Hoolock gibbons  (Hoolock hoolock and Hoolock leuconedys)

Male and female western hoolock gibbons
Male and female western hoolock gibbons
© Brij Kishor Gupta
Female western hoolock gibbon in tree
Female western hoolock gibbon in tree
© Elio Della Ferrera / naturepl.com
Female western hoolock gibbon
Female western hoolock gibbon
© Stanley Breeden / www.osfimages.com
Female western hoolock gibbon hanging in branches
Female western hoolock gibbon hanging in branches
© Elio Della Ferrera / naturepl.com
Western hoolock gibbon female in canopy
Western hoolock gibbon female in canopy
© Bernard Castelein / naturepl.com
Western hoolock gibbon male in canopy
Western hoolock gibbon male in canopy
© Bernard Castelein / naturepl.com
Female western hoolock gibbon calling
Female western hoolock gibbon calling
© Stanley Breeden / www.osfimages.com
Male western hoolock gibbon calling
Male western hoolock gibbon calling
© Mandal Ranjit / www.nhpa.co.uk