Not satisfied with your eight arms, which used to be a tiny worm’s lophophore, you use the muscles which used to hold on to your two ‘valves’ or shell parts to grab hold of your prey. They get longer and longer, until eventually they are what we call tentacles. You can now hunt quite effectively, swimming in the deep water until you see food, then shooting out your long tentacles to grab it and pull it within reach of your arms. Then it gets wrapped up and pulled in until it is eaten.

There are two hunting techniques that will determine your next stage… quickly chasing down your prey, or pursuing it till you wear it out. Fast or slow? Sprinter or jogger?