Uhm, rats are vertebrate mammals, and they DO have bones. Sharks are the animal whose "skeletal system" is made up entirely of cartilage.Originally posted by sunlion
Is it true that rats can squeeze themselves under doors?
It's pretty scary, but true: even very large rats can fit through
very tiny spaces. How tiny? Well, let's put it this way - if you
have a hole about the size of a nickel in your wall, you could
one day see a rat squeezing through it. Rats don't have bones.
They're made up of cartilage, which is flexible.