Sharks: they rule 70 percent of the world | Photo: Elias Levy/Creative Commons

Sharks are one of the oldest living species on planet Earth. They've survived the most severe mass extinction events, and they rule 70 percent of the world.

Ready to learn things you didn't know about sharks? You will be amazed by how special sharks really are.

Sharks are fast and intelligent, and they can only fear humans. Yes, we are their only predators. But their bodies are authentic underwater machines.

Their smell, sight, hearing, mouth, skin, electroreception, and lateral lines are complex systems built to survive and hunt in multiple environments.

In the past, sharks were known as "sea dogs." Today, sharks are the masters of the water world.

Respect them, and learn everything you need to know about sharks:

1. The largest shark ever found was a whale shark measuring 41.5 feet (12.6 meters);

2. The smallest shark is the dwarf lantern shark; it measures six inches (15 centimeters);

3. The most common shark is the ocean whitetip;

4. The fastest shark is the short-fin mako shark, and it can swim up to 65 miles per hour (104.6 kilometers per hour);

5. Sharks detect a blood drop in an Olympic pool;

6. A shark bite generates up to 40,000 pounds (18,143 kilograms) of pressure per square inch;

7. The great white shark eats 22 times more than an average human;

8. Sharks are not mammals; sharks are fishes;

9. There are roughly 500 species of sharks;

10. Sharks are between 425 and 455 million years old;

11. Sharks are older than dinosaurs;

12. The oldest shark teeth were found in Europe;

13. Sharks were in the 5 percent of the species that survived five major mass extinction events;

14. Sharks use their electro-sensors (Ampullae of Lorenzini) to locate prey and navigate the oceans;

15. Sharks can open their mouth to nearly 180 degrees;

16. Sharks have rows of teeth;

17. A shark may produce roughly 6,000 teeth each year;

Sharks: only 10 out of 500 species of sharks have been involved in incidents with humans | Photo: Shutterstock

18. Sharks don't have bones, only cartilage;

19. Bull sharks can live in both salt and fresh water;

20. Salmon sharks regulate their body temperature to live in the Alaskan waters;

21. Shark mating can involve biting;

22. Reproductive cycles for sharks can last two years;

23. Some female sharks can store sperm for up to a year;

24. Shark sight works similarly to that of humans;

25. Sharks see in dark or murky water up to ten times greater than humans in clear water;

26. Sharks get cancer;

27. Half the world's shark fin trade goes through Hong Kong;

28. Commercial fishing kills 100 million sharks each year;

29. Shark fin soup has been a Chinese specialty since the Ming Dynasty;

30. It hasn't been scientifically proven that shark liver oil or its components are effective against cancer;

31. Only 10 out of 500 species of sharks have been involved in incidents with humans;

32. Sharks hunt in the evening and night;

33. The average life span of most shark species is 20 years;

34. The spiny dogfish shark can live more than 100 years;

35. Sharks sleep and rest with their eyes open;

36. Sharks live in waters from 7,000 feet to 10,000 feet (2,133 to 3,048 meters);

37. Sharks have rough skin;

38. Blue sharks like cooler waters;

39. Some shark species drown if they stop moving;

40. Your odds of getting attacked and killed by a shark are 1 in 3,750,000;

41. There's intrauterine cannibalism in the shark world;

42. Sharks prefer to hunt solo;

43. Galeophobia is the excessive fear of sharks;

44. Sharks have a 360-degree vision;

45. Sharks only have inner ears;

46. Sharks have seven senses;

47. Great white sharks jump 10 feet (three meters) in the air;

48. Sharks can be found in all oceans of the world;

49. The majority of sharks are ovoviviparous;

50. Sharks are part of Hawaiian mythology;

51. The great white shark has been protected in South Africa since 1991;

52. Sharks move water over their gills to breathe, but not all species need to actually swim or move to get oxygen - it's the case of angel and nurse sharks;

53. The longest-living vertebrate animal in the world is the Greenland shark, also known as the gurry shark. Researchers from the University of Copenhagen combined the apex predator's yearly growth rate with the carbon-14 dating of his eye lenses and concluded that the Greenland shark could live for more than 400 years. It swims in the cold waters of the Arctic and North Atlantic oceans;

Take a look at the most shark-infested waters in the world. Learn how to survive a shark attack.

Top Stories

The number of seaside communities whose beaches are losing sand is growing exponentially. What are the explanations for coastal erosion, and what can be done to mitigate its devastating impact?

Welcome to the Drake Passage, the world's most dangerous sea route, home to 65-foot-plus waves. Here's why the 620-mile stretch between Cape Horn and Antarctica is treacherous and has become the ultimate extreme sailing adventure.

There is a place on Earth where the difference between low and high tide reaches 53.6 feet (16.3 meters). It's the Bay of Fundy in Canada. You've got to see it to believe it.

A fourth global coral bleaching wave is sweeping the world's oceans.