Home >> Science & Nature >> Animals & Science

What Happens When a Shark Loses a Tooth?

Perhaps the most notorious part of their anatomy, the teeth of sharks come in as many varieties as the animals themselves. Whether tiny and inconspicuous, like those of the huge filter-feeding species, or frighteningly prominent, shark dentition is uniquely structured to assure the fish an ever-present, abundant supply of food-processing equipment.

Shark Teeth
- A tiger shark has broad, serrated teeth for managing large prey.
  
  The diversity of shark teeth reflects the immense range of prey taken collectively by over 300 species. Types of smooth-hounds, like the gummy shark, have flat dentition to crush small prey. Some of the most visible teeth belong to species like sand tiger and mako sharks, which have long, slender, wickedly sharp teeth for grasping fish and other swift prey. The tiger shark has distinctively shaped, lopsided teeth with a serrated fan meeting an sharp, angled point. These formidable weapons help this big apex predator rend apart sea turtles, dolphins, seabirds and large fish. A great white shark's heavy, conical, serrated teeth are well-adapted to dispatch similarly big animals like tuna, sea lions and whale calves.
Rows and Cycles
- Developing new teeth in rear rows cycle forward to replace frontal ones.
  
  Sharks produce thousands of teeth within a lifetime. Arranged in rows within the membrane of the jaw, they cycle forward as actively used teeth are discarded or broken. Thus the loss of a tooth is no big deal for the fish: There will be another to quickly replace it. While rates of regeneration vary between species--the ReefQuest Centre for Shark Research gives nine to 36 days as a known range--sharks as a whole discard massive numbers of teeth, which accounts for their supreme abundance in seafloor sediments and beach sands.
Losing Teeth
- A white shark often looses teeth grappling with large prey like elephant seals or dolphins.
  
  Besides the common natural loss of teeth because of developing new rows, sharks often break them when they are grappling with prey, which can be a violent undertaking. A great white shark, for example, may be biting such big, powerful creatures as northern elephant seals or small cetaceans. The technique, aimed at minimizing injury to the shark, is to deliver a wrenching, catastrophic wound to the prey, which often immediately kills smaller victims. For a mature elephant seal, the white shark may hang back after the first strike, waiting for the mammal to bleed to death. Regardless, teeth will often be pulled or knocked loose during that first bite. A tiger shark might similarly lose teeth when gnashing down upon the hard shell of a sea turtle, while those of a whitetip reef shark might be dashed out as it chases a small fish through rough coral banks.
Fossilized Teeth
- Shark-tooth fossils are common.
  
  Unsurprisingly given their replaceable nature, shark teeth are supremely abundant in the fossil record, even as the mostly cartilaginous structures of the rest of the fish are only sparingly preserved. In order to be fossilized, discarded teeth usually must be buried within sediments and exposed to processes of mineralization. The mineral staining stemming from their long conversion to fossilized material usually distinguishes them from modern shark teeth, also commonly found.

Animals & Science