Hammerhead Sharks | JONATHAN BIRD'S BLUE WORLD

Of all the animals in the oceans, the hammerhead shark may be one of the strangest looking. The exact purpose of the wide, flat head is a mystery, but several theories abound. We travel to the shark-infested waters of the Galapagos in Ecuador and to a research station in Hawaii to learn about the unusual habits of these sinister-looking sharks. Jonathan swims in schools of hundreds of hammerheads, and yet the sharks ignore him. What are the sharks up to?

#underwater #scuba #scubadiving #sharks #hammerheadsharks #hawaii #galapagos #ecuadaor #scallopedhammerheads

**********************************************************************
If you like Jonathan Bird's Blue World, don't forget to subscribe!

You can buy some Blue World T-shirts & Swag!
http://www.blueworldtv.com/shop

You can join us on Facebook!
https://www.facebook.com/BlueWorldTV

Twitter
https://twitter.com/BlueWorld_TV

Instagram
@blueworldtv

Web:
http://www.blueworldTV.com
**********************************************************************
In the Galapagos Islands, during certain times of the year, large aggregations of Scalloped Hammerheads come together to circle around Darwin Island. Scalloped Hammerheads normally live in the open ocean, but here at Darwin Island they come close to shore in large numbers.

Considering the vast numbers of fish here, it would be logical to assume that the sharks come to feed. Yet, nobody has ever witnessed the sharks feeding.
The Galapagos Islands are a remote archipelago 600 miles off the coast of Ecuador in the Pacific Ocean.

Hammerheads are most common at the northernmost island of Darwin, famous for its stone arch.

Hammerheads are of course known for their strange, flattened heads. But you have to wonder…what is that flat head for?

Shark biologists put their own heads together to figure it out. At first, they speculated that it gave the hammerhead wider stereoscopic vision. But that didn’t work: hammerhead eyes face in opposite directions, meaning they can’t see in stereo. The wide head probably has nothing to do with eyesight.

So maybe it has to do with the sense of smell. Wider spaced olfactory organs would help the hungry shark sniff out prey more accurately.

Well, not really.

Although the nostrils and olfactory organs are widely spaced, a groove along the front of the head effectively connects them together. Therefore, they don't give the hammerhead a better sense of directional smell than any other shark.

Scientists finally hit upon a graceful reason for the awkward head: It helps the hammerhead turn faster by eliminating the need for large pectoral fins.

Some sharks, like white tip reef sharks can rest all day if they want, just gulping water to ventilate their gills, the shark equivalent of breathing.

Hammerheads, on the other hand, cannot accomplish this. Like most pelagic sharks, they must keep swimming not only to stay up off the bottom, but to breathe. In an ironic twist of fate, if a hammerhead stops swimming, it will drown. The big flat head is a wing to keep the hammerhead up off the bottom.

Researcher Kanesa Duncan at the University of Hawaii is studying Scalloped hammerheads. She catches the sharks when they are just pups, only a few weeks old, in Kaneohe Bay on Oahu.

By holding the shark upside down, she places it in a kind of trans called Tonic Immobility.
She frequently puts the pup back in the water to aerate the gills.

Once aboard the boat, she first measures the shark while an assistant records the data. Next she implants a small visual tag with a number on it through the shark’s dorsal fin. This does not hurt the shark at all. The fin is almost completely made of cartilage. Next, she weighs the pup.

Back at the lab, Duncan has several captive hammerhead pups that she is working with to determine growth patterns. She wants to learn, among other things, how fast baby Hammerheads grow.

But I still want to know what they are all doing at Darwin Island in the Galapagos, and I finally get a clue when I see a shark being investigated by a fish.

The strong current at Darwin Island allows a hammerhead to swim in place, like a runner on a treadmill, yet hold a fixed position over the reef.

King Angelfish make their homes on this reef and they serve as cleaner fish for the sharks.
Because the sharks get cuts and scrapes, not to mention parasites, that need cleaning, they come to a cleaning station where a King Angelfish is waiting to clean the wounds and eat the parasites.

A shark looking to be cleaned often swims at an angle, with its white belly showing. This body language tells the angelfish to come on over.

Angelfish looking to clean a shark swim up and down in the water to attract the shark’s attention.
Often, something seems amiss to the shark and it rebuffs the fish. The sharks feel vulnerable while they are being cleaned, so they pick a cleaning station carefully. If anything doesn’t seem right, they move on.

Видео Hammerhead Sharks | JONATHAN BIRD'S BLUE WORLD канала BlueWorldTV