graphic of shark silhouette with "Shark" written in it

What’s Life Like for a Shark?

Sharks aren’t just like other fish. They hunt, eat, fight, and reproduce in so many surprising ways. They even have a sixth sense! 

How Do Sharks Reproduce?

Baby catshark in its egg case on a piece of coral

catshark embryo in egg case 
 

Unlike most fishes, which release sperm and eggs into the water, sharks fertilize eggs inside the female’s body.

Many shark mothers keep eggs inside their uteruses until they hatch. Some embryos eat unhatched eggs inside their mother. Some even eat other embryos!

Other sharks lay their eggs in egg cases to keep them safe. Egg cases can have sharp prongs to help them hang onto seaweed and corals. 

FUN FACTS:

  • Fluorescent sharks lay fluorescent egg cases.
  • Very long-lived Greenland sharks may not reproduce until they are 150 years old!
  • One female whale shark was found with 300 eggs inside it, some of them already hatched and ready for live birth.

How Do Sharks Eat?

Sharks have all kinds of jaws and teeth—and all kinds of other body parts that they use to hunt with, too.

For example, sawsharks and sawfishes slash fish with their sawlike nose extensions, or rostrums. 

collage of sawshark and a close up showing its teeth

largetooth sawfish

Thresher sharks whip prey with their tails. Lantern sharks attract prey with their glowing bellies.

shark with tall long tail

thresher shark

shark that glows blue

lantern shark

Some sharks bite down hard on their prey, breaking their teeth. No problem! New teeth keep growing in, through a system that's a little like a conveyor belt. Almost all sharks grow new teeth! Most sharks and rays can extend their upper jaws forward while biting. And high-stress areas, like jaws, have layers of calcified cartilage to reinforce them so they don’t break.

brown hexagonal pattern that makes up shark cartilage

shark cartilage

shark jaw showing multiple rows of teeth

shark teeth

Can You Match the Jaw to the Feeding Style?

1

FILTERING: The largest sharks and rays eat by filtering, which means taking in large amounts of water, getting rid of the water, and eating the millions of tiny animals left behind.

Which jaw is for filtering?

make shark jaw
whale shark jaw
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You got it!

ANSWER:

The whale shark uses its gaping mouth to filter millions of tiny prey animals from the water.

collage of whale shark jaw and whale shark with mouth open
Question 1 of 4
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2

BITING: Some sharks have teeth that point inward at an angle, which helps them hang on to fast-moving prey.

Which jaw is for biting?

make shark jaw
image of the circular jaw of a cookie cutter shark
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You got it!

ANSWER:

The shortfin mako shark bites onto fast-moving prey, like seals or fishes, with very pointy teeth that angle slightly inward.

collage of mako shark jaw and a mako shark swimming with its mouth open
Question 2 of 4
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3

SAWING: Not every shark bite is designed to kill. Some sharks just want to saw off a piece of their prey’s flesh to munch on.

Which jaw is for sawing?

image of the circular jaw of a cookie cutter shark
whale shark jaw
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You got it!

ANSWER:

Cookie cutter sharks use the evenly-spaced teeth of their jaws to cut out pieces of a prey’s flesh. They leave behind bite marks, like on this seal:

an image of a cookie cutter shark with mouth open and an image of a circular bite taken from the side of a dolphin
Question 3 of 4
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4

GRINDING: Some sharks eat lots of animals with shells, so they need to grind up their prey.

Which jaw is for grinding?

make shark jaw
image of a Port Jackson shark jaw
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You got it!

ANSWER:

Port Jackson sharks use their jaws to grind up the shells of sea urchins and other prey, to get at the soft flesh inside. Those round knobs on their jaws are teeth!  

gif of a Port Jackson shark zooming in on its mouth
Question 4 of 4
You got out of 4 right on the first guess.

How Do Sharks Use Electricity to Find Their Prey?

SHOW HIDE TRANSCRIPT

HOW DO SHARKS USE ELECTRICITY TO FIND THEIR PREY?

[scalloped hammerhead shark, with head jutting squarely from body, swims directly over camera]

Voiceover: Sharks use familiar senses

[great hammerhead shark captures prey from seafloor, and the eye on the tip of its squared head passes close to camera]

Voiceover: like smell and hearing when they hunt.

[smalltooth sand tiger shark swims close to rocky seafloor]

Voiceover: But they use extra senses, too. One of these is electroreception. 

[a large group of mobula rays swim, spaced at regular intervals from each other in a patchwork pattern]

Voiceover: Did you know all living things give off weak electrical fields?

[a spookfish with a narrow, upturned snout, slowly waves its pectoral fins] 

Voiceover: We can’t sense that electricity, but sharks can! 

