In summer one can see black gibbons (HYLOBATES CONCOLOR GABRIELLAE) (PONGIDAE) on islands of the pond. They usually swing among specially arranged metal rods and ropes. Gibbons avoid water, so they are safely isolated on island. For night and in cold weather they shelt in a small warm house. Gibbons move primarily by brachiation when the long and very strong arms suspend and propel the body with surprising agility through trees. Males of this species are black and females are golden. Loud calls or songs of gibbons are remarkable and the vocalisations of the male and the female differ. In the wild loud vocalisations of a pair of gibbons help them to defence their home range. In autumn our gibbons are transferred to warm enclosures of "Primate House".