海鹿科（學名：）是海鹿總科（學名：，又名海兔超科）之下唯一的一個科。與其牠海蛞蝓相比，海鹿的體型相比較大。牠們的頭小，有著又長又圓的身體，還有長長的一對。這些物種都是一些沒有螺殻的「海螺」，一般「海鹿」會用來叫體型相對大很多的物種，而體型較小的會叫作「海兔」，但也有文獻不論大小都稱呼為「海兔」。在這些物種當中，以加州黑海兔（Aplysia vaccaria）的體型最大，也是所有腹足綱物種中體型最大的一種，經常在內容農場的「海怪」文章提及。

型態描述

Members of the Aplysiidae have an atrophied inner shell (in contrast with the nudibranchs, which have no shell at all). In Aplysia and Syphonota, this shell is a soft flattened plate over the visceral rear end, where it is fully or partially enclosed in the mantle skin. In Dolabella auricularia, the shell is ear-shaped. The shell is only present in the larval stage of the two genera Bursatella and Stylocheilus, and on this basis they have been grouped into the subfamily Dolabriferinae.

They are rather large animals. Their length can reach up to 75 cm (Aplysia vaccaria), and they can weigh well over 2 kg. They are cosmopolitan and found in temperate and tropical seas, inhabiting shallow coastal areas and sheltered bays, thick with vegetation.

The Aplysiidae are herbivorous, eating a variety of red, green or brown algae and eelgrass. Their color is diet-derived from the pigments of the algae. They concentrate the toxins found on algae.

Defenses 

Some species spout ink when disturbed or attacked, and they may also swim (rather than crawl) away, using their broad wing-like flaps or parapodia. The ink is extracted from their algal food, rather than being synthesized.

Sea hares have two main secretory glands in their mantle cavity. 
 purple gland: lying on top of the mantle cavity, above the gill. It gives off a red or purple fluid, or, in some species, a white ink.
 opaline gland: situated on the floor of the mantle cavity, beneath the gill. It gives off a white opaque secretion.

The genus Aplysia has proved useful as a model in neurobiology for the study of electrical synapses, which mediate the release of the clouds of ink.

Mating habits 

Sea hares are hermaphrodites, with fully functional male and female reproductive organs. 
The penis is on the right side of the head while the vagina is situated in the mantle cavity, beneath the shell, deep down between the parapodia. It is therefore physically impossible for mating partners to act as both male and female at the same time.

They have unusual mating habits: they can mate in pairs with one acting as a male, the other as a female, but they commonly occur in quite crowded numbers during the mating season, and this often leads to chains of three or more sea hares mating together. The one at the front acts as a female and the one at the back as a male. The animal(s) in between are acting as both males and females, in other words, the animal receiving sperm passes its own sperm to a third sea hare.

捕食者
海鹿科的捕食者包括有海蜘蛛、隆頭魚科物種及海龜。

分類學
2004年的一份研究文獻顯示海鹿科是一個單系群，由兩個支序組成：
 Aplysiinae
 Dolabellinae + Dolabriferinae + Notarchinae.

The authority of this family is still somewhat in dispute. The family was incorrectly originally spelled as Laplysiana. This was a Latinized form of the original common name "les Laplysiens" as described in Philosophie zoologique, 1:320 by Lamarck in 1809. Rafinesque introduced the new name Laplysinia in 1815. In 2001 Bouchet & Rocroi advocated the attribution of the name Aplysiidae to Lamarck.

亞科

Classification after N. B. Eales (1984):

海鹿亞科 Aplysiinae 
黃花瓣螺亞科 Dolabellinae 
Dolabriferinae Pilsbry, 1895
Notarchinae Mazzarelli, 1893

屬
 海兔属 Aplysia ：模式屬
 Barnardaclesia Eales & Engel, 1935
 Bursatella Blainville, 1817 - the only one species: Bursatella leachii Blainville, 1817
 黃花瓣螺屬 Dolabella 
 Dolabrifera Gray, 1847
 † Floribella Woodring, 1970
 Notarchus Cuvier, 1817
 Paraplysia Pilsbry, 1895
 Petalifera Gray, 1847
 Phyllaplysia Fischer, 1872
 Stylocheilus Gould, 1852
 Syphonota H. Adams & A. Adams, 1854 - the only one species: Syphonota geographica (A. Adams & Reeve, 1850)
Genera brought into synonymy
 Aclesia Rang, 1828: synonym of Bursatella Blainville, 1817
 Aplysiella P. Fischer, 1872: synonym of Petalifera Gray, 1847
 Busiris Risso, 1826: synonym of Notarchus Cuvier, 1816
 Laplysia Linnaeus, 1767: synonym of Aplysia Linnaeus, 1767
 Neaplysia J. G. Cooper, 1863: synonym of Aplysia (Neaplysia) J. G. Cooper, 1863 represented as Aplysia Linnaeus, 1767
 Phycophila A. Adams, 1861: synonym of Aplysia (Phycophila) A. Adams, 1861 represented as Aplysia Linnaeus, 1767
 Pruvotaplysia Engel, 1936: synonym of Aplysia (Pruvotaplysia) Engel, 1936 represented as Aplysia Linnaeus, 1767
 Ramosaclesia Iredale, 1929: synonym of Bursatella Blainville, 1817
 Siphonotus A. Adams & Reeve, 1850: synonym of Syphonota H. Adams & A. Adams, 1854
 Tullia Pruvot-Fol, 1933: synonym of Aplysia (Tullia) Pruvot-Fol, 1933 represented as Aplysia Linnaeus, 1767
 Varria Eales, 1960: synonym of Aplysia (Varria) Eales, 1960 represented as Aplysia Linnaeus, 1767

部分物種

參考文獻

延伸閱讀
 Kandel, E.R. (1979) Behavioural Biology of Aplysia. San Francisco, W.H.Freeman & Co. 463pp.
 Costello, M.J.; Emblow, C.; White, R. (Ed.). (2001). European register of marine species: a check-list of the marine species in Europe and a bibliography of guides to their identification. Collection Patrimoines Naturels, 50. Muséum national d'Histoire Naturelle: Paris, France. . 463 pp.

外部連結

 http://www.seaslugforum.net 
 Vue Z., Kamel B. S., Capo T. R., Bardales A. T. & Medina M. (2014). "Comparative analysis of early ontogeny in Bursatella leachii and Aplysia californica". PeerJ 2: e700 

 
Taxa named by Jean-Baptiste Lamarck