Sea hares are related to nudibranchs but are classed within the family of Aplysiidae. The Sowerby's Sea Hare (Aplysia Sowerbyi) is a fairly common sighting in Sydney, especially at night and in the harbour. They are quite large, and often can be seen about as long as a brick. They are beautiful when swimming. They have long rhinophores on their head, which make them look a little like a rabbit.