Seeing a basking shark swimming through the ocean with its incredible, gaping mouth must be an odd sight.
But consider that a fully grown basking shark can grow up to 36 feet in length, its mouth can open up to 3 feet wide and it weighs between 6,600 and 13,000 pounds — yet it feeds on microscopic prey.
It is the second largest known fish in the sea, and it's a wonder this majestic marine animal ever finds enough plankton to fill itself up.
You can see in the National Geographic video above just how spectacular this shark is, and just how intimidating it would be to see that large mouth if you were swimming nearby.
Basking sharks are truly unique in their appearance and their behavior. Here are several facts about them that may give you even more appreciation for their existence.
1. Basking sharks were once called sunfish
These large sharks were once shrouded in mystery, just like many ocean creatures were back in the 17th and 18th century. As a result, they were named based on certain habits.
In Scotland and Ireland, they were called sunfish because they were often seen near the surface and seemed to be floating up toward the sunlight.
In 1769, a Welsh naturalist named Thomas Pennant decided to change their name to differentiate them from ocean sunfish.
He ultimately landed on basking shark because of the common phrase to "bask in the sun," relating to its original sunfish name.
Later, those studying the sharks would discover they actually stay near the surface because that's the prime location for the plankton on which they depend for food.
2. They are stinky
Basking sharks are smelly creatures. They are covered in a self-produced mucus and slime. It's a defense mechanism that keeps lampreys and other parasitic ocean creatures away.
The slime is corrosive, and has even been shown to burn through nets over time. The chemicals in this mucus produce a rancid smell.
So there's a chance you could smell this ginormous shark before you even see it!
3. They are one of 3 plankton-eating sharks
A basking shark's mouth and how it eats are unique features to start with, but this creature is also a rarity: It's one of only three sharks that eat plankton.
The other two are the whale shark and the megamouth shark. They each have hundreds of small teeth that help filter what comes into their mouths, along with their gills.
The basking shark takes it one step further. It doesn't suck in water as its two counterparts do; it only filters what flows in.
4. They like to hang out with each other
Basking sharks are considered relatively social, considering they tend to travel in groups divided by sex.
They have been known to form schools of up to 100 members at times.
While there's still a lack of information about their mating and reproduction habits, they tend to be visible in early summer as they travel to northern Europe to mate.
Researchers have yet to pin down the exact gestation period for basking sharks, but it's believed to be between a year and 3 years.
Their life expectancy is around 50 years, and they only give birth between every two to four years.
5. They are classified as a 'vulnerable' species
Basking sharks are listed as a "vulnerable" species on the IUCN Red List. They are a fully protected species in the U.S. Gulf Coast, Florida, New Zealand, Malta and the United Kingdom.
Despite those laws, they are still frequently fished because of the value of their fins, liver and oil. Back in the 1700s and 1800s, the oil from their livers was commonly used for lamp fuel.
The population has drastically decreased over the past 20 years, but marine protections are expected to revive those numbers.
Add these beautiful creatures to the list of many that humans must make a true effort to protect in order to maintain their existence on our planet.