Induction of Natural Nursing Behavior in Eurasian otters through Recreation of Wild Habitat in the Exhibition Enclosure

Abstract

Aquamarine Fukushima started keeping Eurasian otters in 2010 and succeeded in breeding them eight times. The exhibits was renovated in 2015 to recreate natural habitat of wild otters. Novel planting technique was employed for waterweeds and land plants to prevent the otters from damaginge them easily. In order to exhibit otters with fish, tests were conducted to determine which fish species shows a high survival rate. Consequently, we made the new enclosure’s environment as natural as possible for the otters. Furthermore, new breeding and nursing behaviors never seen before in captivity were observed, as described below. 1) In the old enclosure, the dam gave birth in a nest that she usually used. However, in the new enclosure, the dam used several nests prior to parturition and gave birth in a nest that she did not typically use. 2) In the old enclosure, the dam used only one nest during the nursing period. Meanwhile, the dam carried the pups and changed nest frequently in the new enclosure. Nest selections were also affected by the weather. 3) Wild Eurasian otters usually defecate in water during the nursing period. The dam defecated on land and in water in the old enclosure, but in the new enclosure, the mother defecated only in water. These new behaviors were also observed in wild otters in Europe. Therefore, it is probable that these natural behaviors were induced from the availability of multiple options for a nest and the diverse environment of the new enclosure.