Anyone who knows how a skeleton looks like knows that there are spaces between the ribs. However, why does it have gaps between them? Why isn’t it a single shell?
Anyone who knows how a skeleton looks like knows that there are spaces between the ribs. However, why does it have gaps between them? Why isn’t it a single shell?
The gaps between each rib allow you to curve your chest. If it was a solid shell, you’d be forced to keep your chest perfectly straight, which would impact mobility. Evolutionary pressures preferred mobility over a “shell-like” protection.
Having a shell like protection wasn’t that necessary in most cases. Turtles needed the protection, but mammals were capable of getting away without it.
Shells are also heavy. If an deer had a shell, it wouldn’t be as fast. Also, the shell wouldn’t really help agains wolves, so that protection would come with a lot of downsides. I guess the only real benefit would be when humans are trying to stab the chest or sides of the deer with spears and arrows.