Fifty years ago hedgehogs were reportedly let go into a garden in South Uist in the hope they would eat slugs and snails. But numbers multiplied - and they were soon preying on more than garden pests.

Psychedelic hedgehogs, purple pineapples ... Watching a nudibranch eat isn’t, at first glance, all that different from watching a slug on a leaf. But if the nudibranch is feeding on a venomous ...