MO3 D03

Howler_3_Kathy Slater smaller

General Information for the case study: if you would like access to this data set, please email your country office via the contact page

WRL reference M03 D03
Module M03 Animal Behaviour
Data Set D03 – Howler monkey vocalisation
Research questions
  1. Howler monkeys can determine how many males are in each group based on the number of males that join in the loud calls made by their group. Can you correctly identify the number of males in each group based on their calls?
  2. Are females with infants more likely to be vigilant in response to loud calls than females without infants?
Keywords behaviour; fitness; selection; social behaviour; territory; primates; rainforest; reproduction
Potential Curriculum links AP Biology 2.E.2, 2.E.3
AP Env Sci II The Living World A-E, III Population A
IB Biology 5.2, A.4, A.6
IB Ess N/A
AQA 3.4.6, 3.4.7, 3.7.4, MS, AT, PS
edexcel A – 4.3, 5.1, 5.3, B – 10.1, Maths A
OCR A –4.2.1, 6.3.1, 6.3.2 – M, PAG, HSW
SQA FH2J 2 (b) (i)  (iii), HOAL 2(a)(b)(i)(c)
CCEA  4.4.3
WJEC C1-5, C2 -1, C3-3, App B, Pract.req.
Summary

This primate population of Howler monkeys is located in a forest near Rancho Manacal in Honduras.  Howler monkeys have high infanticide levels (64%) due to incoming males systematically killing infants in the group. Howler monkeys are well known for their vocalisations which serve a number of purposes from territory defining to an assessment by bachelor male groups of the competition from other males when attempting to take over an existing group.  Females with infants are said to be very sensitive to these male calls!

This study analyses vocal data to assess the number of males making the calls.  Data from long-term observations of ‘non-mother’ and ‘mothers with young’ behaviour are looked at to show evidence that females with young are more vigilant when listening to calls from male groups.

Graphs are plotted after processing the behavioural data.

Difficulty:

Research Q1 – 6/10

Research Q 2 – plotting graphs and discussion 8/10