The sea urchin are round, underwater animals belonging to the class Echinoidea. Their name originates from an Old French word “herichun” which used to pertain to the land-dwelling hedgehog. In other words, a sea urchin is essentially a sea hedgehog, sporting spines all around its body to protect it from would-be predators.
The spines are especially useful for deterring predators due to their sharp, pointed tips laden with venomous liquid. Many fish have fallen victim to seemingly unassuming but rather deadly defenses. There are, however, some predators with an anatomical adaptation that make them better hunters of these hardy urchins.
As such a unique group of animals, these are intriguing predators that highlight how animals in nature adapt to their environment in order to survive. Here are the top predators of sea urchins that give them a run for their lives.
List of Sea Urchins Predators
Crabs are crustacean animals belong to the infraorder Brachyura that can both thrive on either marine or land environments. Possessing a sturdy exoskeleton made up of mineralized chitin, these animals are particularly adept at surviving harsh environments. They are also quick and mobile, able to ably walk in a sideways manner owing to their specialized legs.
What sets the crab apart as a predator of sea urchins, however, is its powerful pair of pincers. Alternatively called a chela, these are considered legs of the crab with a specialized function. They use these effectively to feed and defend.
With their sturdy shells and powerful pincers, fresh crabs are well-equipped to deal with defenses of the sea urchin. Once it has taken its hold using its claws, the crab can easily crush the exterior body of the sea urchin.
Lobsters are marine crustaceans belonging to the family Nephropidae. These animals have elongated bodies that are completely covered in a sturdy exoskeleton, meant to protect them from potential attackers. On top of that, these sea urchin predators also have characteristic claws over their front legs used for defending themselves and hunting.
These powerful claws are called pereiopods. Many lobsters will have asymmetric claws, with one these being larger and more powerful called the “crusher”. With rounded irregularities over the pincer claws, these are specially made for crushing their prey. The other claw possesses serrated edges meant for tearing through the prey.
Like the Fresh Crabs, Lobsters are rendered immune to the venomous spines of the sea urchin due to their chitinous exoskeleton. This leaves the lobsters free to grasp the sea urchins with their powerful pincers and overcome the hard shell protecting the internal organs of the sea urchin. Truly, the sea urchin is no match for this predator.
The triggerfish pertains to a large group of brightly colored fish from the family Balistidae usually found in tropical oceans but much greater numbers in the Indo-Pacific. The triggerfish is an aggressively predatory fish. They are also believed to possess a higher level of intelligence for a fish and can discern from previous mistakes. Apart from these, they have a strong-jawed mouth with teeth that are particularly specialized to overcome hard shells.
Triggerfish are one of the common predators of sea urchins and other related bottom-dwelling marine animals. With their highly aggressive nature, a triggerfish can easily overwhelm the sea urchin’s defenses. They can individually pick apart the defensive spines of the sea urchin until they can bite directly into the sea urchins body.
4. California Sheephead
California sheephead are a species of brightly colored fish endemic to the Pacific Ocean. Famously seen in the Gulf of California, these fishes are hermaphrodites and all are born female first. As they develop and morph into males, they also transform to develop a characteristic large black-colored head and black tail.
They are carnivorous fish preferring to forage for food along the seabeds. Sea urchins are arguably their most common prey. The California sheephead possesses a formidable set of chitinous teeth and powerful jaws that can crush the sear urchins body within their mouths. They are so powerful, even crabs and other crustaceans number among their other preferred prey.
5. Wolf eels
The wolf eel is a marine animal endemic to the North Pacific Ocean belonging to the order Perciformes. Wolf eels can measure up to seven feet long and usually stay in pairs as mates in rock dens underwater.
The wolf eel is one of the most visually intimidating underwater predators. They possess a horrifyingly disturbing face with a blank menacing look. They get their threatening name from their powerful jaws and sharp teeth for eating and hunting its prey.
Sea urchins, including crabs, are frequently part of the wolf eel’s diet. The eel’s jaws are large enough to accommodate the entirety of a sea urchins body. These predators of sea urchins then proceed to crush their outer body with its powerful bit and sharp teeth. Even crabs or lobsters with hard shells can be crushed with its powerful jaws. Sea urchins beware!
6. Sea otter
The sea otter is a marine mammal belonging to the weasel family of animals, specifically the Family Mustelidae. They are endemic to the North Pacific Ocean and are considered one of the smallest of marine mammals. They can live both on land and in the water but almost utterly prefer to live in the ocean.
They are carnivorous animals preferring to feed on mollusks, crustaceans, and sea urchins. Their physical make-up includes webbed feet, strong legs and a powerful tail to propel him quickly underwater as he hunts for prey. Once he’s identified his game, he can use his powerful incisor teeth to cut the sea urchins into smaller pieces for eating.
The sea otters, owing to their agile and crafty nature, can make short work of sea urchins and are considered a primary sea urchin predator. These animals are peculiar in that they are the only animals in this list that use tools such as rocks to break open the shells of sea urchins. They are so effective that certain countries have made use of these animals to control the overpopulation of sea urchins in certain ecosystems.
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