Crocs and gators keep their mouths open as a way to avoid overheating. Keeping cool may be the primary purpose, but for some species there's a secondary gain from the behavior. For crocodiles living in the range of the Egyptian plover, or 'crocodile bird', sitting around with their mouth open means they get free teeth cleaning from the small birds. The plover acts as both a dental hygienist and a warning system for danger.
PawNation writes, "The plover comes along and, using its sharp
little beak like a toothpick, removes the bits of meat from between
the crocodile's teeth. This feeds the plover and removes parasites
from the croc's mouth. The plover serves as a security alarm system
for the crocodile. If, while in the croc's mouth, the plover senses
danger from an oncoming animal, it screams and flies away. This
behavior alerts the crocodile to the imminent danger, so it can
slide into the water and out of harm's way."
Apr 17, 2015
Dec 14, 2012
A swan has over 25,000 feathers in its body. Snails have 14175 teeth laid along 135 rows on their tongue. The North Atlantic right whale's testes account for around 1% of its total body weight, and each of them can weigh over a thousand pounds. Africa's Nile crocodile can measure twenty feet long and weigh two thousand pounds. A horse has sixteen muscles in each ear, which allows it to rotate its ears a full 180 degrees.