Since I dive, the whale sharks amaze and fascinate me (them and manta rays) and I don't think I'm the only one! My passage to Donsol in the Philippines for plunge and make snorkeling with them was an opportunity to learn more and learn a lot of interesting things. Here is a summary of what I learned on the spot (WWF info) and sources on the internet (wikipedia, national geographic…). Find here things to know about whale sharks.

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ARTICLE GUIDELINES
1. Cut ?
2. Food ?
3. Lifetime ?
4. Where to see them?
5. Their white dots on the top?
6. NASA tracking their displacement?
7. Where does their name come from?
8. Dangerous for the man?
9. Predators?
10. Population?
11. Are they in danger? 
12. Moving? 
13. Reproduction? 
14. Do they sleep? 
15. Do they have teeth?

WHAT IS THE SIZE OF A WHALE SHARK?

Of course, their main feature is to be the biggest fish in the world (whales being mammals).

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  • Maximum size of a whale shark : 12-14 m (the size of a school bus!) and about 20 tons.
    A specimen was once "a priori" recorded at 18 m in 1999, but there is no evidence and it never happened again.
  • Observed average size : 6 to 10 m
  • Size at birth : 50 to 80 cm
  • Adult size : about 2 years
  • Females are bigger than the males.
  • His mouth done between 1 and 1.5 m
Size, Food, Lifetime, Or, White points, The NASA, Name, Dangerous, predators, Number, Threat, Speed, Reproduction, Sleep, teeth

WHAT DO WHALE SHARKS EAT?

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  • Whale sharks feed by filtering the water they absorb. They open their giant mouths, filters the nutrients they need and let the water come out.
  • They feed mostly plankton : near a ton a day !
  • But also microscopic animals like the krill (tiny shrimp), shellfish, Pisces, octopus, sardines, anchovy
Size, Food, Lifetime, Or, White points, The NASA, Name, Dangerous, predators, Number, Threat, Speed, Reproduction, Sleep, teeth

WHAT IS THE LIFETIME OF A WHALE SHARK?

  • Scientists still lack a lot of information, but they currently believe that a whale shark could live up to 100-150 years
  • The older specimen identified so far had 70 years
Size, Food, Lifetime, Or, White points, The NASA, Name, Dangerous, predators, Number, Threat, Speed, Reproduction, Sleep, teeth

WHERE CAN WE SEE WHALE SHARKS?

  • Whale sharks are constantly migrating to reach prolific regions for their food, sometimes over enormous distances (thousands of kilometers).
  • We only find them in the tropical areas between latitudes 30 ° N and 35 ° S :

carte-zone-requin-baleine

The most famous places to see whale sharks:

  • Peaceful : Galapagos (Ecuador), Socorro (Mexico), Isla Coco (Costa Rica), La Paz (Mexico, Sea of Cortez), Ningaloo and Christmas Island (Australia)
  • Asia : Donsol and Oslob (Philippines), Richelieu rock (Thailand), Cenderawasih bay (Indonesia)
  • Indian : Nosy Be (Madagascar), Tofo (Mozambique), Sodwana (South Africa), Ari atoll (Maldives), Seychelle
  • Atlantic : Isla Contoy (between Isla Holbox and Isla Mujeres in Mexico), Utila (Honduras), Gladden split (Belize)

carte-ou-voir-des-requins-baleines

The top 12 of the best destinations to see whale sharks

Size, Food, Lifetime, Or, White points, The NASA, Name, Dangerous, predators, Number, Threat, Speed, Reproduction, Sleep, teeth

WHAT ARE WHITE POINTS OF WHALE SHARKS

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  • The arrangement of white dots and lines that cover the top of their bodies (forming a kind of checkerboard), are unique to each animal, the making all unique.
  • They are like theirs borrows digitallyit is by this means that scientists are trying to identify them.
Size, Food, Lifetime, Or, White points, The NASA, Name, Dangerous, predators, Number, Threat, Speed, Reproduction, Sleep, teeth

NASA FOLLOWING WHITE SHARKS!

Yes, yes, you read correctly, NASA helps scientists track displacement whale sharks!

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  • The marine biologist Jason Holmberg was the first to understand the uniqueness of the arrangement of white dots and lines covering the top of whale sharks (a kind of checkerboard) and the possibility of using it as fingerprint to identify them
  • NASA, it has developed years ago a algorithm to map and identify star constellations.
  • The checkerboard of the whale sharks being unique (in the same way as the location of the stars),  the algorithm used by NASA has been modified so as to compare, no longer starry skies, but "checkers" of whale sharks!
  • Today, scientists and tourists can implement in an online database (Www.whaleshark.org) the picture of a whale shark accompanied by place and some dated.
  • The algorithm is going compare thousands of photos from its database (more than 30,000 in 2017) and see if he finds a match
  • Currently over 8000 individuals have been identified
  • This is a gold mine of information on the movement of whale sharks

FYI: Several cases have allowed scientists to discover that whale sharks could move over thousands of kilometers in a very short time (3000 to 5000 km in a few months!).

