system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 why do crabs that live in colder temperatures have more prominent spikes whereas crabs that live in warmer climates tend to have smoother shells?
gpt
You could make some argument about the spikes on King crabs acting like hair to keep them warmer .... but It's apparently a more boring aspect of evolution that gives them defense where they need more from cold-water predators, and spiky/smooth is more due to chance.

It's more obvious when you look more broadly: lobsters have developed mostly the opposite traits - spiny in warm water, and smooth but with large claws in colder water.

In both cases, though, the more delicious variety is found in colder water.