Top 10 overraskende ting, du (sikkert) ikke vidste om hajer

Sharks have long been feared as the ocean’s fiercest predators, but there’s much more to these ancient creatures than meets the eye. Having existed for over 400 million years, sharks boast an array of fascinating traits that many people have never heard of. Here’s a countdown of the top 10 most surprising facts about sharks — from their extraordinary senses to their unexpected behaviors.

Some Sharks Can Live in Freshwater

Most people associate sharks with salty seas, but species like the bull shark can thrive in both saltwater and freshwater. Bull sharks have been found far upriver in the Amazon and Mississippi thanks to their ability to regulate the salt levels in their bodies.

They Have an Extra Sense Organ

In addition to the five basic senses, sharks possess a unique organ called the ampullae of Lorenzini. These tiny, jelly-filled pores allow them to detect the electrical impulses of prey — even heartbeats — and navigate using Earth’s magnetic field. This makes them exceptionally accurate hunters.

Some Sharks Can Enter a Dormant-Like State

Species like the Greenland shark move incredibly slowly and have such a low metabolism that their state is almost like hibernation. This allows them to survive in freezing, dark waters and live for hundreds of years.

Sharks Have No Bones

Unlike most animals, sharks don’t have bones. Instead, their skeletons are made of cartilage — the same flexible material found in human noses and ears. This gives them lightweight bodies that move swiftly and silently through water.

Their Skin Cleans Itself

Shark skin is covered in tiny, tooth-like scales called dermal denticles. These reduce drag in the water and help prevent parasites and algae from attaching. It’s nature’s built-in antibacterial armor.

Sharks Have Excellent Night Vision

Sharks’ eyes are highly adapted to low-light conditions. They have a layer called the tapetum lucidum that reflects light back through the retina, improving their vision in darkness — the same reason cat eyes seem to glow at night.

Some Sharks Glow in the Dark

Certain deep-sea sharks are bioluminescent, meaning they can emit light from their skin. This helps them camouflage from predators and communicate in the dark. The glow comes from special light-producing cells.

Some Sharks Reproduce Without Males

In rare cases, species like zebra sharks and hammerheads can reproduce via parthenogenesis — a form of virgin birth where the female produces offspring without male fertilization. It’s an extraordinary evolutionary backup system.

There Are Over 500 Known Shark Species

While most people picture the great white or hammerhead, there are over 500 known species of sharks — from the tiny dwarf lanternshark at 17 cm to the whale shark, which can grow over 12 meters long. Many feed on plankton and look nothing like the stereotypical shark.

Some Sharks Live for Up to 500 Years

Topping the list is the Greenland shark, which may live for as long as 500 years, making it the longest-living vertebrate on the planet. These ancient sharks grow incredibly slowly and don’t reach maturity until around age 150 — true elders of the deep.

Our team may have used AI to assist in the creation of this content, which has been reviewed by our editors.