The Thresher Shark is also known as the Alopias Vulpinus or Fox Shark. Its name comes from the sharks unusually large tail (caudal fin), which is in most cases, as long as the shark itself!
Today, there are three living species of this Shark:
But experts are still puzzled about the possible existence of a fourth species. This mystery continues to elude enthusiasts, but many believe it’s only a matter of time before this fourth species is confirmed.
It’s origin is also surrounded by mystery. Most likely, the closer relative of the Fox Shark is the Megamouth Shark. Scientific studies are ongoing to try and resolve the many mysteries that surround this unusual and unique fish.
The largest known Thresher Sharks reach a length of more than 6 meters (20ft) and weigh 600 kilograms (216 pounds). Bigeye Threshers are normally the largest with Pelagic Threshers being the smallest.
These are slow growing sharks. They reach their maturity between 8 and 13 years old and live about 22 years. Again, there is quite a bit of mystery here. Some believe this shark is capable of living much longer, but simply hasn’t been verified.
Although Thresher Sharks love open and deep waters, they are also found in shallow waters near coastal areas. They are generally not found deeper than 500 meters.
They favor the Pacific and Indian Oceans, especially at the continental shelves of America and Asia. But the exact habitat, again, remains largely a mystery. There are seen Threshers around Bali and the Gili Islands, Indonesia.
In addition to electro receptors that all sharks have, which gives them they ability to detect electrical impulses from living creatures, they also have an extraordinary heat exchanger system. They’re called “endoderms”, which means that they have special thermoregulation. In other words, they produce heat through an internal body mechanism such as enhancing their metabolism and muscle shivering. This is largely a unique feature in Thresher Sharks.
For the most part, they are rogue mavericks and remain largely independent. But on occasion, they join together in large groups. This phenomenon has mostly been observed in the Indian Ocean. The reasoning for these get togeathers is currently unknown.
These are very athletic sharks. They are known for slaying their prey with their huge tails and are famous for special jumping techniques and behavior called “breaching” where they jump out of the water and into the air.
While hunting, they launch themselves with their whole body out of the water and perform wild turns. They love to hunt schools of fish in the open Ocean waters and prefer Tuna, Mackerels, and sometimes go after certain breads of Seabirds.
As with so many other aspects of this mysterious shark, the reproductive behavior is not well explored. We do know that they are Viviparous, which means that eggs evolve in the uterus until birth.
In general, they give birth to 2 to 5 pups at a time and the pups normally have a length of 120 to 160cm.
There is a special phenomenon called “oophagy” in the womb. The pups actually leave their eggs, still in the womb, and feed themselves with all the unfertilized eggs.
Relationship with Humans
The largest threat to the Thresher Shark is human fishing. Many fisherman catch them for sport, while others catch them for their fins, liver oil, tails, and flesh.
Due to recent population depletion, new laws are being enacted to help protect this species from upsetting the fragile balance of the marine ecosystem, especially since these sharks have a low reproductive rate as compared to other sharks.
This species poses very little threat to humans. The largest threat of injury is divers getting hit with the enormous tail. Attacks of any kind on humans are almost unheard of.