Nicotinic receptors exist in a wide range of organisms, from sea slugs to mammals.

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However, the researchers were surprised to discover that just 24-hours later, the sea slugs had regenerated their male organs and were able to mate again.

BBC: Sea slug's 'disposable penis' surprises

When she favoured the cheapest of three suggested menus, British diplomats warned that delicacies like shark's fin and sea slugs "would be conspicuous by their absence".

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He carried the baton a bit farther by looking at the biochemical changes involved in the formation of memory first (because such experiments are unethical in people) in sea slugs, and then in mice.

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Closer examination of the animals' anatomy revealed that the sea slugs had a large part of their penis coiled up in a spiral inside their bodies, which they would then use to replenish their missing part.

BBC: Sea slug's 'disposable penis' surprises