Fascinating Fact
Sea anemones look like flowers but are animals, and they use stinging cells on their tentacles to catch small prey.
Sea invertebrates are animals without backbones, and they make up most marine species. You can find them clinging to rocks, burrowing in sand and mud, drifting in the water column, or hiding in seaweed and reefs. Many are identified by body shape, shells, spines, legs, and the way they move, such as crawling, swimming, jetting, or filtering food from seawater.
Key Terms
- Invertebrate: An animal without a backbone.
- Exoskeleton: A hard outer covering that supports and protects the body, common in crabs and lobsters.
- Filter feeder: An animal that eats by straining tiny food particles from water.
Frequently Asked Questions (Click to see answers)
What is a marine invertebrate?
A marine invertebrate is an ocean animal that has no backbone. This group includes creatures such as crabs, starfish, mussels, squid, worms, and many types of plankton.
What are common examples of sea invertebrates?
Common sea invertebrates include crabs and shrimps, snails and clams, starfish and sea urchins, jellyfish, sponges, and octopus or squid. They live from shorelines to deep seas.
How do sea invertebrates protect themselves?
Sea invertebrates may protect themselves with shells, spines, tough skin, camouflage, or hiding in crevices and sand. Some release ink or mucus, and many rely on staying still to avoid detection.
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