Common threshers are active, strong swimmers, with infrequent reports of them leaping completely out of the water.[17] Like the fast-swimming sharks of the family Lamnidae, the common thresher has a strip of aerobic red muscle along its flank that is able to contract powerfully and efficiently for long periods of time.[18] In addition, they have slow-oxidative muscles centrally located within their bodies and a blood vessel countercurrent exchange system called the rete mirabile ("wonderful net"), allowing them to generate and retain body heat.