The groups are usually nuclear families, but can be extended families. These tamarins are territorial and defend their area with scent markings and vocalized threats. Some signs of aggression are an open mouth, an arched back and staring. Golden lion tamarins groom themselves much like other primates. Mainly the males groom the females.
Adults spend a lot of time grooming and huddling.
The juveniles play a lot. They chase each other around and wrestle. They have a quad-gait, meaning they use all fours to get around. They run and walk through the trees and spring and leap between branches and vines. Even though they have very long tails, nothing has been discussed regarding if they use them to swing from or not.