These are the most frequently used words in this book.
1991
1993
1994
adolescent
adult
age
al
among
animals
apes
area
behavior
between
borneo
captive
cases
conservation
contact
copulation
data
days
density
development
during
ed
estimates
et
even
females
field
figure
first
food
forest
galdikas
great
group
habitat
however
human
individuals
indonesia
interactions
juvenile
level
life
male
may
mean
must
national
natural
nature
nests
new
number
observed
orangutans
park
period
phase
population
pp
press
primate
problems
range
rehabilitation
relationships
reproductive
research
results
rijksen
samples
see
sexual
should
sign
social
species
study
subadult
subject
sumatra
system
table
tests
time
total
towards
trial
two
use
used
value
van
wild
years
york
zoo