as the confident knowledge that they will help us."
-Epicurus, Greek philosopher (341 - 270 BC)
Not the saying but the never needing to say is what counts.”
-Margaret Lee Runbeck, American author (1905 - 1956)
photo by Jérôme Micheletta, Macaca Nigra Project |
Where would we be without our friends? Friends lend a hand in bad times and cheer us on in good times. They make us laugh, share their food, and tell us where to find interesting things… like fruit or coconuts!
Okay,
so maybe finding fruit and coconuts isn’t that high on your priority list, but
it seems to be pretty high on the list for crested macaques. And lucky for
them, they have friends to rely on too.
Jérôme Micheletta and Bridget Waller at the University of Portsmouth in the United Kingdom set out to determine whether social factors influence the ability of crested
macaques to follow the eye gaze of a group-mate and potentially gain important
information. To do this, they hung out at the Marwell Wildlife Zoological Park
in Winchester, U.K. every day to watch and video record the crested macaques.
An experimenter would wait for two crested macaques to be within 1 meter of
each other with one individual facing the experimenter (they called this animal
“the informant”… not to be confused with Matt Damon) and the other individual
facing the informant and facing away from the experimenter (they called this
animal “the subject”). You can imagine, this process involved a lot of waiting
around. Once the animals were in place, the experimenter held up a yummy treat
(an orange, a banana, or a coconut). The informant would see the treat and then
the subject would either look at the treat or not. In these cases, the subjects
looked at the treats 64% of the time.
This figure from Micheletta and Waller's Animal Behaviour paper shows their experimental procedures. |
So it looks like crested macaques use their peers’ eye gaze as information on
where to look. They also were faster to look if their cage-mate moved his/her
head in combination with an eye movement, rather than just the eyes. But, does
the social context matter? For each pair of macaques, Micheletta and Waller
calculated the relative dominance status and friendship strength. They used
months of observations of aggressive encounters in which they knew the winners
and losers of each encounter to rank the overall dominance hierarchy of each
animal in the group. A typical aggressive encounter either involved one monkey
chasing another (which would either run away or crouch) or a monkey approaching
another and taking away his/her food or grooming-buddy or mate (How rude!). They
also determined friendship strength by calculating the average number of times
they sat in contact with or groomed a specific individual versus other animals
in the group.
If the informant was a friend, the subject was quicker to look at the food than if
the informant was not a friend, although friendship did not influence the
overall success rate. And the relative dominance status didn’t seem to have any
effect.
Why might macaques follow their friends’ gazes faster than nonfriends’ gazes? Maybe
they are generally more visually attentive to their friends than their
nonfriends, as is true in chimpanzees, siamangs, chacma baboons and ring-tailed
lemurs. Or maybe a friend’s information
is more relevant than a nonfriend’s information. Friends often share motivations
and needs and often compete less and share more with each other than with
nonfriends (although there are many exceptions to this, as you may have
experienced). All of these possibilities leave open new avenues for future
research. But one thing is clear: It sure is good to have friends.
Want to know more? Check this out:
Micheletta, J., & Waller, B. (2012). Friendship affects gaze following in a tolerant species of macaque, Macaca nigra Animal Behaviour, 83 (2), 459-467 DOI: 10.1016/j.anbehav.2011.11.018
Do you have a thought on friends that you would like to share? Comment below.
Cool, although an anti-climax given the title of the article
ReplyDeleteWhat did you think I meant by "benefits"?
DeleteThat's cool. I was expecting that maybe with a dominant informant, the subject would not look. But the idea about friendship leading to a faster reacting is really interesting.
ReplyDeleteI was surprised too with the results of the dominance analysis, but even in less tolerant species, individuals tend to pay more attention to dominant individuals, probably because they need to know what they are doing, maybe to be able to avoid conflicts.
DeleteI was also surprised by the lack of effect of dominance status on whether the subject looked and how long it took to look. It could be a reflection of the tolerance of the species. But now I wonder if dominance affects whether the subjects act on the information (e.g. approach the food item). Maybe to a tolerant and dominant crested macaque, a subordinate being aware of a food item is not as much of a problem as a subordinate approaching or consuming the food item.
Deletethat would be for another study :)
Delete