Today, we’re looking at a deep-sea shark with a remarkable way to catch prey. It is the goblin shark. When it opens its mouth, its jaws can shoot forward.
Transcript
Welcome to Slow English FM. This is Daily Random Facts, where we explore surprising facts and explain how they work in clear English. Today, we’re looking at a deep-sea shark with a remarkable way to catch prey.
EmmaIt is the goblin shark. When it opens its mouth, its jaws can shoot forward. The Australian Museum explains that two ligaments stretch as the jaws close. Opening the mouth releases that tension and drives the jaws forward to catch prey.
The shark also has a long, flattened snout. Pores on its underside connect to a sensory system called the ampullae of Lorenzini. This system lets the shark detect electrical signals from prey. The museum lists fishes, octopuses, squids, shrimps, and crabs as believed food items. But the gut of the museum’s featured shark was empty, so its last meal was unknown.
EmmaScientists have recorded only a small number of these strikes. A 2016 study examined five strike and prey-capture events from two goblin sharks, recorded at sea in 2008 and 2011. The researchers say the shark is rarely observed because its deep-water home is hard to reach and people encounter it infrequently.
In one recorded strike, the jaws reached their farthest point 279 milliseconds after the sequence began. That is less than a third of a second. From the resting position, the upper jaw moved a distance equal to 8.6 percent of the shark’s total length. The lower jaw moved 9.4 percent. Its reported top speed was 3.14 metres per second.
EmmaThe researchers call this ram feeding. The shark opens its mouth fully before projecting its jaws, and its gill openings stay open during the bite. The researchers compare its slender body, small soft fins, and weak, ribbon-like tail with the stronger swimming form typical of mackerel sharks.
The study proposes that this far-reaching strike may help the goblin shark catch prey despite limited ability to swim fast for a long time. Its curved teeth may also help stop prey from escaping once caught.
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Vocabulary in this episode
- deep-sea
Today, we’re looking at a deep-sea shark with a remarkable way to catch prey.
Living far below the surface of the sea.
- prey
Today, we’re looking at a deep-sea shark with a remarkable way to catch prey.
An animal hunted and eaten by another animal.
- prey
Opening the mouth releases that tension and drives the jaws forward to catch prey.
An animal the shark hunts and eats.
- prey
This system lets the shark detect electrical signals from prey.
Animals that the shark may hunt and eat.
- prey
A 2016 study examined five strike and prey-capture events from two goblin sharks, recorded at sea in 2008 and 2011.
Animals caught to be eaten.
- prey
The study proposes that this far-reaching strike may help the goblin shark catch prey despite limited ability to swim fast for a long time.
Animals the shark hunts and eats.
- prey
Its curved teeth may also help stop prey from escaping once caught.
Animals the shark has caught for food.
- tension
Opening the mouth releases that tension and drives the jaws forward to catch prey.
The pulling force stored in the stretched ligaments.
- snout
The shark also has a long, flattened snout.
The long front part of an animal’s head, including its nose and mouth.
- ampullae of Lorenzini
Pores on its underside connect to a sensory system called the ampullae of Lorenzini.
Special organs that help sharks sense weak electrical signals in water.
- strike
A 2016 study examined five strike and prey-capture events from two goblin sharks, recorded at sea in 2008 and 2011.
A quick attack by the shark.
- strike
In one recorded strike, the jaws reached their farthest point 279 milliseconds after the sequence began.
One quick attack in which the shark thrusts its jaws forward.
- strike
The study proposes that this far-reaching strike may help the goblin shark catch prey despite limited ability to swim fast for a long time.
A quick attack in which the shark thrusts its jaws forward.
- at sea
A 2016 study examined five strike and prey-capture events from two goblin sharks, recorded at sea in 2008 and 2011.
In the ocean, away from land.
- infrequently
The researchers say the shark is rarely observed because its deep-water home is hard to reach and people encounter it infrequently.
Not often.
- resting position
From the resting position, the upper jaw moved a distance equal to 8.6 percent of the shark’s total length.
The jaw’s normal position when it is not thrust forward.
- ram feeding
The researchers call this ram feeding.
A way of feeding in which an animal moves forward and takes food into its open mouth.
- far-reaching
The study proposes that this far-reaching strike may help the goblin shark catch prey despite limited ability to swim fast for a long time.
Able to extend a long way forward.