Whale sharks may not be the first species that comes to mind when you think of a shark. They are huge, graceful, and beautifully-colored. They are not really voracious predators, but feed on some of the tiniest creatures in the ocean. Below are some fun facts about whale sharks.
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One of the most notable facts about whale sharks is that they are the world's largest fish
. At a maximum length of about 65 feet and weight of 75,000 pounds, a whale shark's size rivals that of large whales
2. Whale sharks feed on some of the ocean's tiniest creatures.
Even though they are huge, whale sharks feed on tiny plankton
, small fish
, and crustaceans
. They feed by gulping mouthfuls of water and forcing that water through their gills. Prey
gets trapped in dermal denticles
and a rake-like structure called the pharynx. This amazing creature can filter over 1,500 gallons of water an hour.
Whale sharks, and other elasmobranchs
such as skates
and rays are cartilaginous fish. Instead of having a skeleton made of bone, they have a skeleton made of cartilage
, a tough, flexible tissue. Since cartilage doesn't preserve as well as bone, much of what we know about early sharks comes from teeth, rather than fossilized bone.
4. Female whale sharks are larger than males.
Whale shark females are usually larger than males. This is true for most other sharks, and for baleen whales
, another type of animal that is large but eats small organisms. How can one tell male and female whale sharks apart? Like other shark species, males have a pair of appendages called claspers
which are used to grasp the female and transfer sperm when mating. Females do not have claspers.
5. Whale sharks are found in warm waters around the world.The whale shark is a widespread species - they are found in warmer waters, but in several oceans - the Atlantic, Pacific and Indian.
6. Whale sharks can be studied by identifying individuals.
Whale sharks have a beautiful coloration pattern, with a bluish-gray to brown back, and a white underside. This is an example of countershading
, and may be used for camouflage. They also have light vertical and horizontal striping on their sides and back, with white or cream-colored spots. These also may be used for camouflage. Each whale shark has a unique pattern of spots and stripes, enabling researchers to use photo-identification to study them. By taking photos of whale sharks (similar to the way whales
are studied), scientists can catalog individuals based on their pattern and match subsequent sightings of whale sharks to the catalog.
7. Whale sharks are migratory.
The movement of whale sharks was poorly understood up until about 10 years ago, when developments in tagging technology allowed scientists to tag whale sharks and observe their migrations. We know now that whale sharks are capable of undertaking migrations thousands of miles long - one tagged shark traveled 8,000 miles over 37 months (see more about tagging studies on the IUCN Red List site here
, and more on tag types here
.) Mexico appears to be a popular spot for the sharks - in 2009, a "swarm" of over 400 whale sharks was seen
off Mexico's Yucatan Peninsula
8. You could swim with a whale shark.
Because of their gentle nature, excursions involving swimming, snorkeling and diving
with whale sharks have developed in some areas such as Mexico
, and the Philippines
9. Whale sharks may live for over 100 years.
There is still a lot to learn about the life cycle of a whale shark. Here is what we do know. Whale sharks are ovoviviparous
- females lay eggs, but they develop inside her body. A recent study
showed that it is possible for whale sharks to have several litters from one mating. Whale shark pups are about 2 feet long when born. Scientists are not sure how long whale sharks live, but based on their large size and their age at first reproduction (around 30 years old for males) it is thought that whale sharks may live at least 100-150 years.
10. Whale shark populations are vulnerable.
The whale shark is listed as vulnerable
on the IUCN Red List. It is still hunted in some areas, and its fins can be valuable in the shark finning
trade. Since they are slow to grow and reproduce, populations may not recover quickly if this species is overfished