Alex Mustard / Hooded nudibranchs (Melibe leonina) filter feeding beneath bull kelp. Hussar Point, Browning Pass, Port Hardy, Vancouver Island, British Columbia, Canada.

Norbert Wu / Lion Nudibranch (Melibe leonina) group on kelp blade with hoods extended as they feed in the ocean current, Vancouver Island, British Columbia, Canada

Norbert Wu / Lion Nudibranch (Melibe leonina) group on kelp blade with hoods extended as they feed in the ocean current, Vancouver Island, British Columbia, Canada

Norbert Wu / Lion Nudibranch (Melibe leonina) with hood extended as it feeds in the ocean current, Vancouver Island, British Columbia, Canada

Hiroya Minakuchi / Lion Nudibranch (Melibe leonina) feeding, California

Fred Bavendam / Lion Nudibranch (Melibe leonina) pair and egg ribbon clinging to eel grass, Quadra Island, British Columbia, Canada

Juergen Freund / Lion nudibranch {Melibe leonina} Pacific, Canada

Juergen Freund / Colonial lion nudibranchs {Melibe leonina} on kelp Pacific, Canada

Juergen Freund / Colonial lion nudibranchs {Melibe leonina} on kelp plants, Canada, pacific

Fred Bavendam / Lion Nudibranch (Melibe leonina) with hood extended as it feeds in the ocean current, Vancouver Island, British Columbia, Canada

Fred Bavendam / Red Rock Crab (Cancer productus) eating a Lion Nudibranch (Melibe leonina), Vancouver Island, British Columbia, Canada

Juergen Freund / Colonial Lion nudibranch mouth, Canada, Pacific ocean

Juergen Freund / Colonial Lion nudibranchs amongst kelp, Canada, Pacific coast

Juergen Freund / Colonial Lion nudibranch, Canada, Pacific coast

David Fleetham / Lion / Hooded nudibranch (Melibe leonina) and its eggs on eel grass, British Columbia, Canada.

Norbert Wu / Lion Nudibranch (Melibe leonina) with hood extended as it feeds in the ocean current, Vancouver Island, British Columbia, Canada

Hiroya Minakuchi / Lion Nudibranch (Melibe leonina) feeding, California

Hiroya Minakuchi / Lion Nudibranch (Melibe leonina) feeding, California

Alex Mustard / A huge, seasonal gathering of Hooded nudibranchs (Melibe leonina) on Bull kelp (Nereocystis luetkeana) in a sheltered bay, Browning Pass, Vancouver Island, British Columbia, Canada, Queen Charlotte St...

Alex Mustard / A huge, seasonal gathering of Hooded nudibranchs (Melibe leonina) on Bull kelp (Nereocystis luetkeana) in a sheltered bay, Browning Pass, Vancouver Island, British Columbia, Canada, Queen Charlotte St...

Shane Gross / Lion nudibranch (Melibe leonina) on Eelgrass (Zostera marina), Prince William Sound, Alaska, USA, Pacific Ocean.

Shane Gross / Lion nudibranch (Melibe leonina) on Eelgrass (Zostera marina), Prince William Sound, Alaska, USA, Pacific Ocean.

David Hall / Hooded nudibranchs (Melibe leonina) clinging to Bull kelp (Nereocystis luetkeana) as they slowly open and close their oral hoods to catch plankton at night, Nigei Island, Queen Charlotte Strait, Briti...

David Hall / Hooded nudibranchs (Melibe leonina) with oral hood for catching planktonic prey. In the Pacific Northwest they are often found clinging to bull kelp (Nereocystis luetkeana). Nigei Island, Queen Charlo...

David Hall / Hooded nudibranchs (Melibe leonina) clinging to bull kelp (Nereocystis luetkeana) at night split level sho, . Nigei Island, Browning Pass, Queen Charlotte Strait, British Columbia, Canada. September.

David Hall / Hooded nudibranchs (Melibe leonina) clinging to the kelp (Nereocystis luetkeana) split level shot. Nigei Island, Queen Charlotte Strait, British Columbia, Canada. September.

David Hall / Hooded nudibranchs (Melibe leonina) clinging to the kelp (Nereocystis luetkeana) split level shot. Nigei Island, Queen Charlotte Strait, British Columbia, Canada. September.

David Hall / Helmet crab (Telmessus cheiragonus) and Hooded nudibranchs (Melibe leonina), Nigei Island, Queen Charlotte Strait, British Columbia, Canada. October.

David Hall / Hooded nudibranchs (Melibe leonina) clinging to Bull Kelp (Nereocystis luetkeana). Nigei Island, Queen Charlotte Strait, British Columbia, Canada. September.

David Hall / Hooded nudibranchs (Melibe leonina) on Bull Kelp (Nereocystis luetkeana). These unusual nudibranchs possess an 'oral hood' which is used to capture plankton. Nigei Island, Queen Charlotte Stra...

Magnus Lundgren / Lion's mane nudibranch (Melibe leonina) photographed at night, God's Pocket, Vancouver Island, Canada. Magnus