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 body is a complete underwater machine. Their smell, sight, hearing, mouth, skin, electroreception and lateral line is a complex system 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 41.50 feet
2. The smallest shark is the dwarf lantern shark; it measures 6 inches
2. The most common shark is the ocean whitetip
3. The fastest shark is the shortfin mako shark, and it can swim up to 65 mph
4. Sharks detect a blood drop in an Olympic pool
5. A shark bite generates up to 40,000 pounds of pressure per square inch
6. The great white shark eats 22 times more than an average human
7. Sharks are not mammals; sharks are fishes
8. There are roughly 500 species of sharks
9. Sharks are between 425 and 455 million years old
10. Sharks are older than dinosaurs
11. The oldest shark teeth were found in Europe
12. Sharks were in the 5 percent of the species that survived five major mass extinction events
13. Sharks use their electro-sensors (Ampullae of Lorenzini) to locate prey and navigate the oceans
14. Sharks can open their mouth to nearly 180 degrees
15. Sharks have rows of teeth
16. A shark may produce roughly 6,000 teeth each year
17. Sharks don't have bones, only cartilage
18. Bull sharks can live in both salt and fresh water
19. Salmon sharks regulate their body temperature to live in the Alaskan waters
20. Shark mating can involve biting
21. Reproductive cycles for sharks can last two years
22. Some female sharks can store sperm for up to a year
23. Shark sight works similarly to that of humans
24. Sharks see in dark or murky water up to ten times greater than humans in clear water
25. Sharks get cancer
26. Half the world's shark fin trade in goes through Hong Kong
27. Commercial fishing kills 100 million sharks each year
28. Shark fin soup is a Chinese specialty since the Ming Dynasty
29. It hasn't been scientifically proven that shark liver oil or its components are effective against cancer
30. Only 10 out of 500 species of sharks have been involved in incidents with humans
31. Sharks hunt in the evening and night
32. The average life span of most shark species is 20 years
33. The spiny dogfish shark can live more than 100 years
34. Sharks sleep with their eyes open
35. Sharks live in the waters from 7,000 feet to 10,000 feet
36. Shark have a rough skin
37. Blue sharks like cooler waters
38. Some shark species drown if they stop moving
39. Your odds of getting attacked and killed by a shark are 1 in 3,750,000
40. There's intrauterine cannibalism in the shark world
41. Sharks prefer to hunt solo
42. Galeophobia is the excessive fear of sharks
43. Sharks have a 360-degree vision
44. Sharks only have inner ears
45. Sharks have seven senses
46. Great white sharks jump 10 feet in the air
47. Sharks are in all oceans
48. The majority of sharks are ovoviviparous
49. Sharks are part of the Hawaiian mythology
50. The great white shark is protected in South Africa since 1991

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