Source Paper
The role of flower consumption in Howler Monkey Females’ diet: adjustment across reproductive states
Gisbrecht A, Aristizabal JF, Rodríguez-Landa JF, Hernández-Salazar LT
PeerJ • 2026
Feeding Behavior Observation
Objective: To observe and quantify feeding behavior in mantled howler monkeys, measuring time invested and food intake across different lactation states and food categories
Protocol Steps
Observation scheduling
Collect data every month for 10-20 days throughout the month from sunrise for 5 hours
View evidence from paper
“Female behavior was collected every month for 10–20 days throughout the month, when possible (except for December and January), from sunrise and the following 5 h”
Individual identification
Identify females using pelage coloration and physiological features
View evidence from paper
“The females were identified by means of pelage coloration and certain physiological features”
Lactation state classification
Classify females into early lactating (birth to 3 months), late lactating (offspring increasingly independent), or non-lactating stages
View evidence from paper
“EL was determined through the presence of a dependent offspring (birth to three months) carried mostly ventrally by the mother”
Feeding behavior recording
Record time invested in seconds and food intake in grams for different food categories
View evidence from paper
“We recorded the time invested (seconds) and food intake (grams) of the items consumed by the females”
Food intake rate calculation
Record number of discrete food units consumed during feeding session and multiply by simultaneous group feeding time
View evidence from paper
“we recorded information on the number of discrete food units ( i.e., individual items or batches of items in 1-minute bite-rate) consumed during a feeding session”
Food sample collection
Collect consumed and dropped fruits or fruits in same condition, and leaf/flower samples from feeding trees
View evidence from paper
“we first collected all consumed and dropped fruits or fruits in the same condition as consumed from that tree”
Sample drying
Dry leaves using cardboard box with 60W bulb, dry fruits and flowers in food dehydrator at 35°C
View evidence from paper
“leaves were dried in a cardboard box using the heat of a 60 W light bulb, and fruits and flowers were dried in a food dehydrator set at 35 °C”