Why do we have blood and what does it do?

Deep in the basement of the San Diego Natural History Museum, there are thousands of jars filled with preserved reptiles and amphibians. In this episode, But Why takes a tour with collections manager Adam Clause to answer your questions about lizards! How do lizards climb walls? ...  Show more

But Why turns ten years old on April 1, 2026! To celebrate this milestone, we’re listening back to our very first episode. We’ve got owls and turtles and bears. Naturalist Mary Holland gets into the details about hibernation–including the questions you may not even have thought t ...  Show more

Why does blood not stick to human skin like a permanent marker, yet stains things like clothes really badly? How does circulation work after an amputation? How many blood types are there? What does A B & O mean? If blood in your veins looks blue, why do we never see blue blood wh ...  Show more

If you’ve ever smacked a mosquito on your arm, you might have seen a little smear of red blood on your skin afterward. But just whose blood was it? Do we have the same blood as insects? We asked biologist Claire Rusch from the University of Washington to help us find the answer. ...  Show more

Many people battling symptoms, conditions, or chronic illness are subjected to routine blood draws and tests. How can these routine blood draws affect the body? In this episode, I uncover important truths about blood draws and reveal why the blood testing and donation system is b ...  Show more

Knowing your blood group is handy information if you need a blood transfusion, or even an organ transplant. And it's essential information for the blood bank recruiting donors who match your blood type—and for people needing a blood product.