Like our seahorses, these herbivorous marine mollusks are produced through aquaculture. In the wild they are part of the marine coastal community in the Pacific Ocean from northern California to Baja California. Individuals can often be found on their algal food, and aggregate in large numbers near food in the summer months (June - August) when they breed.
The name "sea hare" comes from the sensory tentacles on the top of their head, called rhinophores, which are somewhat reminiscent of rabbit's ears. Unlike other gastropods, sea hares don't have a large external shell in which to retreat. Instead, they have a small, flat, vestigial shell, the consistency of cardboard, covering the viscera and nominally protecting the heart and other internal organs.
More than just an ocean oddity, sea hares have the potential of benefitting humankind. IN 2000, Dr. Eric Kandel won the Nobel Prize in Physiology or Medicine for research into how neurons form and store memories. For this research, he used neurons from sea hares and mice. Other studies of sea hares have led to drugs now in clinical trials aimed at reversing memory loss in patients with degenerative mental diseases. In other words, drugs currently being tested to reverse Parkinson's disease and Alzheimer's have been developed thanks to the humble California Sea Hare!