The Wildlife Trust of India has taken a long term responsibility to identify a suitable habitat for the threatened families of Eastern Hoolock Gibbon from a village called Dello in Arunachal Pradesh to a nearby forested area which was the earlier home of this species. There is an ongoing successful rescue and translocation programme since November, 2011 in which four Eastern Hoolock Gibbon families comprising 11 individuals were translocated in three different habitat types in and around the forested area of the Mehao Wildlife Sanctuary. Post-release monitoring is an obvious and required technique to study the rescued families of Eastern Hoolock Gibbons after translocation to confirm their post-release survival and better livelihood. The regular monitoring of the activity patterns has helped to understand the habitat utilization and resource use in the newly released sites. Along with the rescue operation, there is an additional task to find out the potential habitats to define as ideal release sites for gibbons. The post release monitoring was studied through the instantaneous scan sampling method to collect the information mostly about their activity patterns. The present study describes the overall activity patterns and resource use in the released gibbons on the basis of utilization of different habitat types. It was observed that the ranging pattern was mostly influenced by the resource availability and forest type. The gibbon family released in the denser forest habitat developed a general food habit whereas the family from the thinner forest area became the specialist consumer. However, further detailed study with sufficient data is required to comment on their general ecology.