environmental
alone
animal
annoyed
anthropoid
ape
baby
bars
behind
being imprisoned
cage
caged
captive
captivity
captured
cell
chimp
chimpanzee
conservation
depressed
exhibit
expression
fear
gorilla
hang
human
iron
jail
locked
lonely
mammal
monkey
muzzle
natural
nature
poor
primate
prison
sad face
sadness
simian
stress
suffering
tame
upset
wild
wildlife
young
zoo
zoological