Size, Food, Lifetime, Or, White points, The NASA, Name, Dangerous, predators, Number, Threat, Speed, Reproduction, Sleep, teeth

WHY ARE WE CALLED WHALE SHARK?

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  • Whale sharks belong to the class of sharks (chondrichthyans, just like rays) because of their skeleton, made entirely of cartilage.
  • The addition of the word whale "Comes, unsurprisingly, from their cut and the comparison with the whales.
Size, Food, Lifetime, Or, White points, The NASA, Name, Dangerous, predators, Number, Threat, Speed, Reproduction, Sleep, teethd

ARE WHALE SHARKS DANGEROUS TO MAN?

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  • Even if by the size of his mouth (1 to 1.5 m), they could swallow us easily, the whale shark does not represent any danger to humans !
  • They are the most pacifist sharks, see some fish !! No whale shark attacks have ever been reported.
  • There is really than getting a shot from his big cock which could be dangerous for us!
Size, Food, Lifetime, Or, White points, The NASA, Name, Dangerous, predators, Number, Threat, Speed, Reproduction, Sleep, teeth

WHAT ARE THE PREDATORS OF WHALE SHARKS?

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  • The human being is their main predator..., mainly because of fishing for the trade of his fins (Like the majority of other sharks elsewhere, thank you Chinese ...).
  • The only other known predators are the killer whales and some opportunistic sharks (like the great white shark or the blue shark) that attack young whale sharks.
Size, Food, Lifetime, Or, White points, The NASA, Name, Dangerous, predators, Number, Threat, Speed, Reproduction, Sleep, teeth

WHAT IS THE POPULATION OF WHALE SHARKS?

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  • Because of their disparity and permanent geographical mobility, accurate counting is very hard! I searched everywhere, I did not find any official figure !!
  • Each migratory area tries to identify them on their perimeter
  • What we do know is that their numbers are falling year after year in each zone ...
Size, Food, Lifetime, Or, White points, The NASA, Name, Dangerous, predators, Number, Threat, Speed, Reproduction, Sleep, teeth

ARE WHALE SHARKS AT RISK?

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  • Yes, they are in dangerdeclared threatened since 1990.
  • Man is the main cause the decline in the number of whale sharks:
  • Threats to sharks included : dwindling habitat, marine pollution, collision with boats, fishing net, fierce boats or snorkelers in some areas that do not respect eco-tourism ...
  • The biggest threat, however, remains fishing for the fin trade., used for the Chinese market (medicine and soup).
Size, Food, Lifetime, Or, White points, The NASA, Name, Dangerous, predators, Number, Threat, Speed, Reproduction, Sleep, teeth

HOW DO WHALE SHARKS MOVE?

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  • They use all their body, not just their tail like most fish
  • It's a fish very slow, maximum: 5 km / h
  • Even slow, they can to travel thousands of kilometers
  • Even though they are more often near the surface, whale sharks can descend to depths of 1500-2000 m
Size, Food, Lifetime, Or, White points, The NASA, Name, Dangerous, predators, Number, Threat, Speed, Reproduction, Sleep, teeth

How do whale sharks reproduce?

Their reproduction is one of the most unknown subjects.

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  • They are oviparous (leggs are incubated and hatch in the belly of the female)
  • Nobody really knows where they mate and where they give birth
  • They reach their sexual majority around 30 years
  • We think they can have up to 300 eggs per litter and that they give birth only a few times in all their lives.
Size, Food, Lifetime, Or, White points, The NASA, Name, Dangerous, predators, Number, Threat, Speed, Reproduction, Sleep, teeth

Do whale sharks sleep?

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  • NoLike the majority of sharks, whale sharks must constantly to be in motion to be able to breathe.
  • Whale sharks must constantly to be in motion so that the water goes through their gills and the feeds oxygen.
  • They never sleep, but they are resting !
  • In addition to the normal "active" mode, they have a "passive" mode ("Sleep swimming" in English) during which some parts of their brains are "paused"but they still continue to swim.
Size, Food, Lifetime, Or, White points, The NASA, Name, Dangerous, predators, Number, Threat, Speed, Reproduction, Sleep, teeth

DO WHALE SHARKS HAVE TEETH?

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  • Yes, they have 300-350 rows of teeth according to their size, they do not use to eat!
  • Why do they have them? Nobody has yet come up with a tangible answer !!

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