[tiger shark swims straight toward camera, with a blunt snout]
Voiceover: Sharks use special pores in their snouts, called

[close-up photograph of a tiger shark shows small holes covering its snout; a label appears that says ‘ampullae of Lorenzini’]

Voiceover: ampullae of Lorenzini, to sense electrical fields.

[cross-section drawing shows a pore that opens to the water. The pore leads to a tube with sense cells at the bottom of it.]

Voiceover: These pores are tiny holes leading to tubes filled with jellylike mucus.

[seals swim under a floating mat of seaweed]

Voiceover: A prey animal’s electrical field makes the mucus vibrate.

[A bowl of orange jello sits on a table. Someone places another bowl of Jell-o next to it, which jiggles.]

Voiceover: Think of how a bowl of Jell-O wiggles with every vibration.

[many scalloped hammerhead sharks, with heads that jut out squarely from their bodies, swim underwater]

Voiceover: A shark can find its prey by feeling which ampullae are wiggling and how much. Sharks also use electroreception for defense, navigation, and finding mates.

Current Companions: Remoras

Who is that gliding through the water next to that shark, twisting and turning with its every move?

image of a shark swimming with several remoras attached to it

lemon shark with remoras

It’s not a baby shark. It’s not even a smaller shark species. It’s a remora, one of sharks’ closest companions.

Remoras use modified dorsal fins to stick themselves to sharks and other marine life. They help their hosts by cleaning off their parasites. They also nibble on scraps from a shark’s meal. Sharks don’t seem interested in eating remoras. In fact, some have been found stuck to the roofs of sharks’ mouths!

How Do Sharks Protect Themselves?

Imagine a shark. Is it big and scary? Not all sharks are! Many are small and vulnerable. More than half of the 500 shark species are less than 3 feet (1 meter) long. They have many important roles in ecosystems. And sharks often have to protect themselves from predators trying to eat them.

button that reads "All About Sharks"
Credits

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Image Credits:

catshark embryo in egg case, NOAA; largetooth sawfish swimming, Photo by DAVID ILIFF. License: CC BY-SA 3.0; rostrum inset, © G M MASUM BILLAH; thresher shark, Shane Gross/Science Source; lantern shark, 2018 Delroisse et al; cartilage close-up, © AMNH/J. Maisey; bull shark teeth, Reuters/Alamy; whale shark jaw, © AMNH/M. Shanley; whale shark filtering, Jonathan Bird/NatureFootage; mako shark jaw, © AMNH/M. Shanley; mako shark swimming, Andy Brandy Casagrande IV/NatureFootage;   cookie cutter teeth, Museum of New Zealand Te Papa Tongarewa; scientist examining shark, David Doubilet; bite mark on seal, BJ Stacey; Port Jackson shark jaw, © AMNH/M. Shanley; Port Jackson shark footage: NHNZ Worldwide Ltd/NatureFootage (2); lemon shark with remoras, Andy Brandy Casagrande IV/NatureFootage; honey bee hovering, Maslowski/Minden Pictures; stingray in blue water, BluePlanetArchive/Andy Murch; honey bee stinger, Ingo Arndt/Minden Pictures; stingray tail, BluePlanetArchive/Franco Bandi; electric eel, BluePlanetArchive/DR Schrichte (2); electric ray, BluePlanetArchive/Andy Murch (2); green Gabon tree frog, BluePlanetArchive/Michael S. Nolan; angel shark above seafloor, BluePlanetArchive/David B. Fleetham; brown and orange harlequin tree frog, Scubazoo/Science Source; angel shark blending with sand, BluePlanetArchive/Richard Hermann; mouse among sticks, BluePlanetArchive/ImageBroker/Wilfried Martin; lemon shark pup swimming, BluePlanetArchive/Doug Perrine; mouse looking under grasses, BluePlanetArchive/ImageBroker/Reinhard Hoelzl; lemon shark in mangrove roots, Shane Gross/Minden Pictures; puffer fish deflated, Pete Oxford/Minden Pictures; swell shark, Norbert Wu/Minden Pictures (2); puffer fish inflated, Fred Bavendam/Minden Pictures.


Video Credits:

scalloped hammerhead from below, Jonathan Bird/NatureFootage; great hammerhead hunting, Andy Brandy Casagrande IV/NatureFootage; smalltooth sand tiger shark, NOAA; mobula rays, Discovery Access; spookfish, NOAA; tiger shark swimming, Discovery Access; tiger shark snout with electroreceptors, BluePlanetArchive/John Muhilly; seals swimming, Andy Brandy Casagrande IV/NatureFootage; school of hammerheads, Simon Pierce.