system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do dolphins and whales die when they hit land if they have to come to the surface to breathe?
gpt
They’re so heavy that when the water isn’t supporting their weight, their lungs get crushed and they die. Basically, they’re too heavy to live on land. Which is why people work so hard to get them back in the water.

Check out the concept of a buoyant force for more information.