hawaiian monk seals mainly prey on reef-dwelling bony fish, but they also prey on cephalopods and crustaceans. juveniles and subadults prey more on smaller octopus species, such as "octopus leteus" and "o. hawaiiensis" (nocturnal octopus species), and eels than do adult hawaiian monk seals. adult seals feed mostly on larger octopus species such as "o. cyanea". hawaiian monk seals have a broad and diverse diet due to foraging plasticity, which allows them to be opportunistic predators that feed on a wide variety of available prey. tiger sharks, great white sharks, and galapagos sharks are both predators of the hawaiian monk seal.