Valentine’s Day conjures up sweet images of romance that humans typically associate with roses and chocolate. Casanova, however, had his own ideas about heightening sexual desire and shared large platters of raw oysters with his lovers, even though no solid evidence supported or supports this indulgence. “We sucked them in, one by one, after placing them on the other’s tongue. Voluptuous reader, try it, and tell me whether it is not the nectar of the gods!” Imagine, however, how much easier it would be to consume oysters unshucked and just crush the shells in your throat before swallowing the treat.
Perhaps efficient, but unappetizing and certainly not sexy, you say. Nevertheless, many fish perform these feats, thanks to teeth embedded in a second set of jaws that is located in their throat. These bones and teeth have likely developed independently in various types of fish, including flying fish, tilapia, and sunfish as well as in common aquarium dwellers such as angelfish.
Two adaptations of pharangeal jaws are particularly remarkable. Mobility characterizes the first. After a moray eel captures a meal with its oral teeth, it opens its pharangeal jaws, moves them forward to grasp the prize, and pulls it irreversibly into the eel’s digestive system. Researchers think that morays developed this mechanism as a result of living in tight burrows where they could not expand their bodies sufficiently to create negative pressure, necessary to draw prey deep into their mouths. Fortunately, that is not an issue with humans consuming chocolate, at least not until clothes become too tight.
An even more amazing adaptation is one characterized by strength. Black drums, also known as drums and drummers, are common along the East Coast of the United States and in the Gulf of Mexico. They typically weigh five to thirty pounds but can grow to over one hundred. Their hardened pharangeal jawbones and accompanying strong muscles are adapted to crushing crabs and other shellfish, and drums find oysters particularly delectable. Fishermen look for drums in oyster beds and sometimes see their tails sticking out of the water, which results from the drums’ habit of bottom feeding in shallow areas. And feed they do. In a day a drum can consume roughly one commercially sized oyster per pound of body weight. For me, that would be 170 oysters, far more then I would either want to shuck or to crush and spit out the shells.
Whether black drums are affected romantically by sharing a bed of raw oysters is yet to be determined. But without a pharangeal jaw, I’m sticking with chocolate and a sentimental card, both safely obtained online. Happy Valentine’s Day.
“Who knew I’d be laughing out loud when reading a science book.”