Dolphins: incredibly intelligent, excellent swimmers, and highly social individuals | Photo: Shutterstock

They're funny, cute, athletic, and extremely friendly. Welcome to the extraordinary world of dolphins.

Dolphins are aquatic mammals that have always fascinated humans. Kids and adults have learned to respect the marine creature that sometimes behaves like humans.

Scientists have concluded that dolphins are incredibly smart living beings and have become super-fast swimmers thanks to their anatomy.

Let's take a look at the most interesting facts about dolphins:

1. Dolphins evolved from a four-legged terrestrial animal that started spending more time in the water around 50 million years ago;

2. The name "dolphin" comes from the Greek words "delphis" and "delphus," meaning "fish with a womb";

3. There are around 40 different species of dolphins swimming in the oceans of the world;

4. Dolphins range in size from 5.6 feet (1.7 meters) to 31 feet (9.4 meters) long and weigh between 110 pounds (50 kilograms) and 10 tonnes, depending on the type of animal and species;

5. The killer whale is the largest member of the oceanic dolphin family;

6. The most common species - the bottlenose dolphin - inhabits all regions of the planet except for the Antarctic and Arctic oceans;

7. The differences between dolphins and porpoises can be found in their body shapes, fins, and faces;

8. Dolphins live in relatively shallow waters, but they can dive up to 900 feet (274 meters);

9. Dolphins are piscivores and eat around 35 pounds (15.8 kilograms) of fish every day, including squid and crustaceans;

10. Dolphins don't drink water because they get it from the food they eat;

Dolphins: they're talented surfers | Photo: Shutterstock

11. Although dolphins have teeth, they swallow food without chewing it;

12. Dolphins have two stomachs - one for storing food and another one for digestion;

13. Dolphins have a skeleton with light, highly flexible, yet weaker bones compared with land animals;

14. Dolphins are "equipped" with highly effective healing processes, which means that they don't hemorrhage to death easily;

15. Dolphins are believed to have the longest memory in the animal kingdom;

16. Dolphins use their echolocation/sonar for navigating through the water and obstacles and hunting prey;

17. Dolphins' hearing system is so sophisticated and advanced that even a blind individual can survive;

18. Dolphins have no sense of smell and do not have a good sense of taste;

19. Dolphins can use their noses to kill sharks;

20. Dolphins have smooth skin to reduce drag while swimming - their outer skin layer can regenerate in only two hours;

Dolphins: there are around 3,000 individuals in captivity worldwide | Photo: Walter/Creative Commons

21. Although dolphins have lungs and breathe like humans, they can't live on land because they become dehydrated and overheat out of the water;

22. Dolphins sleep eight hours per day and spend the rest of the day swimming;

23. Dolphins typically resurface to breathe three to five times per minute, but they can hold their breath for up to 15 minutes;

24. Dolphins sleep with only one brain hemisphere at a time in slow-wave sleep to maintain enough consciousness to breathe and to watch for possible predators;

25. During the gestation period, female dolphins carry one baby at a time, but sometimes they may deliver twins;

26. After giving birth, female dolphins carry their calves for between 11 and 18 months;

27. Dolphin mothers feed their babies with extremely rich and fatty milk;

28. The average life expectancy of a dolphin is 25 years, but they can live up to 50;

29. Dolphins are highly intelligent marine creatures - they can learn, play, socialize, and grieve just like humans;

30. Dolphins are altruistic individuals and tend to stay with ill or injured individuals for prolonged periods of time;

31. Dolphins communicate through whistles, clicks, and other nonverbal forms of communication;

32. Dolphins call out to each other by their names;

33. Dolphins usually travel in pods of up to 1,000 individuals;

34. Dolphins are not monogamous;

35. Dolphins usually swim at between 3 and 8 miles per hour (4.8-12.8 kilometers per hour), but their top speed is around 20 miles per hour (32 kilometers per hour);

36. A dolphin can travel up to 60 miles (96.5 kilometers) per day;

37. Dolphins not only know, but they also enjoy catching and surfing waves like humans do;

38. Scientists have not yet understood why dolphins jump out of the water - some of them leap over 20 feet (six meters) in the air;

39. Dolphins have few enemies - only the great white shark, tiger shark, dusky shark, and bull shark can be considered serious threats;

40. Dolphins only bite if they're furious, angry, frustrated, anxious, or afraid;

Dolphins: they are trained by the military for search and recovery operations | Photo: US Navy/Creative Commons

41. Dolphins are trained by military forces to spot mines and find lost humans;

42. Japan, Peru, the Solomon Islands, and the Faroe Islands are known for killing dolphins for human consumption;

43. The coat of arms of Anguilla and Romania feature dolphins;

44. India, Hungary, Costa Rica, and Chile have declared dolphins "non-human persons," meaning that they can't be captured and used for entertainment purposes, for example, in dolphinariums;

45. The desert city of Petra, established as early as 312 BC in Jordan, has images of dolphins carved in the rocks;

46. A group of dolphins is named a "school." Female dolphins are "cows," male dolphins are "bulls," and juveniles are "calves";

47. According to several animal welfare organizations, there are around 3,000 dolphins in captivity worldwide;

48. The most famous movies about dolphins are "Flipper," "The Day of the Dolphin," "Zeus and Roxanne," "The Cove," and "Dolphin Tale";

49. In 2010, director Greg Huglin released a 20-minute film called "Surfing Dolphins," featuring some of the world's finest wave-riding performers;

50. Nana and Nellie are the longest-living dolphins on record. They lived 42 and 61 years, respectively;

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