Tiger sharks are large apex predators found in tropical and subtropical waters worldwide. Their size and reputation often evoke fear, but understanding their natural behaviors and human encounters provides a clearer perspective on their interactions with people.
Understanding Tiger Shark Behavior
Tiger sharks are known for their opportunistic feeding habits, earning them the nickname “garbage cans of the sea.” Their remarkably diverse diet ranges from fish and crustaceans to sea turtles, birds, marine mammals, and other sharks. Inedible items like license plates and tires have even been found in their stomachs. Their diet changes as they mature; smaller tiger sharks primarily consume fish and mollusks, while larger individuals expand their diet to include bigger prey such as turtles, birds, and marine mammals.
These sharks are generally solitary and nomadic, moving extensively between deep offshore waters and shallower coastal areas, including lagoons and harbors. While some sources indicate they are mostly nocturnal, they can be active both day and night, adapting their foraging strategies to available prey. Recent research suggests they might be more social than previously believed, forming larger groups, though this can be influenced by baiting activities.
Factors Influencing Human Encounters
Interactions between tiger sharks and humans often occur due to overlapping habitats, as these sharks frequent coastal waters, lagoons, and harbors where human activity is common. Natural prey in these areas can attract sharks, increasing encounter likelihood. Human activities, such as fishing or chumming, can also draw sharks closer to recreational areas. Chumming, the practice of using bait to attract fish, can alter a shark’s natural behavior and make them more curious or bold.
A common theory for human-shark interactions is mistaken identity, where a shark may confuse a human for its typical prey. This is particularly relevant for surfers, whose silhouette on a surfboard can resemble seals or other marine animals from below. Poor water visibility, such as murky conditions or during dawn and dusk, can contribute to these misidentifications. Splashing or erratic movements can mimic distressed prey, potentially drawing a shark’s attention. Tiger sharks are also naturally curious, and their investigative nature can lead them to approach unfamiliar objects, including humans.
Analyzing Incident Data
Despite common perception, shark incidents involving humans are statistically uncommon. Tiger sharks are responsible for the second-highest number of documented incidents globally, after great white sharks. Records since 1580 attribute 142 unprovoked incidents and 39 fatalities to tiger sharks.
The International Shark Attack File (ISAF) differentiates between “unprovoked” and “provoked” incidents. Unprovoked incidents occur when a shark bites a human in its natural habitat without human initiation. Provoked incidents involve human actions leading to the interaction, such as harassing a shark, spearfishing, or attempting to remove a shark from a net or hook. Many unprovoked incidents are believed to be exploratory bites or mistaken identity, not intentional predation. While great white sharks account for more total incidents, the fatality rate for tiger shark bites can be higher, partly because they are less likely to release after an initial bite. Studies show the survivability of an unprovoked tiger shark bite is around 53%.
Reducing Risk of Interaction
To minimize tiger shark encounters, several precautions can be taken. Avoid swimming in murky water, as reduced visibility increases misidentification. While some shark species are more active at dawn, dusk, or night, tiger sharks are known to bite at any time of day.
To further reduce risk:
Swim in groups rather than alone, as sharks are less likely to approach multiple individuals.
Avoid areas where sharks are known to be present, or where there are signs of baitfish or active fishing.
Avoid wearing shiny jewelry, as its glint can resemble fish scales and attract a shark’s curiosity.
Refrain from excessive splashing or erratic movements, which can mimic distressed prey.
If a tiger shark is sighted, maintain eye contact and slowly retreat towards shore without rapid movements, as swimming away quickly can trigger a predatory response.