, scientists reported a 'jumping gene' that may have helped switch off tails in our ancestors around twenty-five million years ago. Here's the evidence and what it cost us. Why the Hell Is That? is an Origami Penguin Press production.

They live in water, so how could they ever need a drink? Turns out ocean fish drink seawater all day long, while freshwater fish basically never do. Here's how fish manage salt and water, and what salmon do when they switch between the two. Why the Hell Is That? is an Origami Penguin Press production.

Pour seawater into a glass and it's clear. Look at the ocean and it's deep blue. Is it just reflecting the sky? Partly, but that's not the main answer. Water itself has a very faint color, and you only notice it when there's a lot of it. Why the Hell Is That? is an Origami Penguin Press production.

Plants live on sunlight, so why do they throw away green, right in the middle of the brightest part of the spectrum? A black leaf would catch more energy. Find out how chlorophyll works, why leaves change color in the fall, and the ideas scientists have for why green won. Why the Hell Is That? is an Origami Penguin Press production.

Every night your brain screens a bizarre movie you didn't write and forget by breakfast. Here's what's happening in your head during REM sleep, the leading theories for why we dream, and the uncomfortable truth that science still doesn't fully know. Why the Hell Is That? is an Origami Penguin Press production.

The 'wood wide web' is one of the most shared science stories of the last decade. Trees feeding their babies, sending warnings through fungus. In 2023, a team of scientists went back and checked the evidence. The truth is messier, more honest, and honestly more interesting. Why the Hell Is That? is an Origami Penguin Press production.

A single puffy cloud can hold over a million pounds of water. So why isn't it falling on your car? Here's the physics of floating clouds, how tiny droplets beat gravity, and what finally makes them let go as rain. Why the Hell Is That? is an Origami Penguin Press production.