Mollusca · mollusks

California sea hare

Aplysia californica

Aplysiidae · sea haresIUCN: Not evaluated
California sea hare
Photo: Genny Anderson · CC BY-SA 4.0 · Wikimedia Commons · resized

A large sea slug that releases purple ink when disturbed.

Fun factEric Kandel's Nobel Prize-winning memory research used this sea hare's large neurons.

Waters
Eastern Pacific
Depth zone
Coastal shallows & estuaries
Diet
Red & green algae
Size
Up to 75 cm when fully stretched

Classification

Mollusca › Gastropoda › Aplysiida › Aplysiidae

  1. Kingdom Animalia animals
    • Many-celled organisms that eat other living things for energy (heterotrophs)
    • Cells have no cell walls
    • Most can move at some stage of life
  2. Clade Bilateria bilateral animals
    • Body has a left and right side that mirror each other (bilateral symmetry)
    • Head end with concentrated nerves; three tissue layers
    • Includes about 99% of all living animal species
  3. Clade Protostomia protostomes
    • In the embryo, the first opening usually becomes the mouth
    • Main nerve cord runs along the belly (ventral)
    • Includes mollusks, worms, and arthropods
  4. Clade Spiralia mollusks, worms & kin
    • Embryos usually divide in a spiral pattern (spiral cleavage)
    • Many have a swimming larva with a band of cilia (trochophore)
    • Includes mollusks and segmented worms
  5. Phylum Mollusca mollusks
    • Soft body with a muscular foot and a fold of tissue (mantle) that makes the shell
    • Most have a rasping, tongue-like ribbon of teeth (radula)
    • Includes snails, clams, octopuses, and chitons
  6. Class Gastropoda snails & slugs
    • Snails and slugs, most with a single, often coiled shell
    • Body twists 180 degrees during development (torsion)
    • Crawl on a broad muscular foot
  7. Subclass Heterobranchia sea slugs & kin
    • Includes most sea slugs, sea hares, and land and freshwater snails
    • Many marine members have reduced or no shell
  8. Order Aplysiida sea hares
    • Sea hares: large slugs with ear-like head tentacles (rhinophores)
    • Internal remnant of a shell; release ink when disturbed
  9. Family Aplysiidae sea hares
    • Graze on seaweed
    • Large nerve cells made them a model for memory research
  10. Genus Aplysia
    • Species in the same genus are very close relatives and often look alike.
  11. Species Aplysia californica California sea hare

Closest relatives in the guide