This is a video captured by researchers at the University Of Toronto Scarborough of an ocellate freshwater stingray chewing on a bug. Apparently this is the first time this behavior has been documented, presumably because nobody ever spent any time laying under a freshwater stingray while its eating. That's not good manners.
These elasmobranchs (sharks and rays) specialize in eating insect larvae, which are protected by extremely tough exoskeletons. The chewing motion allows the stingrays to grind down the larvae for easier swallowing.
Stingrays are able to accomplish this feat because they can extend their jaws away from their skull, while also protruding their jaws laterally, moving them left and right in a chewing motion.
Personally, I don't like chewing food. I like swallowing things whole, that way my body has to work harder to digest it. Granted I'm no TV doctor, but in my mind that burns more calories. It probably doesn't though, it's probably just harder on my anus. My poor, poor anus. It just tries to do its job and I just keep trying to melt it with homemade hot sauce.
Keep going for the whole video.