Mystery over rare sea slug found washed up on UK beach

The rare creature was found by a dog walker (Picture: Daily Post)

A giant marine slug was found beached in Anglesey by a dogwalker, baffling some experts.

The bizarre creature was later identified as a sea hare, a marine snail more commonly called a ‘sea slug’.

Smaller sea hares are native to the UK, but the Trearddur is thought to be a much rarer creature, usually found in the Mediterranean.

Emma Leese came across the sea hare some 20 metres from the water’s edge at low tide. Worried that local dogs might take too much of an interest, she returned it to the sea.

‘When back in water, it sort of unfolded,’ she said. ‘It began wriggling – slug-like – and its stalks began going back up.’

As sea slugs cannot absorb atmospheric oxygen, they typically die relatively quickly after stranding.

When di...