Some Antarctic sea spiders grow huge while breathing only through their skin
Most sea spiders are tiny, but species in the cold waters around Antarctica can reach a leg span of over 70 centimetres despite having no gills or lungs, absorbing oxygen by diffusion straight through their leg surfaces. Researchers tested whether oxygen-rich polar water was what made this size possible, but found performance barely dropped under low-oxygen conditions, undercutting the leading explanation for polar gigantism.