Giant green anemone
Anthopleura xanthogrammica
- On view
- Kelp Forest, Rocky Shore
- Animal type
- Invertebrates
- Ecosystem
- Rocky shore
- Relatives
- Hydroids, corals, jellies; Phylum: Cnidaria; Class: Anthozoa
- Diet
- Detached mussels, crabs, small fishes
- Range
- Alaska to Panama
- Size
- Crown up to 7 inches (17.8 cm) in diameter; tentacles up to 9.8 inches (25 cm) in length
Meet the giant green anemone
The adult giant green anemone is sessile, rarely moving from the spot where it attaches early in life. Although its gets some of its green color through natural pigmentation, much of its color is gained from the symbiotic relationship it has with the microalgae (zoochlorellae) and dinoflagellates (zooxanthellae) that live in its tissues. These unicellular organisms are photosynthetic, providing the giant green anemone with beneficial nutrients as well as pigmentation.
Natural history
Although the giant green anemone is considered a solitary animal, it can often be found in groups as dense as 14 anemones per square meter (~11 square feet). These anemones are carnivores, feeding on crabs, mussels, small fishes and sea urchins. They have been known to settle into mussel beds for easy access to a sustainable food source.
Like other cnidarians, the giant green anemone uses the nematocysts (stinging cells) found on its tentacles to paralyze its prey. It then uses its tentacles to bring the food to its mouth.
Conservation
Though it may look rugged, the rocky shore habitat is fragile. Rocky shore creatures like the green anemone are at risk from coastal development and pollution (including waste oil and agricultural runoff). Some tide pools are also in danger of being “loved to death” by visitors.
Tread lightly as you explore tide pools to avoid crushing plants and animals, and never take creatures from their habitat.
Cool facts
- The pharmaceutical industry uses a compound from the giant green anemone as a beneficial heart stimulant for humans.
- Some fishes develop resistance to the giant green anemone’s sting by covering themselves with mucus.
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