Shark attacks on humans are rare, but they do occur. Understanding what might attract a shark to a person can help people avoid dangerous encounters when swimming or doing other activities in the ocean. There are several factors that can draw a shark’s attention and provoke an attack.
Blood
One of the biggest attractants for sharks is blood. Sharks have an extremely acute sense of smell and can detect tiny amounts of blood in the water from up to a quarter mile away. Their olfactory senses are so strong that some species can smell one drop of blood in an Olympic size swimming pool.
If a human has an open wound or is menstruating while in the ocean, the blood in the water acts like a magnet for sharks. They are drawn to the scent because they associate it with the potential for feeding. This is why people are advised to stay out of the ocean if they have any kind of bleeding.
Erratic Movement
Sharks are very sensitive to vibrations and abrupt motions in the water. Fast or irregular movements that contrast with the ocean’s currents can attract their attention. For sharks, something darting around quickly or splashing on the surface may resemble injured prey or potential food sources.
If people are swimming or surfing in a choppy, erratic manner, it can provoke curiosity or predatory instincts in some shark species. Smooth, steady movements are less likely to garner the same kind of interest from sharks.
Shiny Objects
Sharks have extremely sharp vision. Their eyes are specially adapted to detect contrast, movement, and even the smallest details in their environment. One thing that draws their visual attention is shiny objects or reflective surfaces.
Items like jewelry, dive knives, watches, wetsuits with metallic detailing, or surfboards can reflect light in a way that gets noticed by sharks. If a human is wearing or using gear with flashy, attention-grabbing surfaces, it may attract the interest of a shark or give the impression of fish scales reflecting light.
Fishing Activity
Areas with fishing activity, like piers or spearfishing competitions, can create an unsafe scenario that essentially rings the dinner bell for sharks. The fish blood, bait, and injured fish associated with fishing provide tempting feeding opportunities.
This not only draws in curious sharks to investigate, but also triggers a competitive feeding response. Multiple sharks may converge in the area, increasing the risks. Any humans in the water become at risk for mistaken identity or sample bites.
Habitat
Certain conditions bring sharks closer to shore and into contact with humans more frequently. During their migrations or seasonal movements, some species come near the coastlines and gather around oceanfronts.
Areas with nearby deep drop-offs, estuaries, or seafloor topography that aggregates prey also provide ideal hunting grounds, putting sharks and humans in closer proximity. Understanding shark habitats and movement patterns can identify higher-risk locations.
| Shark Species | Habitat |
|---|---|
| Bull Shark | Swim in shallow coastal waters, often around beaches and in estuaries |
| Tiger Shark | Swim in shoreline regions between reefs and channels |
| Great White Shark | Swim along coasts with nearby seal colonies or rocky outcroppings |
Confusing Identity
One theory for why sharks attack humans is mistaken identity. From below, people on surfboards may silhouetted in a way that resembles their natural prey, like seals or sea turtles. Splashing behaviors also mimic the movements of prey animals.
Even on swim, sharks searching for fish may zero in on the movements or outline of a person if conditions obscure their vision. Wearing flippers and wetsuits creates an even stronger resemblance. The curious shark may take an investigative sample bite, causing serious injury.
Unusual Weather
Certain weather conditions have been associated with increased shark attacks. Tropical storms or cold front weather patterns that quickly change water temperatures, currents, and visibility can displace sharks from their typical territories.
Flooding and runoff events can also wash debris, pollutants, or waste into coastal waters. This contaminates their habitat, forcing sharks to seek cleaner waters where humans coincide. Cloudy low-visibility water may also impede sharks from identifying humans properly.
Protection of Territory
Some shark attacks are defensive acts. Sharks have a strong drive to protect their domain or assert dominance. If a human unintentionally encroaches on a shark’s space, makes direct eye contact, or provokes the animal, it may elicit an attack response.
Situations like swimming near a shark’s feeding ground or blocking its path can be seen as challenges, triggering defensive behavior. Even shark researchers must exercise caution when documenting their behavior to avoid defensive strikes.
Curiosity
Sharks are highly investigative creatures by nature. Much like human behaviors, curiosity can also account for why sharks approach or bite humans. Younger, less experienced sharks may sample nibble on unfamiliar objects and beings as a means of exploring their environment.
Humans on surfboards, boats, or underwater gear create novel shapes, vibrations, and sounds that fascinate sharks. Even without predatory motivations, their inquisitive nature makes them prone to checking out interesting commotions and unfamiliar forms in their domain. An exploratory nibble can still cause injury.
Rogue Behavior
Very rarely, individual sharks exhibit strange behavior that deviates from norms. Cases have been documented of particular sharks relentlessly circling or even ramming boats. Some have waited outside popular beaches to target humans.
It’s speculated that these could be injured, starved, diseased, or territorial sharks. Their odd aggression toward humans suggests rogue behavior outside of normal predatory motivations. Further research aims to determine what prompts this dangerous conduct in a small number of sharks.
Decreased Fear of Humans
Decades ago, sharks tended to avoid areas of human activity, which offered a degree of natural separation. But some researchers propose that years of exposure to humans have caused certain species to associate human presence with food.
Constantinteractions through activities like chumming or cage diving may erode a natural wariness of people in the water. Boat accidents and fishery discards provide easy meal opportunities. Over time, conditioning may embolden some shark species rather than discouraging them.
Conclusion
Shark attacks on humans are complex interactions that stem from a variety of causes. Curiosity, territorial behavior, mistaken identity, and opportunity for feeding can all motivate sharks to approach and bite humans. People can reduce their risk by being alert to shark habitats, avoiding areas with fishing activity, watching their movements, and not swimming with open wounds.
With responsible practices, we can safely enjoy ocean activities and appreciate sharks in their natural habitats, while minimizing the potential for dangerous interactions on both sides. Ultimately, a better understanding of shark behavior leads to greater safety and lower risks when our worlds inevitably overlap.