While both manatees and various shark species inhabit coastal waters, documented instances of sharks preying on manatees are exceedingly rare. This rarity stems from a combination of factors: the manatee’s characteristics, their preferred habitats, and the typical predatory behaviors of sharks.
Manatee Characteristics and Preferred Habitats
Manatees are large, herbivorous marine mammals, typically 9 to 10 feet long and weighing around 1,000 pounds, though some exceed 13 feet and 3,500 pounds. They possess a robust body and thick, leathery skin, offering some protection. Manatees spend much of their time grazing on aquatic vegetation in shallow, warm waters.
Manatees prefer habitats such as slow-moving rivers, estuaries, canals, and coastal areas where seagrass beds and freshwater vegetation are abundant. They are tolerant of varying salinity levels, moving freely between freshwater and marine environments, but they cannot tolerate temperatures below 68 degrees Fahrenheit for extended periods. Their preferred depths are typically 1 to 2 meters, and they generally avoid waters deeper than 6 meters. This combination of large size and preference for shallow, often turbid waters makes them less accessible or appealing as prey for many shark species.
Shark Predatory Behavior
Sharks are apex predators whose hunting strategies target specific prey. They generally select prey offering a high caloric return for the energy expended, often focusing on fish, seals, or sea lions. Sharks utilize various sensory inputs, including smell, electrical signals, and movement, to locate food.
Attacking a large, robust animal like a manatee can be energetically demanding and potentially dangerous for a shark, as much of the carcass might go to waste. Many large predatory sharks typically inhabit deeper ocean waters, which contrasts with the shallow, often brackish or freshwater environments favored by manatees. While sharks are opportunistic feeders, manatees generally do not fit the profile of their preferred, energy-efficient food sources.
Documented Interactions
Documented cases of sharks attacking manatees are very few. The International Shark Attack File, which tracks shark-human interactions, has recorded very few confirmed shark attacks in areas where manatees live, with no reported attacks specifically on manatees. When these rare incidents do occur, they are often attributed to mistaken identity, curiosity, or involve manatees that are already injured, sick, or very young. Manatee calves, being smaller, are more vulnerable to potential predation.
Bull sharks are one of the few species noted for potential interaction, as they can tolerate both fresh and saltwater and may venture into the shallow, estuarine habitats favored by manatees. While some manatees bear scars that could be from shark bites, definitive evidence linking these injuries to direct predatory attempts is limited, often suggesting exploratory bites rather than full hunting endeavors. The primary threats to manatees are overwhelmingly human-related, including collisions with watercraft and habitat loss, rather than shark predation. Over 96% of adult Florida manatees, for instance, bear scars from boat strikes.