They may seem to breathe underwater, but really
they can only breathe when their nostrils are in
the air. Their snouts are shaped so that they can
be almost all underwater, but still breathe.
Crocodiles are reptiles, so they have scaly skin.
But amphibians like salamanders don't have
scales. Not only do they sometimes have gills,
they can actually get oxygen through their skin.
The drawback is that they dry out fast.
Crocodiles can also do with less oxygen than we
can because they are "cold-blooded". This
doesn't mean that they're actually cold; it means
that they get their heat from the environment. We
get some from our surroundings, but make a lot of
our own heat. This means that our systems work a
lot harder and need a lot more food and
oxygen. Crocodiles have been around WAY longer
than humans. What do you think made them
so successful that they have stayed the same for