In Osnabrück zoo, the opening of a new Sumatran tiger enclosure, an extension to the former tiger facility, took place in March 2014. Installed in the new enclosure were two young tigers and they were observed in the first weeks after their arrival. The focus was on the use of the enclosure and the tigers approach to each other. In addition, their general behaviour was recorded and examined to see whether they developed any stereotypical behaviour types.Data collection took place from 25th March to 11th July 2014 (in total 120hours of observation, 60hours per tiger). The animals were observed by focus animal sampling. The central focus of the observations was laid on stress indicating behaviour and approaches to each other.At the beginning, the female tiger (Diana) showed some stereotypic behaviour (pacing), but this was not established and vanished after a few weeks.Following introduction into the outdoor enclosure, the tigers interacted mostly in friendly ways. There is no indication that one tiger was overly active in approaching the other, as expressed by approach-leave-coefficient.