Homework - Alarm calls of capuchin monkeys
Part 1
View video clip C: Capuchins calling. How do capuchin monkeys react to predators? (1
minute 12 seconds).
http://www.educationscotland.gov.uk/highersciences/biology/unitthree/interrelationships/primate
behaviour.asp
Part 2
Read the following article and answer the questions that follow.
White-faced capuchin monkeys (Cebus capuchinus) live in tropical forests in Central and
South America, see Figure 1. They are medium-sized monkeys (with a mass of 2.5–3.5 kg)
and live in groups. They spend most of their time in the trees (termed arboreal) but do come
down to the ground occasionally to drink and look for food. Their diet is varied and they
eat both plant and animal food.
They are preyed upon by a number of animals as they move around the f orest, so they keep
watch for predators. The predators might be humans, birds (like eagles, falcons and owls),
large cats (like jaguars), snakes (like boa constrictors) and caimans (which are like
alligators). If a capuchin sees a predator it gives an alar m call to warn others in the group.
Capuchins give a different alarm call for each predator. Scientists recorded these alarm
calls to see if the different calls had some features in common and published their results in
a scientific journal.*
*Fichtel, C., Perry, S. and Gros-Louis, J. (2005) Alarm calls of white-faced capuchin
monkeys: an acoustic analysis. Animal Behaviour, 70, 165–176.
Questions
1.
White-faced capuchins live in tropical forests and eat fruit, insects, eggs, etc. Are
capuchins herbivores, carnivores or omnivores?
(1)
2.
Capuchin monkeys have a number of predators, which are aerial, arboreal or
terrestrial. Where does an aerial predator hunt from? Underline the correct answer.
(1)
(i)
(ii)
(iii)
(iv)
(iv)
3.
Trees
Ground
Air
Underground
Water
Humans are one of their predators. Underline which type of predator they are.
(1)
(i)
Aerial
(ii) Arboreal
(iii) Terrestrial
4.
Give one reason why humans would hunt capuchin monkeys.
(1)
5.
The scientists recorded the alarm calls of capuchin monkeys on portable recorders.
Give one advantage of using portable recorders in the
wild.
(1)
6.
The scientists recorded alarm calls from capuchin monkeys who were over 3 years
old. Give one reason why they only recorded calls from monkeys over 3 years old.
(1)
7.
When a capuchin monkey sees a snake on the ground it gives the ‘snake’ alarm call
and then jumps up into a tree. Give one reason why it behaves like this. (1)
8.
Table 1 shows the percentage of encounters with predators when capuchin monkeys
gave alarm calls: the predators were birds (falcons and owls), humans, snakes and
caimans. The two columns show whether just one monkey gave the alarm call or more
than one monkey gave the call.
Table 1 The percentage of encounters when white -faced capuchin monkeys gave alarm
calls after seeing four types of predators.
Predator type
No. of encounters
Birds
Humans
Snakes
Caimans
153
12
65
8
Encounters when
only 1 monkey
called (%)
61
67
15
0
Encounters when > 1
monkey called (%)
39
33
85
100
(i)
How many encounters with these four predators did the scientists record?
(1)
(ii) Which predator did the monkeys encounter most frequently?
(1)
(iii) For the encounters with humans, how much greater was the percentage of
encounters when one monkey called than when more than one monkey called?
(1)
9.
Give two reasons why capuchin monkeys give sound signals (alarm calls) rather than
visual signals to warn of predators in forest habitats.
(2)
10.
Suggest one reason why you think it was always groups of monkeys that gave alarm
calls when they encountered caimans.
(1)
Total marks = 13
(This exercise was produced by the Association for the Study of Animal Behaviour
(ASAB). We are grateful to Elsevier for permission to use material from the article by
Fichtel et al. in Animal Behaviour, 2005, 70, 165–176.)
http://asab.nottingham.ac.uk/