Featured Creature

One of the most popular and most photographed exhibits at the Monterey Bay Aquarium is the beautiful mesmerizing ballet of sea nettles. The Pacific sea nettle, Chrysaora fuscescens, lives in coastal waters from Alaska to California, to Japan, Kamchatka, the Aleutian Islands, and the Bering Sea. With their long, trailing tentacles these jellies are large: their bells are about 17.7 inches (45 cm) in diameter, mouth-arms from 12 to 15 feet (3.6 to 4.6 m) long. The frilly mouth-arms and tentacles are covered with stinging cells, called nematocysts.

Boris is a famous missing link in the evolution of chordates: he’s an early tetrapod (tetrapod means “four-legged”) fossil. Paleontologist Jenny Clack was so excited when she uncovered him that she named him Boris. Boris is a missing link because he represents an animal who may have been the first of its kind to make the transition from life in the sea to life on the land. This invasion of the land by vertebrates was a key moment in evolutionary history, leading to colonization of the land by four-limbed animals.

Krill are shrimp-like arthropods that make up a large portion of the zooplankton in many regions of the ocean. Krill are near the base of the oceanic food web feeding on phytoplankton. In turn, enormous swarms of krill feed the largest creatures in the ocean: blue and other baleen whales, sea birds, squid, and fish.

Blue whales, the largest animals that ever lived, eat up to four tons of krill a day to fuel their huge bodies. In fact, krill – about two inches long –make up the majority of their diet. Blue and humpback, and other baleen whales, are filter feeders. They take in huge gulps of seawater dense with krill straining out the water though their baleen and then swallowing their catch.

Imagine a creature with such a radically different body plan that we, bilateral humans, can’t really fathom how they have been so successful. Sea stars, and other echinoderms, move and feed like no other animals. They are animals that followed a different evolutionary path after evolving from the same bilateral ancestors as us.

Many still call sea stars “starfish”, but they certainly aren’t fish. No head, no tail, all arms –sea stars are just that: stars. Based on five-part radial symmetry (though some sea stars have many more arms), key functions are coordinated in the center of their bodies, then passed down the arms. The sea star has no brain, but a nerve ring in its center, like a relay station that coordinates the movement of its arms. This nervous system relays impulses from light, touch and chemical sensors around its body.