Department of Physics, Chemistry and Biology (IFM)

Environmental enrichment is a good way to decrease unwanted stereotypic behaviours and increase desired natural behaviours of zoo housed animals. A significant decrease in stereotypic swimming behaviours was seen for two of the grey seals at Kolmården Wildlife Park after the addition of the attempted environmental enrichment (treatment 1) in the mornings. Both treatments triggered important natural behaviours in the grey- and fur seals such as foraging, hunting and investigatory behaviours. These results indicate that the environmental enrichment works, promoting natural behaviours and reducing unwanted, abnormal behaviours. The response to live and dead fish was different depending on species and treatment, but overall the grey seals monopolized the treatments with dead fish, leading to the fur seals rarely getting access to it. The grey seals avoided the live fish, which was the opposite behaviour of the fur seals which chased and ingested the live fish. This shows that dead fish works as sufficient stimulation for the grey seals foraging behaviours. More studies are needed to conclude if dead fish is sufficient stimulation for the fur seals as well. The harbour seals did not participate in any of the treatments due to their caution around the other seals, and more testing arenas would possibly allow the harbour seals to gain access to the enrichments as well. One common issue for both treatments was the relatively short time it took for the seals to catch the dead and live fish, which somewhat removed the foraging aspect of the enrichment. With some minor modifications to the treatments to make it harder for the seals to see and catch the fish, as well as letting all seals have the opportunity to participate in the treatment sessions through multiple testing arenas, as well as to avoid one species to monopolize the session, both treatments can be considered good environmental enrichments for the captive grey- and fur seals at Kolmården Wildlife Park.