The hammerhead shark, instantly recognizable by its wide, flattened head structure known as the cephalofoil, is one of the ocean’s most unique and compelling predators. This unusual morphology has long fascinated researchers, prompting questions about its function in the shark’s ecology. Hammerheads have evolved highly specific hunting methods that allow them to target certain animals dwelling on the ocean floor.
Confirmation of Stingray Predation
Hammerhead sharks are highly specialized predators of stingrays, with the Great Hammerhead (Sphyrna mokarran) showing a particular preference for them. Rays and skates often constitute a significant portion of the Great Hammerhead’s diet. This specialization is possible because the shark has developed a remarkable tolerance for the stingray’s primary defense mechanism.
The venomous barbs located on the stingray’s tail are frequently found lodged in the mouths and digestive tracts of hammerheads. The presence of these spines suggests that the shark is immune or highly resistant to the stingray’s toxin. This physiological advantage allows the hammerhead to pursue a food source that is largely unavailable to competing shark species.
Specialized Hunting Techniques
The distinctive cephalofoil functions as a highly effective sensory tool, particularly when hunting buried stingrays. Like all sharks, the hammerhead possesses electroreceptors called the Ampullae of Lorenzini, which detect the faint electrical fields generated by muscle movements. The width of the cephalofoil allows these receptors to be spread across a much broader surface area than on other shark species. This wide distribution turns the shark’s head into a highly sensitive, sweeping scanner that efficiently detects a stingray hidden beneath the sand.
Once the electrical signature of a buried ray is located, the shark employs its unique head shape to manipulate the prey. Observers have documented the hammerhead using its broad, flat cephalofoil to deliver a powerful blow to the ray. The shark effectively slams its head down, pinning the stingray to the seafloor, which immobilizes or stuns the ray. This pinning technique prevents the ray from escaping or using its barb to strike. Once the prey is subdued, the hammerhead pivots and takes large, targeted bites, often starting with the ray’s wings.
What Else Hammerheads Eat
While stingrays are a favored meal, the hammerhead shark is an opportunistic predator with a varied diet. They consume a wide array of bony fish, including species like sea bass, grouper, and catfish, which they capture in both coastal and open-ocean environments. Larger hammerhead species, such as the Great Hammerhead, are also known to prey on smaller sharks, including other hammerheads.
The diet of hammerheads also includes invertebrates, such as crustaceans and cephalopods. They actively hunt for crabs, shrimp, squid, and octopus, using their acute senses to locate these creatures in diverse habitats. Dietary composition can vary considerably depending on the specific species of hammerhead and its geographic location. For instance, the smaller Bonnethead shark is known to feed heavily on crustaceans, sometimes even consuming seagrass alongside its prey.