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Shark Teeth

Did you know that some shark species lose upwards of 30,000 teeth in their lifetime? Due to a strong bite and lack of a hard jawbone anchor, sharks’ teeth constantly break off or fall out. But do not worry! Sharks can have 5 to 15 rows of teeth. When a shark loses a tooth, a new one moves forward to fill in the empty spot. A shark’s first, or working, teeth are the largest. As you go back in its mouth, these teeth get smaller.

Like human teeth, shark teeth are made out of dentin. However, unlike ours, shark teeth are coated with a layer of cavity-preventing fluoride . . . so pass the candy!

Shark teeth come in a variety of shapes and sizes. Often the teeth their upper jaw are shaped differently than those in their lower jaw. The actual shape and structure of a shark’s teeth is related to the diet and hunting style of the species. For example, tiger sharks are known to eat sea turtles, seals and more or less anything that fits in their mouths, so they have large wide serrated teeth well suited to that varied diet. Meanwhile lemon sharks are primarily piscivores, or fish eaters, so their pointed rather than serrated teeth make it easier for them to grab fish and swallow them whole.

As a diver at the Greater Cleveland Aquarium, there are days when I find dozens of sandtiger, sandbar and nurse shark teeth. These three shark species have different types of teeth. The most visible of those belong to the sandtiger sharks. They have large, imposing and very sharp pointed teeth that jut out in all directions. Sandtigers can only eat things that fit within their mouths and swallow whole. Perfect for grabbing and holding prey, sandtigers use their teeth like the tines on a fork.

The smaller sandbar sharks have triangular teeth with serrated edges. They have teeth similar to a great white shark. These teeth allow sandbars to rip and cut food into bite-sized pieces.

Meanwhile, nurse sharks’ powerful jaws allow them to create suction and pull prey from hiding places in rocks and coral. Nurse sharks then use their dense and flattened teeth to crush their prey before swallowing, similar to the way humans use our molars to crunch and grind food. Their teeth are relatively small when compared to their body size.

The next time you visit the Aquarium and look up at that shark in the seatube you will know there is a lot more to a shark’s smile!

– Stephanie Q., Diver 

Pharyngeal Jaws and Green Moray Eels

Did you know that there are animals at the Greater Cleveland Aquarium that have more than one jaw? Moray eels have been known to have a second jaw, or pharyngeal jaw. The aquarium is home to several moray eels, many of which you can find in the Shark Exhibit swimming right along with the sharks and other fish.


Green moray eels are a pretty amazing animal, full of secrets. Just about ten years ago researchers discovered that these curious animals actually have a second jaw. This jaw, known as a pharyngeal jaw, is how they are able to eat. Most fish use suction to swallow. They expand their mouths to create negative pressure. This negative pressure causes water and prey to rush into their mouths allowing them to swallow their prey. Moray eels do not have this ability. Instead, they lie in wait in caves and crevices for their prey to swim by. They then burst out and grab their prey with their oral, or first set, of jaws. Their pharyngeal jaws then move forward to grip it. They can then move these jaws backwards to swallow their prey whole. They typically eat fish, shrimp, squid, crabs and octopus.

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Another secret that green moray eels have is that they are actually brown! Their bodies are covered with thick yellow mucus that gives them their vibrant green color. This mucus protects the eels from parasites and infectious bacteria.

Green moray eels are found along the western Atlantic and into the Gulf of Mexico. They’re frequently found in the Bahamas and the Caribbean and been found as far south as Brazil. When full grown they can get to be 8 feet long and weigh as much as 65 pounds. Green moray eels have few natural predators once they reach full size, although smaller eels must look out for sharks and other large predators.

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Next time you are at the aquarium make sure you look for the green moray eels. They are nocturnal in nature so they tend to spend a lot of the day hiding in the rocky structures around the exhibit. You’ll see their heads and part of their bodies sticking out. However, we often see them swimming around throughout the day. They even like to visit the divers when we are in the exhibit. Also, be sure to visit the aquarium on a Sunday, Tuesday or Thursday at 3:30 to watch the shark feed! The eels are often seen coming over for a snack as well. Look fast! Maybe you’ll just catch that pharyngeal jaw in action!