9 Shark Facts That Will Make Your Head Swim
June 19, 2019
Sharks are some of the most fascinating and misunderstood creatures on the planet. Think you know a lot about sharks? Dive in and find out!
1. Sharks Are a Special Type of Fish
Unlike cetaceans (whales, dolphins, and porpoises), pinnipeds (seals, sea lions, and walruses), and sirenians (dugongs and manatees), sharks aren’t mammals; rather, they are a species of fish that have a skeleton made of cartilage and tough skin without scales. And as opposed to mammals, which are warm-blooded, sharks are cold-blooded (but only in blood, not in demeanor!).
2. Sharks Go Through Many, Many Teeth in Their Lifetimes
Sharks lose their teeth all the time; in fact, some species can go through as many as 35,000 teeth over the course of their lives, keeping the shark tooth fairy VERY busy. However, the ability to lose teeth easily is actually key to the shark’s effectiveness as a predator; broken or worn-down teeth are replaced by new, sharper pearly whites.
3. Sharks Have Unique Family Trees
Female sharks sometimes mate with multiple male sharks; this can result in offspring with different fathers, making the pups (the name for baby sharks) half-siblings even though they’re from the same litter. Scandalous!
4. Shark Skin is Not Smooth
In fact, it feels like sandpaper. According to NOAA Fisheries, shark skin is “made up of tiny teeth-like structures called placoid scales, also known as dermal denticles.” These scales point toward the shark’s tail and help reduce friction as the shark swims through the water, enabling it to swim faster.
5. Sharks Have Sneaky Coloring
Sharks are countershaded, which is a method of camouflage in which the top of the animal (known as the dorsal side) is darker and the underside (the ventral side) is lighter. When viewed from above, sharks blend in with the ocean depths beneath them; when seen from below, the shark’s belly blends in with the sky. As a result, predators and prey have a harder time spotting the shark.
6. Sharks Can Be Put into Trances
We don’t recommend doing this (especially to the shark seen below) but if you turn a shark over on its back, it can enter a trance-like state called tonic immobility. Its function isn’t entirely certain, although it’s thought that turning a shark over disorients them and causes them to enter this state. Researchers studying sharks often use this technique to subdue the animal. If undisturbed, sharks can stay in this state for up to 15 minutes—kind of like a nice power nap.
7. Mature Whale Sharks Are As Big As School Buses
Measuring up to 40 feet (12 meters) long and weighing an average of 20.6 tons, whale sharks are the biggest fish in the world. Despite their immense size, whale sharks are filter feeders, opening their jaws and filtering all the tasty plankton and small fish that lie in their path. Whale sharks are docile and pose no threat to humans; in fact, they will often swim alongside people and even let them hitch a ride.
8. Thresher Sharks Have Epic Tails
Thresher sharks, also known as fox sharks, have tails that can be as long as the rest of their bodies and they use these tails as deadly weapons. After accelerating toward their prey, thresher sharks fling the tip of their tail over their body, striking their prey and then casually feeding on the pieces. Thresher sharks are one of only a few animals in the world that hunt with their tail, and the only species of shark known to do this.
9. Sharks Are Indeed Misunderstood
Yes, sharks look scary and do occasionally attack people but shark attacks are still extremely rare; the average American has a 1.625 in a million chance of being attacked by a shark, which means you’re actually more likely to be struck by lightning than attacked by a shark. Humans have a far deadlier impact on sharks. An estimated 100 million sharks are killed every year. This is especially devastating because many sharks sit atop the food chain and help maintain balance in their marine communities.
Written by Whitney Currier for Knockaround.