Whether it's an attack by another marine creature, or disorientation in a noisy ocean, there are various reasons for marine mammals to wash up on the shoreline. So how do we find out the cause of each stranding? The Scottish Marine Animal Stranding Scheme (SMASS) undertakes forensic investigations into strandings around the Scottish coast. Its work complements marine mammal research at institutes like SAMS and helps to piece together what's happening in the unseen underwater world. In this episode, we meet Dr Andrew Brownlow of SMASS and Prof Ben Wilson, a marine mammal expert at SAMS, to discuss how investigations are carried out and why strandings might happen. They also reveal the surprising culprit behind the disturbing 'porpicide' events that see badly injured harbour porpoises wash up on beaches around the world.    The Ocean Explorer podcast is produced by the Scottish Association for Marine Science (SAMS), an ocean research institute and partner of UHI based in Oban. In each episode, we take a deep dive into marine science topics with SAMS scientists and special guests. Interested in working or studying with us, or helping with our work? Visit www.sams.ac.uk to find out more.