Tale of the Teeth
We say fish "bite," but do they have teeth? They certainly do. Think about the awesome jaws of the great white shark or the blade-like teeth of the piranha. Although their dentition is not as spectacular, most Missouri fish have teeth. And those teeth come in a variety of shapes and sizes, from toothy muskellunge jaws to the hidden throat teeth of the common carp.
Fish teeth have evolved from scales that covered the lips of primitive fish. They are made up of a bone-like substance called dentine covered with enamel. Like our teeth, they have a pulp cavity in the center containing blood vessels and nerves.
Unlike humans, fish don't have a set of permanent teeth. Fish teeth constantly are replaced. New teeth form at the bases of the old ones, or in the spaces between them.
Fish teeth may be found in a variety of locations. Some fish have teeth on their jaw bones or on the bones of the roof of the mouth; others have patches of teeth on the tongue or pads of teeth on the gill arches in the throat. Look for fish teeth in one or more orderly rows parallel to the edges of the jaws, clustered in bands, pads and patches or in a random formation.
The teeth of gar are located mainly in the jaw. Carp, goldfish and minnows have toothless mouths, but the pharyngeal (throat) teeth are well developed and highly specialized. The northern pike is well armed with sharp, strong teeth along the sides of the lower jaw, small teeth on the upper jaw, slender, pointed teeth arranged in three parallel bands on the roof of the mouth and tooth-like projections on the gill arches.
Fish teeth come in a variety of sizes and shapes. Each is specialized for capturing and eating food. Some of the more common types include:
Canines-sharp, fang-like teeth adapted for piercing and holding prey. Walleye, whose diet consists mainly of other fish, have well developed canine teeth.
Cardiform-multiple rows of closely packed short teeth that look like the tips of a stiff brush. They are used to grasp prey in a sandpapery grip. A catfish has pads of cardiform teeth in the roof of its mouth.
- Incisors-sharply edged cutting teeth located in the forward part of the mouth. The tropical parrotfish (non-native to Missouri ) has incisors that have fused together into a beak for cutting off pieces of coral.
- Molariform-broad, flat teeth, adapted for crushing and grinding. Plant eating minnows have molariform throat teeth.
PikeThe type of tooth varies with the type of food fish eat. Sharp, pointed teeth, such as those in muskie, northern pike and gar, indicate a predatory feeding preference. Large, flat, crushing teeth indicate a diet of shellfish, corals or tough plant matter. Teeth are absent in plankton feeders, such as paddlefish and other fish that filter microscopic plants and animals from the water for their food.
Striped BassPredatory fish use teeth for seizing and holding prey until they can swallow them. In muskie, gar, pike and walleye, strong canine teeth perform this function. Pike also have special teeth in the roofs of their mouths that point backward toward the throat to prevent prey from escaping. Bass and catfish have pads of small, closely set teeth to grasp prey. Carnivorous minnows have sharp, hooked throat teeth that shred food as it passes into the stomach.
Plant-eating fish have teeth modified for scraping or grinding and generally have smaller mouths than the predators. The grass carp, a recently introduced fish in Missouri, is notorious for its diet of aquatic plants. Pond owners use them to control overabundant vegetation. Like the common carp, it has teeth in its throat that are modified to grind plant material.
The stoneroller minnow has a blade-like structure on its lower jaw for scraping algae and other vegetation from rocks, logs and other submerged objects and flattened grinding surfaces on its throat teeth. Plankton feeders, whose diet consist mainly of microscopic plants and animals strained from the water, have no teeth at all.