Shark-Repellent Wetsuits?

TECHNOLOGY

An Australian company has designed a wetsuit that could prevent deaths by making surfers and swimmers look less like shark’s prey. (BBC)

Use our resources to learn more about wetsuits and the people who wear them.

Teachers, scroll down for a quick list of key resources in our Teachers’ Toolkit.

Discussion Ideas

• Why do surfers and swimmers in Australia wear wetsuits? Read through our super-short encyclopedic entry for some help.
  • Warmth. The suit traps a thin layer of water between the suit and the wearer’s skin. So, the wearer is always wet—that’s why it’s called a wetsuit. Body heat warms the layer of trapped water and helps keep the wearer warm.
  • Protection. Because wetsuits offer protection against jellyfish stings and rocky reefs, many swimmers choose to wear them in warm water.

 

• Shark Attack Mitigation Systems founder Craig Anderson says sharks are “highly sensitive animals.” What senses does a shark use to sense and attack prey? Read through this great guide for some help.
  • Sharks have the same five senses that we do, but they have evolved differently.
    • sight. Although sharks rely on excellent vision for hunting, their ability to focus is not as acute as ours.
    • smell. Sharks use their noses to sense animals and objects from kilometers away. Great white sharks can detect a drop of blood in an Olympic-sized swimming pool. (Why anyone would swim with a great white in a swimming pool is another question . . .)
    • sound. Unlike our ears, sharks’ ears are completely internal. Many scientists think sharks don’t “hear” in the same way we do, and sound may not play a role in locating prey. Sharks use their ears primarily for balance and equilibrium.
    • taste. Sharks have taste receptors in their mouths (though not on their tongue). These receptors determine whether a meal is accepted or rejected after an exploratory bite. Taste does not play a role in locating prey.
    • touch. Unlike us, sharks have two senses of touch.
      • Physical contact, such as nosing or even biting potential prey, is associated with touch as much as smell or taste.
      • The second sense of touch is experienced through a shark’s lateral line canals. Lateral lines are series of tiny pores that act as sensory organs along the shark’s body. “As water is displaced by the movement of creatures in the sharks surroundings, small waves are created which move away from the disturbances, like ripples on a pond. As these waves pass over the hairs which line the lateral line canals, the hairs are disturbed and send signals to the brain. The shark’s own movement also creates these waves which then bounce off obstructions and return to the shark, creating a kind of vibration echo map of its surroundings. The frequency or erratic nature of the vibrations indicate whether any animals in the area are sick or injured.” In other words: Lateral lines give the shark amazing, long-distance sensory perception.
  • In addition to the five senses we’re familiar with, sharks have a “sixth sense” alluded to in the BBC video: electroreception.
    • electroreception. Sharks have uniquely evolved pores around their snout (called the ampullae of Lorenzini, visible as freckles in the photo above) that allow them to detect electrical signals in their habitats. “[T]he ampullae are so sensitive that they can pick up voltage fluctuations of just 10 millionths of a volt, or the equivalent of the electrical gradient of a AA battery with wires put into the sea 1 mile apart. It has been suggested that the widened heads of the hammerhead family may be an adaptation designed to increase the triangulation capabilities of their electroreception.”

 

• What shark sense do the new wetsuits seek to disrupt?
  • Sight. Sight is the last sense employed by a shark before a bite or attack.

 

• How do the new wetsuits disrupt a shark’s sense of sight?
  • The new suits aim to confuse sharks by taking advantage of their weak visual resolution power, or ability to focus on an object. Both wetsuits break up the silhouette of a single body with bold stripes or patterns. In the wetsuits, “you’re not a contiguous body, you are a few blobs”—or, more to the point, you don’t look like a seal.
    • The black-and-white wetsuit is designed for wear at or near the surface of the ocean, where “no matter what color you’re wearing, you’re always going to be silhouetted against the sun,” appearing in black and white.
    • The aqua-blue wetsuit is based around three colors visible to sharks in slightly deeper water. Each color matches a color at a particular time of day, making that part of the suit virtually invisible to the shark. Like the black-and-white suit, this breaks the swimmer’s silhouette and confuses the shark.

 

TEACHERS’ TOOLKIT

BBC: The wetsuit that repels sharks

Nat Geo: What is a wetsuit?

Elasmodiver: Shark Senses