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The electric “radar”

Raya marina

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Stingrays can be considered a branch of the shark family that has adapted its life to the ocean floor. In the long journey of evolution, they flattened their bodies, making them more suitable for searching for food in sandy bottoms.

However, their long and stationary presence on the seabed made them highly vulnerable to predator attacks. To protect themselves, some species of stingrays developed a venomous stinger attached to the base of their tail. If attacked or sensing a threat, they can wield their sharp tail like a whip in all directions, accurately impaling their assailant with the razor-sharp stinger. The obvious question was how stingrays achieve such precision when their eyes are located at the front of their face, their olfactory nasal openings are on the underside of their body with powerful sense of smell, and they mostly inhabit sandy or muddy bottoms with poor visibility.

Not long ago, it was discovered that stingrays carry a low-power electrogenic organ at the base of their tail, capable of generating a small but rapid electric discharge, approximately four volts. It is believed that the stingray uses this small discharge as a type of sonar. Once the discharge is produced, the animal detects, through specialized receptors, not the echo rebound but rather the deformation of the electric field caused by the attacker’s body. In this way, it can rapidly direct the tip of the stinger towards the threat within fractions of a second.

While the venom injected through the stinger is potent, it would rarely be lethal to a person if applied to the arms or legs. However, it would likely be fatal if applied to the abdomen or chest. Generally, when the stingray stings, it loses its venomous glands in the attack. That’s why some people who have been wounded by a stingray’s stinger were not injected with venom.

Humans have known about stingrays for ancient times. Japanese samurai used the stingers to make arrowheads, and the rough skin of the animal was used to cover sword handles to prevent them from slipping. Aristotle described stingrays as dangerous creatures, and the ancient Greeks discovered that the venom remained in the stinger long after the animal’s death. The stinger was believed to be capable of withering and killing plants if its bark was rubbed with it. Crushed stingers were also used to obtain a dental anesthetic. It was also believed that if a live stingray’s stinger was extracted and immediately attached to the navel of a pregnant woman, it would facilitate childbirth.

The real risk lies in walking barefoot in shallow sandy bottoms where there is a possibility of stepping on a stingray. The stinger is a simple defense mechanism to avoid unpleasant surprises, a reaction to an attack. However, stingrays are incapable of using this system to aggress against humans. On the contrary, they are curious when a diver appears. They are marvelous hosts of the underwater world, teaching us to fly like a bird, but beneath the water.

“You cannot defend what you do not love, and you cannot love what you do not know.”