Cracking the mysteries of the elusive, majestic whale shark In this 2017 photo provided by Simon Pierce, Jonathan Green checks on a fin-mounted satellite tag on a whale shark in the Galapagos Islands area of Ecuador. (simonjpierce.com via AP)
Cracking the mysteries of the elusive, majestic whale shark
Lexile

It's the biggest shark and the biggest fish in the sea. It is often found roaming in warm waters around the globe. Typically, it has its huge mouth agape in search of dinner.

Yet despite its hulking appearance, the whale shark has only tiny, almost useless teeth. It is sometimes so docile that entire boatloads of people can swim alongside the enigmatic, spotted beast. It's also one of the least understood animals in the oceans.

A group of scientists spent several weeks diving with whale sharks in the Galapagos Islands last summer and fall. They were attempting to solve some of the most enduring mysteries. They tried some never-before-used techniques on the species in the wild. For instance, they took blood samples and did ultrasound exams, all while swimming furiously beside them underwater.

Here's what's known about these massive marine animals and what scientists are still trying to find out:

WHALE OR SHARK?

While they are comparable in size to whales, whale sharks are sharks. They typically grow to be bigger than a double-decker bus. They grow to 20 to 52 feet and can weigh more than 20 tons. But they are filter feeders - the enormous whale sharks are dangerous only to the plankton, fish eggs and tiny fish they chomp on.

The gentle giants aren't particularly fast when compared to other sharks. But a simple wave of their tail propels them through the water faster than any human could ever swim. They have broad, flat heads and their entire dark-blue bodies are covered in dots that act as camouflage underwater.

They have been overhunted by fishermen for years. Now whale sharks are endangered and at risk of extinction.

HANGOUT SPOTS.

Whale sharks prefer warm waters and are often found feeding at locations around the world including Australia, the Philippines, Mexico and even in the oil fields off the coast of Qatar.

Hundreds of whale sharks — mostly young males — congregate in these areas at certain times of the year to scoop up fish eggs. It's unknown where adult females are feeding then.

The vastness of the ocean usually makes the shy animals hard to find — Jacques Cousteau only ever saw two in his decades of sea exploration.

TRACKING WHALE SHARKS.

Marine biologists have been tagging whale sharks in recent years to track their movements. Others are trying to answer questions about their life and reproductive cycles. Only one pregnant whale shark has ever been found: In 1995, a dead whale shark was found off the coast of Taiwan with 300 embryos inside, all at different stages of development.

"The million-dollar questions are where are they mating, hunting and where do their young live?" said Jonathan Green, director of the Galapagos Whale Shark Project.

An international database was launched to identify as many whale sharks as possible through their distinctive dot pattern. Each shark has a unique configuration of dots that act like a fingerprint. More than 8,000 sharks have been logged so far. Because scientists can only afford to spend a few weeks in the Galapagos each year, they depend on photos taken by visiting divers to figure out what the whale sharks are up to. So far, none of the sharks spotted in the Galapagos has been seen anywhere else.


RESULTS.

Because of the difficulty of conducting a medical exam on a free-swimming whale shark, researchers only obtained two blood samples, which haven't yet been tested. The ultrasound exams were inconclusive and Green said more powerful machines are needed. Most ultrasound machines for animals are intended for abdominal walls that are 1 to 2 inches thick — but a whale shark's abdominal wall is about 8 inches.

"When we first started studying these large animals, nobody knew how to go about it," Green said. "Now that we have better technology and more experience, we will hopefully be able to answer some of the fundamental questions soon."

Besides blood and ultrasound tests, scientists successfully tagged seven sharks. While not a large number, it's important since so few whale sharks are tracked. The pressure of deep water can cause tags to drop off if the sharks dive below 2,000 meters (6,561 feet), which the animals often do if they're traveling long distances or possibly giving birth. But any migratory data the scientists collect when sharks stay at shallower depths can help build a picture of the sharks' life cycle.

Green and colleagues are planning further expeditions to the Galapagos later this year to continue their research, including more blood samples and satellite tagging.

"When you have so few data points, every single shark is important," said Robert Hueter, director of the Center for Shark Research at Mote Marine Laboratory in Florida. He was not part of the Galapagos research. "These aren't like goldfish where you can get sample sizes of hundreds at a time."

WHY IT MATTERS.

