The secondary adaptation of Cetacea to a fully marine lifestyle raises the question of their
ability to maintain their water balance in a hyperosmotic environment. Cetacea have access
to four potential sources of water: surrounding salt oceanic water, dietary free water,
metabolic water and inhaled water vapour to a lesser degree. Here, we measured the
18O/16O oxygen isotope ratio of blood plasma from 13 specimens belonging to two species
of Cetacea raised under human care (four killer whales Orcinus orca, nine common …

Determination of water balance in Orcinus orca and Tursiops truncatus using oxygen
isotopes. - MNHN - Muséum national d'Histoire naturelle …