Monkeys play to reduce group tension
Play amongst adult howler monkeys increases during competitive foraging
Date:
March 17, 2022
Source:
Anglia Ruskin University
Summary:
New research has discovered that monkeys use play to avoid conflict
and reduce group tension. The study found that adult howler
monkeys spend more time playing with other adults, rather than
juveniles. And rather than being associated with fun or education,
play increases when howler monkeys are foraging for fruit, which
is a highly prized resource that generates competition.
FULL STORY ==========================================================================
New research has discovered that adult howler monkeys use play to avoid conflict and reduce group tension, with levels of play increasing when
they are faced with scarce resources.
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The study, carried out by a team of researchers from Spain, Brazil and the
UK, and published in the journal Animal Behaviour, focuses on the activity
of two subspecies of howler monkey: the Mexican howler (Alouatta palliata mexicana) and the golden-mantled howler (Alouatta palliata palliata).
The researchers examined how play varies with age, and they measured the
amount of time adults play with other adults and with juvenile monkeys
within their groups.
Howler monkey play involves individuals hanging from their tails
and making facial expressions and signals, such as shaking their
heads. However, play is an energy-costly activity for howler monkeys, who generally have an inactive lifestyle due to their mainly leaf-based diet.
By studying seven different groups of howler monkeys in the rainforests
of Mexico and Costa Rica, the researchers found that the amount of adult
play is linked to the number of potential playmates, increasing in line
with the size of the group. Adults spend more time playing with other
adults, rather than juveniles, and adult females spend more time engaged
in play than adult males.
Crucially, the researchers found that play amongst adults increases in
line with time spent foraging on fruit. Howler monkeys typically eat
leaves, and fruit is a highly prized resource that generates competition amongst the monkeys.
Howler monkeys do not have a fixed social hierarchy within their groups to navigate competition and conflict, and they do not engage in collective grooming, which is used by some primates for group cohesiveness and
tension reduction. Instead, the study authors believe play has a key
role in helping howler monkeys regulate relationships within their social
group and avoid conflict.
Co-author Dr Jacob Dunn, Associate Professor in Evolutionary Biology at
Anglia Ruskin University (ARU), said: "Despite its appearance and our
own perception of what play means, play is not always associated with
frivolity or education.
Instead, we think it fulfils an important function in howler monkey
society by reducing tension when there is competition over scarce
resources.
"We found that levels of play are at their highest when howler monkeys
are feeding on fruit -- which is a valuable and defendable resource --
and female adults play more than males. This is striking, as females would
be more vulnerable to food competition than males. Howler monkeys are
a particularly energy-conservative species, and we would have assumed
females would have played less, as they are also constrained by the
energy requirements of reproduction." Lead author Dr Norberto Asensio,
of University of the Basque Country, said: "One theory for the positive
effect of fruit consumption on play is that a fruit-based diet simply
provides the howler monkeys with more energy compared to their typical
diet of leaves.
"However, if this was the case, we should have observed adults engaging
in more play with all members of the group during fruit foraging, rather
than just with other adults. Because juveniles do not pose a threat or
provide competition at fruit trees, we believe that play amongst adults
is a mechanism for solving conflicts within the group, in a similar way
that grooming is used by some other primate species."
========================================================================== Story Source: Materials provided by Anglia_Ruskin_University. Note:
Content may be edited for style and length.
========================================================================== Journal Reference:
1. Norberto Asensio, Eugenia Zandona`, Jacob C. Dunn, Jurgi Cristo'bal-
Azkarate. Socioecological correlates of social play in adult
mantled howler monkeys. Animal Behaviour, 2022; DOI: 10.1016/
j.anbehav.2022.01.017 ==========================================================================
Link to news story:
https://www.sciencedaily.com/releases/2022/03/220317094737.htm
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