In the last 75 years, the vast majority of whale sharks have been hunted by people for food and their numbers are still dropping, said Simon Pierce, chief scientist at the Marine Megafauna Foundation .

Some biologists worry climate change could hurt the sharks by reducing their food supply: rising ocean temperatures could mean less plankton.

"If we do the things that are necessary to conserve the whale sharks, we'll be conserving the ocean itself," said Simon Thorrold of the Woods Hole Oceanographic Institute in Massachusetts.

For Green, who heads the Galapagos project, it's more personal. "Even after years of diving with whale sharks, I still get goose bumps every time I see that huge blue shadow in the water. It's an incredibly emotional experience."

Filed Under:  
Assigned 120 times
CRITICAL THINKING QUESTION
How can a shark be a whale?
Write your answers in the comments section below


COMMENTS (23)
  • KylieF-dec
    3/12/2018 - 11:10 a.m.

    A shark cannot be whale. They are two entirely different species. The only to a shark being a whale is a whale shark. While some may think that it is a combination of a whale and a shark. It is unfortunately, just a breed of shark.

  • TaylorH-dec1
    3/12/2018 - 11:11 a.m.

    A shark cannot be a whale, they are two different species. For example, a shark doesn’t just swim with their mouth open to catch food, a shark chases it’s food. So a shark cannot be a whale except for the whale shark.

  • JadeR-del
    3/13/2018 - 04:06 p.m.

    A summary of the article is that there are many questions about the big, beautiful and mysterious being that is the whale shark. Some questions. Some mysteries are is the whale shark a fish or shark? because in name is says shark but the whale shark doesn't attack in a vicious manner. it just swims straight and opens its very large mouth sucking in little fish and other small sea creatures into its mouth. This is known as filter feeding, the whale shark is a type of shark. the filter feeding kind. They are more gentle.
    But this article covers some other big questions many people ask about whale sharks.

  • ZofiaT-del
    3/13/2018 - 04:06 p.m.

    This article is about how scientists are trying to figuring out the mysteries of the whale sharks. They have found out that whale sharks are actually sharks. Because whale sharks are massive, they cannot be caught to observe, but they can be tracked. Scientists now have figured out how to track them. They see their mating areas now to save the population. Now that we have all this information about the population, we can help save them.

  • SophiaD-del1
    3/13/2018 - 04:13 p.m.

    There are many questions about the elusive whale shark! Scientist have been trying too find the breeding grounds, offspring's homes, and more about this whale shark. It is a shark that is actually endangered and is also a gentle giant.

  • SarahT-del
    3/13/2018 - 05:07 p.m.

    Last summer, a group of scientists were swimming with whale sharks. This is a major thing because for over 75 years theres creatures were hunted for and killed. Comparing the sizes, they found out it was a shark. Theyre found in warm waters around Mexico or Australia.

  • EvanC-del
    3/13/2018 - 06:02 p.m.

    A shark can be whale because of its size. I think sharks are beautiful looking animals even though they do eat humans. They are very interesting specifically their skin and teeth. This was a very interesting topic and I hope to read about something like this again.

  • JasminderK-del
    3/13/2018 - 06:49 p.m.

    This article is about whale sharks, it teaches us about them and how they have been hunted for 75 years and how scientists are trying to learn more about them.

  • AkshayB-del
    3/13/2018 - 08:23 p.m.

    This article is about figuring out if this shark whale is actually really big. A group of scientists spent several weeks diving with whale sharks in the Galapagos Islands last summer and fall. They tried some never-before-used techniques on the species in the wild. For instance, they took blood samples and did ultrasound exams, all while swimming furiously beside them underwater. While they are comparable in size to whales, whale sharks are sharks. They typically grow to be bigger than a double-decker bus. They grow to 20 to 52 feet and can weigh more than 20 tons.

  • ChloeT-del
    3/13/2018 - 08:36 p.m.

    This article is about a whale shark. A group of scientists were trying to solve the mysteries of the whale sharks. They did ultrasound exams and took blood samples from the whale sharks while swimming next to them underwater. They were being hunted by fisherman and now they are close to extinction. They are usually in warm waters and can be found in the Philippines, Australia, off the coast of Qatar and Mexico feeding. Marine biologists have been studying the whale sharks to examine how they live and to answer the questions they've wanted to get the answers to.

Take the Quiz Leave a comment
ADVERTISEMENT