What is a Brazilian luminous shark? How does she look? What eats such a predatory cartilaginous fish and how does it breed? The answers to these and other questions can be found in our material.
Brazilian Luminous Shark: Description
Representatives of the species have a cigar-shaped elongated body. The animal's face is dull. Large eyes are widely set on it, which help the fish navigate in the oceanic depths. The nostrils are covered with small skin folds. The Brazilian luminous shark has a miniature mouth with thick lips adapted to be sucked to the victim.
On the back there are two small fins, shifted closer to the tail of the body. The pectoral trapezoid fins also have small dimensions, and the caudal fins are quite large. The edges of the fins contain a black edging.
The body of the Brazilian luminous shark is covered with flat square scales. Their edges are slightly raised, and the central part is concave inward. The scales have a dark brown tint.
Habitat
What latitudes does the Brazilian luminous shark live in? The distribution of this fish is limited to tropical island regions. You can meet representatives of the species south of Japan, in the coastal areas nearby Australia, New Zealand, Tasmania. Brazilian luminous sharks inhabit the waters that wash South America, near the Cook Islands and in Fiji.
Typically, these animals stay close to the islands. In the daytime, such fish prefer to stay at considerable depths. With the onset of darkness rise closer to the surface. The range of vertical migrations is more than 3500 meters.
Dimensions
The size of the Brazilian luminous shark is frankly small. The body length of such cartilaginous fish can reach a maximum of 50 centimeters. It is noteworthy that males are much smaller than females. Their length averages 25-35 cm.
Nutrition
How does the Brazilian luminous shark feed? Having found the victim, representatives of the species dig into the flesh. Such hunters literally cut out a piece of meat, rotating around its own axis and wielding teeth arranged in a circle. Then the Brazilian luminous shark swims away from prey, absorbs the torn part of the carcass and hides in safe depths. A characteristic rounded mark of about 7-10 cm in diameter remains on the victim’s body.
Most often, large marine animals, in particular, pinnipeds and cetaceans, suffer from luminous sharks. These predators also hunt deep-sea slopes. Often, other sharks become victims of such cartilaginous fish. Small squids, the sizes of which do not exceed 30 cm, are their prey.
The rounded scars left by the Brazilian luminous shark can be seen on the bodies of a wide variety of marine mammals in tropical regions. The victims of such predators remain alive. An exception is when luminous sharks attack prey by numerous groups. In such situations, affected creatures die as a result of exhaustion or loss of blood.
Luminescence ability
On the body of the Brazilian luminous shark, the photo of which can be seen in our article, there are specific luminescent cells. The latter are called photophores. They act as a source of a sufficiently strong greenish glow. The effect can persist for several hours after removing the shark from the water. Such light makes the predator less visible from below, which acts as an effective way of camouflage.
The pattern that the luminescent cells form resembles a small fish to large marine animals. Such a decoy becomes most effective if luminous sharks seek food in groups. They attract a potential victim who believes they have found a large school of fish. Then, miniature predators attach themselves to their prey, whether it be a cetacean, a dolphin, a pinniped or a shark of another, larger species. Cutting out a large piece of flesh from the victim's body, the luminous sharks are removed to a depth.
Breeding
Little is known about how the breeding of the Brazilian luminous shark occurs. Like other predatory cartilaginous fish, they are viviparous. The embryo develops from a kind of eggs, absorbing a nutritious yolk. In one litter, there may be more than a dozen embryos.
The female produces offspring after a long pregnancy. Researchers believe that the bearing of the fetus in luminous sharks can take about 2 years. After birth, the cubs do not need custody from the mother. Having been born, they immediately swim away into the depths of the ocean and begin an independent search for food.
Is a luminous shark dangerous to humans?
Representatives of the species prefer to stay most of the day at considerable depths. Therefore, their meeting with a person is extremely rare and is often an accident. At the same time, several cases of the attack of luminous sharks on humans are known. So, in 2009, off the coast of Hawaii, an attack was made on a man named Mike Spaldin. The latter decided to overcome a small strait by swimming. After meeting with a luminous shark, characteristic marks of a rounded shape remained on his body.
There are reports according to which from the depths of the sea repeatedly raised the bodies of drowned, covered with wounds from the bites of such predators. Presumably, the damage was done posthumously.
In 2012, a group of Brazilian luminous sharks attacked a catamaran of Russian navigator Anatoly Kulik in the middle of the Pacific Ocean. Predators managed to make a gaping hole in one of the tanks that kept the ship afloat. According to other travelers, such attacks repeatedly occurred during the crossing of the Atlantic.
It is worth noting that all the above cases of aggression of the Brazilian luminous sharks in relation to humans are isolated. In general, the presented species is safe for people.
Interesting Facts
It is interesting to know the following about these predators:
- Brazilian luminous sharks often attack submarines. In the 70s of the last century, a case was recorded when the American military submarine was forced to return to the base for the restoration of sonar domes. The reason was their damage as a result of the attack of luminous sharks. After finding out the cause of the malfunction, fiberglass protective covers were installed on the sonars. Often, the bites of such predators suffer from underwater telecommunication cables and oceanographic equipment.
- In Britain, this deep-sea animal is known as the cookie cutter. Literally, the concept is translated as a cookie cutter. Luminous sharks leave wounds on the body of victims with precisely such outlines. In addition, such predators are called cigar sharks because of the specific shape of the body.
- The Brazilian luminous shark leads a solitary life. The only exception is the period of mating activity. With the onset of the mating season, representatives of the species gather in fairly large groups.
- Like other sharks, these predatory fish periodically lose their teeth. However, representatives of the species do not part with them, but prefer to swallow. Scientists believe that this behavior is explained by the need of the animal to replenish calcium reserves.
- Luminous shark is fed exclusively at night. This allows predators to attract potential victims using luminescence on the body.
- Due to their fragmentation and small size, luminous sharks are not of particular interest to fishermen. They are rarely found in planktonic networks and bottom trawls.
- The approximate number of luminous sharks in the world's oceans is still unknown. Due to the widespread distribution of the species and the lack of commercial value, such predators do not need protection from international environmental organizations.