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Sea hare

Sea hare

Aplysia californica

Animal type
Invertebrates
Ecosystem
Rocky shore
Relatives
Sea slugs and marine snails; Phylum: Mollusca; Class: Gastropoda
Diet
Red algae, eelgrass, sea lettuce
Range
Northern California to Gulf of California
Size
Up to 16 inches (40 cm)

Meet the sea hare

The California sea hare is hermaphroditic, meaning they have both female and male sex organs. They mate in spring and summer, and sea hares find each other using chemical cues in the water. Several sea hares may congregate and form a “daisy chain,” either giving or receiving sperm. 

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Natural history

California sea hare eggs are encased in a protective sticky jelly and look like masses of spaghetti noodles. One sea hare may lay up to eighty million eggs and larvae hatch in 10 to 12 days.

The horn-like structures seen on the head of the sea hare are called rhinophores. (“Rhino” means nose, “phore” means carrier.) These rhinophores pick up chemical cues in the water, helping them find other sea hares during mating season.

Conservation

Sea hares live in the coastal rocky shore, a habitat vulnerable to the risks of coastal development and pollution such as oil spills and agricultural runoff.

Cool facts

  • Sea hares defensively release a dark purple fluid when threatened by predators. Their purple ink gets its color from a pigment in the red algae that makes up part of the sea hare's diet. 
  • A sea hare can't see like we do. Their simple eyes can only tell light from dark.
  • California sea hares have a secret internal shell encasing their vital organs

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