The subjects in this study were seven South African fur seals (Arctocephalus pusillus pusillus), three harbour seals (Phoca vitulina) and three Baltic grey seals (Halichoerus grypus baltica). All seals resided at Kolmården Wildlife Park in a public display exhibit called "Brådjupet". It consists of an 800 m² pool, shaped by natural granite rocks, and includes an underwater canyon with a depth from 2.5 m to 9 m, and a shallow area with an average depth of 2-3 m. In the middle of the exhibit, there is a rock, creating an island. At the deep end there are underwater viewing panels, four close to the bottom and four close to the surface. The seals were kept outside all year around with access for the fur seals to indoor quarters.