Sometimes, yes, they pant. This can also happen when they're kind of freaking out too. When I was taking my cat home from a cat motel, in his cat cage, he was panting like a dog. It was a hot day, and he was a bit uncomfortable aswell. I'm not sure if it's bad if it happens, but if it does, try to cool your cat down and calm it.
Crocodiles are often seen on the beach, looking like they are asleep, with their mouths open. What they are doing is basking, they keep their mouths open to regulate their body temperature. People sweat, dogs and cats pant, and crocodiles open their mouths :)
Cats may drool while sleeping due to relaxation and contentment, which can cause their muscles to relax and their mouths to open slightly, leading to drooling.
I don't have any idea!
Cats Will Normaly Stick Their Tongues out when they lick their selfs and then forget where to put it at when their done.. that shows how lazy they realy are :]
to eat, or to sing, or to vomit into the mouths of their children
eels must open and cloth their mouths constantly in order to circulate water over their gills
all cats put their babys in their mouths, its how they carry them around. and no, it doesn't hurt the babys! because the kittens have a spot that is kinda like bluber, were cats, and even humans can pick them up from with out it hurting them.
for food
No.
they open their mouths and eat.
Many fish swim with their mouths open. They swim with their mouths open because the water goes into their mouths and out their gills, which is how they breathe.
No, cats can also breathe through their mouths. They have the ability to breathe through both their noses and mouths, depending on the situation.