The California sea hare (Aplysia californica) is among the world's largest gastropods and grows to lengths of about 41cm (16in). It has ruffled flaps along its back and two pairs of antennae. The color of an individual Aplysia californica is determined by the color of the algae (or other plant matter) on which it feeds, but in general can be shades of red, brown, or green (Source: Sabzevari).
When disturbed, Aplysia californica secretes a purple dye from glands under its mantle (see photo, courtesy Genevieve Anderson). The purpose of the dye secretion is not fully understood. Some researchers have proposed that the dye acts as an 'inky' screen or decoy to deter predators. Other researchers have suggested the dye secretion releases by-products of the sea hare's diet.
Aplysia californica has been used extensively in laboratory studies to reveal information about animal nervous systems, reproduction, and behavior. The two main behaviors studied in Aplysia californica include:
- head-waving—complex movement of the head back and forth
- inking—secretion of ink from glands along mantle (Source: Sabzevari)
Herbivorous. Algae (red, green, and brown) and eelgrass.
Classification:
- Kingdom: Animalia
- Phylum: Mollusca
- Class: Gastropoda
- Order: Anapsidea
- Family: Aplysiidae
- Genus: Aplysia
- Species: Aplysia californica
Where to See:
Occurs along most of the Californian coast and in some areas of the Gulf of California. Coastal waters where vegetation is thick; often found on seaweed where it feeds. Adults are found in shallow, tidal waters; juveniles inhabit the deeper waters where they were born (Source: Sabzevari).
References:
- Burnie D, Wilson DE. 2001. Animal. London: Dorling Kindersley. 624 p.
- Rudman WB. 1999. Aplysia californica, Sea Slug Forum. Sydney: Australian Museum. December 27, 2005.
- Rudman WB. 2003. Ink glands, Sea Slug Forum. Sydney: Australian Museum. December 27, 2005.
- Ruppert EE, Fox RS, Barnes, RD. 2004. Invertebrate Zoology. Belmont: Thomson Learning. 963 p.
- Sabzevari S. 2000. Aplysia californica, Animal Diversity Web. December 27, 2005.
