12 Adaptations of the Great White Shark

12 Adaptations of the Great White Shark

12 Adaptations of the Great White Shark

Great_White_Shark
Great White Shark by Elias Levy cc2.0

The great white shark is one of the most feared creatures in the ocean, but even it has had to adapt to its environment in order to survive. Here are the most notable adaptations of the great white shark.


1. Size

Great white shark size comparison
Size comparison between a great white shark and a human. Author: Kurzon/CC BY-SA 3.0

On average, great white sharks grow 15 to 17 feet long — longer than a pick-up truck. Now, it may be a dwarf compared to its prehistoric cousin, the megalodon, but then again, the megalodon fed on larger prey, including giant whales. The great white shark’s size is enough to make it one of the ocean’s top predators, with its only predators being larger great white sharks and killer whales.




2. Color

Great White Shark Counter Shade
Great White Shark against the sunlight. Image credit: Elias Levy/CC BY 2.0

In spite of its name, the great white shark isn’t entirely white. In fact, only its underside is white, while its top is bluish gray. This coloration is a form of camouflage called countershading. From below, the great white shark is hard to see because its white skin is against the light and in the same way, from above, its darker skin blends in with the water.

3. Shape

Shape of the Great White Shark
Shape of the Great White Shark. Image credit: Elias Levy/CC BY 2.0

What is the shape of a great white shark? The answer: it is shaped like a torpedo. Just as a torpedo cuts through the water, a great white can go up to 35 miles per hour. This speed allows it to charge toward its prey in ambush and also allows it to migrate in search of food, ideal water temperature and mates.

4. Smell

Great_White Shark Sense of Smell
Image credit: lwpkommunikacio/CC BY 2.0

What must every good hunter possess? A good nose, of course. Of all the senses a great white shark possesses, its sense of smell is the most acute, allowing it to smell a single drop of blood 3 miles away. Its smelling organ, called the olfactory bulb, is the largest among all sharks.

5. Vision

Great White Shark's vision
Image credit: lwpkommunikacio/CC BY 2.0

Great white sharks have excellent eyesight, as well. Their retina (the layer of the eye sensitive to light) is divided into two areas, one for daylight and one for dim light. They are especially good at seeing in dim light, as in deep waters, which is why they usually hunt at night. Their eyes have a special layer called the tapetum lucidum, which glows in the dark and reflects light back. Also, a great white shark’s eyes are far apart, giving it almost 360-degree vision. Almost. Its blind spots are right in front of its snout and right behind its head, which is the spot killer whales go for.

Great white sharks don’t have eyelids, so in order to protect its eyes during attacks, it rolls them back into their sockets, preventing them from getting scratched if their prey fights back.

6. Ampullae of Lorenzini

Electroreceptors_in_a_sharks_head
Example of electroreceptors in a sharks head, including Ampullae of Lorenzini and Lateral Line canals. By Chris_huh image

More than their sight or their smell, though, great white sharks rely on their sixth sense to find food. What is this sixth sense? It’s called the ampullae of Lorenzini.

Basically, the ampullae of Lorenzini consists of a network of cells around the great white shark’s head, pores that appear as tiny black dots on the skin, that are connected to sacs filled with a jelly-like substance. These cells are able to detect electrical fields in the water. Every living creature has an electrical field. The larger the creature, the larger the electrical field. The great white shark zones in on this and finds prey. In addition, it uses these special cells to navigate through the open ocean, guided by the Earth’s electromagnetic fields.

7. Rete Mirabile

Rete mirabile
Example of a Rete mirabile/GFDL

Most sharks are cold-blooded. What this means is that they cannot regulate their own temperature — instead, they take on the temperature of their immediate environment. If they are in warm waters, they will feel warm. If they are in cold waters, they will feel cold.

The great white shark, however, is partially warm-blooded. That means it can regulate its own temperature to a certain extent. This is because it has the rete mirabile, a network of veins and arteries that conserve body heat. By mixing the cold blood from the arteries with the warm blood from the veins, the rete mirabile keep certain parts of the shark’s body warmer than the surrounding water.

8. Multiple Gill Slits

Great White Shark's Gill Slits
Image credit: Elias Levy/CC BY 2.0

Most bony fish have just one gill slit on each side of their bodies. Great white sharks, however, have five to seven. This is because they take in a lot of oxygen. In fact, they ram oxygen into their bodies as they move forward, which is why they have to keep moving. If they don’t, they won’t be able to breathe and they will suffocate and die.

9. No Bones

Great white shark's skeleton
Great white shark’s skeleton CC0 Public Domain Image.

As strong as a great white shark appears, it actually has no bones. All it has is cartilage, the same substance that makes up our noses and ears. This substance may not be that hard, but it is pretty tough and more importantly, it is light and flexible, which allows the shark to keep moving. As we already mentioned, great white sharks have to keep moving in order to keep breathing.

10. Teeth

Great_White_Shark_Teeth
Great white shark’s teeth. Image credit: Lukoi, (CC BY 2.0)

What is the downside of having no bones? Well, one is that the great white shark’s teeth easily fall out. Look at your teeth. They are embedded deep into your bone, which is why they stay in place. The teeth of a great white shark, however, aren’t embedded like that, and so they easily come out.

This isn’t a problem, though. In fact, it’s a good thing, since the great white shark doesn’t get hinged on its prey, especially if that prey is giving a nasty fight. It can leave its teeth sunk in the prey and swim away, waiting for it to bleed to death. It’s much like sticking a knife into someone and waiting for that to do the damage.

Also, the great white shark has lots of teeth — as many as 300 at any given time — so even if a few come out, it will still have enough left to finish any meal. As for the ones that are lost, new ones will quickly grow, but not exactly in the same place. What happens is that the teeth move forward to close the gap and the new teeth grow at the empty space in the back.

11. Appetite

Great White Shark's appetite
Image credit: lwpkommunikacio/CC BY 2.0

Great white sharks aren’t picky eaters. They will eat just about everything they can find — marine mammals (like seals, sea lions and sea otters), fish (like tunas, rays and other sharks), sea turtles and seabirds (like gulls and albatrosses). In this way, they can find food wherever they go, and just in case they can’t, they can store fat and oil in their livers, which can sustain them for weeks.




12. Breaching

Breaching Great White Shark
Great White Shark, breaches on the seal. Sled ridden by Jeff Kurr. Image credit: lwpkommunikacio/CC BY 2.0

Great white sharks have been observed practicing a unique behavior called breaching. What this means is that they launch their bodies out of the water so that they are parallel to the surface. This allows them to capture seabirds and seals, and sometimes they even use the same method to jump onto fishing boats! Scary, isn’t it?

Also see:
Why Do Great White Sharks Attack Humans?
Great White Shark Facts!
10 Facts About Great White Sharks


Sources:

http://ocean.si.edu/great-white-shark
http://oceanofk.org/sharks/sharkAnatomy.html
http://en.wikipedia.org/wiki/Great_white_shark
http://animals.nationalgeographic.com/animals/fish/great-white-shark/

Click here to view the complete list of sources…

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