The world's largest fish is very mysterious, and endangered

Don't think the name is a joke. They are not whales. They are fearsome creatures.

They are the biggest fish species on the planet. As long as a city bus, whale sharks can grow as long as they want. There areWhale sharks that eat shrimp, plants, and beyond.

This large species, which is listed as being in danger by the International Union for the Preservation of Nature, is a mystery to biologists.

According to the vice president of the Georgia Aquarium, whale sharks challenge everything we know about sharks, and he loves it.

Mysterious creatures

The way in which whale sharks give birth is not well understood. Female whale sharks are said to make their eggs, hatch inside them, and then release live babies into the water. Researchers have yet to witness a whale shark mate or give birth. Fishermen killed and cut open a pregnant female shark in Taiwan in 1995. There were some 300 dead baby whale sharks inside.

The shark's pups were frozen after fishermen realized they had never seen a whale shark with hundreds of pups.

The team decided to do a genetic analysis on 10 percent of the pups to see if they are related to one another. They discovered that all the pups had the same father and that whale sharks could mate once, store the sperm, and eventually fertilize their own eggs.

It's difficult to know what a whale shark's life is like. They are likely to live for over a century. It's difficult to track a single animal and how it migrates over time.

It's impossible to track one animal for its entire life.

The number of rings on the fish's bones is used to determine their age. Georgia Aquarium's Dove said that whale sharks don't have hard bones like other fish and calculating their age becomes difficult.

Whale sharks spend considerable time on the surface of the water and easily get hit by ships. Scientists say it's one of the reasons for their population decline. Credit: AvigatorPhotographer / Getty Images

Endangered creatures

It's important to know how whale sharks migrate. An estimated 50 percent of whale sharks have been lost over the last 75 years according to a researcher.

Dove said that fishing is the number one threat to whale sharks despite attempts to protect them. A whale shark is caught by people in small villages. He said that it was enough to feed their village for a while.

Dove said that the next threat is ships colliding with whale sharks. Commercial fishing ships can easily hit whale sharks on the sea surface. whale sharks sink after they've been killed, unlike whales who float after they die. He said that commercial shipping can be silent killers.

The whale shark population is in danger of being threatened by climate change. According to Araujo, plankton is sensitive to temperature and acidity in the ocean, and whale sharks will redistribute depending on how their prey changes. They may not be able to succeed in new areas. He said that it would be over long time scales.

Plastic pollution is a threat to their survival. The filter feeders of the whale sharks are able to make a living by eating the bounty of water. Dove said they couldn't differentiate between plankton and plastic. He said they don't know what impact this plastic has on their health.

We still don't know a lot about whale sharks. Dove said that we need to know where the animals are born, where they breed, and where their babies go. Dove said that whale sharks have been doing their thing in the ocean since the tyrannosaurus rex stomped around.