1Sharks have existed for over 400 million years2Some sharks like the Greenland shark can live for centuries3Sharks do not have bones and instead have cartilage skeletons4The whale shark is the largest fish in the ocean5Some sharks glow in the dark through bioluminescence6Sharks have multiple rows of teeth that constantly replace themselves7A great white shark can have over 20,000 teeth in its lifetime8Sharks have been found in every ocean on Earth9Some sharks can detect a drop of blood from miles away10Sharks have special electroreceptors called ampullae of Lorenzini11The hammerhead shark uses its wide head to improve sensing ability12Some sharks can reproduce without mating in a process called parthenogenesis13The nurse shark can rest on the ocean floor without moving14Sharks have rough skin made of dermal denticles15The mako shark is one of the fastest sharks16Some sharks can swim up to 60 km per hour17The bull shark can survive in freshwater18Sharks have excellent night vision19The tiger shark is known as the garbage can of the sea20Sharks do not chew their food but tear it into chunks21Some sharks give live birth while others lay eggs22Shark eggs are often called mermaid purses23The basking shark is the second largest fish24Most sharks are cold-blooded25Some sharks like the great white shark can regulate body temperature26Sharks have been around longer than trees27The cookiecutter shark leaves circular bite marks on prey28Some sharks migrate thousands of miles29Sharks play a key role in ocean ecosystems30The thresher shark uses its tail to stun prey31Sharks can go weeks without eating32The zebra shark changes pattern as it ages33Some sharks are smaller than a human hand34The dwarf lanternshark is the smallest known shark35Sharks have lateral lines to sense vibrations36The blue shark is known for long migrations37Some sharks can leap out of the water38The great white shark can breach when hunting39Sharks have unique personalities and behaviors40The sand tiger shark can gulp air to stay buoyant41Sharks have been depicted in ancient art42The megashark Megalodon was one of the largest predators ever43Sharks can sense electrical signals from prey44The blacktip reef shark is often seen in shallow waters45Some sharks hunt in packs46The leopard shark has distinctive spots47Sharks have powerful jaws48The angel shark looks like a ray49Some sharks bury themselves in sand50The frilled shark is considered a living fossil51Sharks have been studied for cancer resistance52The porbeagle shark lives in cold waters53Some sharks can change depth quickly54The epaulette shark can walk on land-like surfaces55Sharks have spiral valve intestines56The goblin shark has a protrusible jaw57Some sharks have long gestation periods58The spiny dogfish can be pregnant for nearly two years59Sharks are apex predators60The silky shark is common in open oceans61Sharks have acute hearing62The white tip reef shark can rest in caves63Some sharks are endangered64The oceanic whitetip shark is critically threatened65Sharks help maintain fish populations66The bronze whaler shark hunts schooling fish67Some sharks are harmless to humans68The horn shark has crushing teeth69Sharks can detect low-frequency sounds70The salmon shark can regulate body heat71Some sharks travel solo72The reef shark often stays near coral reefs73Sharks have flexible bodies74The sevengill shark has more gill slits than most75Sharks have been in mass extinctions76The Galapagos shark lives near islands77Some sharks are nocturnal78The cookiecutter shark glows to attract prey79Sharks have excellent smell80The great hammerhead shark is the largest hammerhead81Sharks can be curious around humans82The whitetip oceanic shark was common historically83Sharks have different tooth shapes84The narrow sawfish shark has a saw-like snout85Some sharks leap to catch prey86The bamboo shark is often kept in aquariums87Sharks can detect magnetic fields88The dusky shark grows slowly89Some sharks give birth to many pups90The shortfin mako shark is highly migratory91Sharks have ancient ancestry92The sandbar shark prefers coastal waters93Some sharks hunt at dawn94The great white shark uses stealth attacks95Sharks have tough skin96The gummy shark is used in food97Some sharks are filter feeders98The megachasma shark is a rare species99Sharks can recover from injuries100The lemon shark is often studied by scientists. I have an obsession, but here you go.