Sea otters are the main predator of sea urchins and keep the urchin population in check. Eagles may also grab young otters if given the opportunity. Now uncontrolled by sea otters, their natural predator — the urchin population — boomed both in body size and density. Sea otters must also be able to defend themselves from the cold waters in which they swim. On land, young sea otters may face attack from bears and coyotes. As top predators, sea otters are critical to maintaining the balance of nearshore ecosystems, such as kelp forests, embayments and estuaries. The younger sea otters can also be attacked on the water surface by bald eagles. Loss of sea otters therefore can have a huge impact on our coastal ecosystems. sharks and humans are the river otters predators An otter's predators are sharks, humans and bald eagles. The complexity of trophic cascades can vary extensively from place to place, but this basic pattern is the foundation for understanding how sea otters fit into a healthy coastal environment. In the wake of this event, herbivorous sea … In the early 20th century, otters were hunted to near extinction. However, the animals prove a low threat, unlike humans. The government passed a law restricting otter hunting. Sea otters eat sea urchins in abundance where they both occur but also prey on crabs and other crustaceans and mollusks. Young predators may kill an otter and not eat it. Due to the large size of the sea otters, there are few natural predator enemies. Those sea otters that live farther south, mostly hunt for a great white shark, and representatives of those sea otters that inhabit the more northern areas of the Pacific, hunt for killer whales. Then in 1914 a remnant population of about 50 southern sea otters was found along the rugged Big Sur shoreline. As others have written, killer whales and sharks are the biggest threat to sea otters of all sizes if they are in the ocean. Sea urchins greedily graze on kelp when otters are not around, but in the presence of the predators, urchins hide in crevices and eat just the plant scraps. Common predators of sea otters include various predatory marine mammals such as orcas and sea lions. The southern sea otter was widely believed to be extinct due to the expansive fur trade of the 18th and 19th centuries, which reduced the global population from between 150,000 and 300,000 to roughly 2,000. “The sea urchins can be ridiculously dense,” Konar said. Predators. The sea otter has several natural predators from which it needs to protect itself. Bald eagles, bears and coyotes will also eat sea otters. read more Leading mammalian predators of this species include orcas and sea lions, and bald eagles may grab pups from the surface of the water. Sea otters are a keystone species, meaning their role in their environment has a greater effect than other species. Sea otters, the "keystone predator" of Aleutian kelp forests, experienced dramatic population declines in the 1990's. This type of relationship between a predator (sea otter), herbivore (urchin), and plant (kelp) is known as a trophic cascade. Great white sharks and orcas will eat sea otters, especially if larger prey like seals and sea lions are not available.