This American lobster, which has spent the summer in Newfoundland’s Petty Harbour Mini Aquarium before being re-released back into the ocean, certainly has something unusual going on.

If you have ever seen a live lobster – either in the ocean or is a shop or restaurant where it is destined to become someone’s dinner – then you will know that they are for the most part they are a dark blue, even murky brown colour. But here we have some bright yellow claws. So what’s going on?

Lobsters get their colour from pigments – particularly one called astaxanthin – a red-orange coloured chemical which is in the food that they eat. The astaxanthin ends up stored in the skin of the lobster, which is under that hard, outer shell. Over time, the astaxanthin makes its way into the shell where it interacts and binds to a protein complex with… well, an equally complex name – crustacyanin. The result of this interaction is the dark blue or murky brown colour we are so familiar with. In the case of golden claws here, he has a genetic mutation that changes the production of the crustacyanin protein. Essentially the mutation suppresses other colours that give the lobster its usual dark murky colour.

Old Golden Claws here isn’t alone in being an American lobster with a genetic mutation altering colouration. Other American lobsters have been spotted with interesting colours, including a half-brown, half-orange one, a bright blue one, and even a super-white one!

Now if Golden Claws here ended up in the cooks' pot, she (or he – I am not sure what sex it is) would turn bright red just like every other lobster (except for the all-white ones – there are always exceptions) facing the same end. A few years back, an international team of scientists led by University of Manchester’s Professor John Helliwell figured out exactly why they do this. Yep – it’s back to astaxanthin.

When the lobster is cooked, the crustacyanin protein goes through a process known as denaturing, which breaks down the protein and releases the astaxanthin giving… red lobster!