The term “brown shark” is a general description, not a scientific classification, often leading to confusion about specific species and their potential danger. This article clarifies the identity of sharks commonly called “brown sharks,” their typical behaviors, and how to interact with them safely.
Defining “Brown Sharks”
The term “brown shark” typically refers to several species with brownish coloration. The Sandbar Shark (Carcharhinus plumbeus) is a prominent example, often called a brown shark. They can reach 8 feet and weigh over 200 pounds, possessing a distinctive tall, triangular dorsal fin. Sandbar sharks are commonly found in shallow coastal areas, estuaries, and sandy flats worldwide.
Another species often mistaken for a “brown shark” is the Nurse Shark (Ginglymostoma cirratum), a slow-moving, bottom-dwelling shark with a yellowish-tan to dark brown hue. Adults average 7.5 to 8 feet long and have a broad head with small mouths. Juvenile Lemon Sharks (Negaprion brevirostris) can also appear yellowish-brown or olive-grey. These sharks typically inhabit shallow coastal waters, including mangroves and coral reefs, and can grow to 7-10 feet.
While often grey, juvenile Bull Sharks (Carcharhinus leucas) can sometimes have a brownish appearance. These robust, powerful sharks are known for their ability to tolerate both saltwater and freshwater environments. They are found in coastal waters globally and can grow to significant sizes, with females exceeding 11 feet.
Understanding Their Behavior
Most shark species commonly called “brown sharks” are not aggressive towards humans and tend to avoid interaction. Sandbar sharks, for instance, are docile, with attacks on humans being very rare. They are opportunistic bottom-feeders that primarily hunt small fish, mollusks, and crustaceans, often at night. Interactions are typically curious rather than predatory.
Nurse sharks are typically docile, often resting motionlessly on the seafloor during the day. While capable of a powerful bite, incidents usually occur when they are provoked or disturbed. Their diet consists mainly of bottom-dwelling creatures like crabs, lobsters, and small fish, captured using a strong suction feeding mechanism.
Lemon sharks do not pose a significant threat to humans, with unprovoked attacks being rare. They primarily feed on fish, crustaceans, and rays, and are often more curious than aggressive towards divers. Bites, when they occur, are typically due to mistaken identity or provocation, not predatory intent.
Bull sharks, despite their reputation, do not view humans as prey. Attacks, though more frequent than with other “brown” species due to shared habitats, are rare. They are often attributed to their territorial nature or curiosity, especially in murky waters. Their diet is varied, including fish, other sharks, and marine mammals.
Encountering Brown Sharks Safely
To minimize the risk of encounters with any shark, including “brown sharks,” consider these safety measures:
Swim or surf at beaches monitored by lifeguards.
Always swim in groups rather than alone.
Stay close to shore.
Avoid entering the water at dawn, dusk, or night.
Do not swim with open wounds or if bleeding.
Avoid murky water, river mouths, and areas near active fishing or spearfishing.
Refrain from wearing shiny jewelry or high-contrast swimwear.
If a shark is sighted, leave the water quickly and calmly, alerting others.
Never provoke, feed, or harass any shark.