A recent study published in Animal Behavior has shown that among female vervet and sooty mangabey monkeys, grooming is traded in exchange for getting to play with baby monkeys. Female monkeys are eager to cuddle with baby monkeys, even those that are not their own offspring. However, the mothers of the babies often demand grooming from the interested female before allowing play time.
Incredibly, these exchanges have been shown to be a ‘market’ and follow market forces. The price, or grooming time for the mom, varies depending on how many babies are around, or the supply. When the first babies are born, the mothers can demand longer grooming sessions from interested females than later on in the season when there are more infants around. In other words, when the supply is low at the beginning of the season, the price is higher than at the end of the season, when the supply is higher.
The age of the baby also determines the price the mom can demand in exchange for playtime. The younger the monkey, the longer the mom was groomed. Friendships and associations also impacted the accessibility to the babies. Monkeys that were familiar and liked by the mom would get to hold the babies in exchange for less grooming than would be demanded from a lesser-known female. Finally, another factor is a female’s ranking within the group. High-ranking females who want to handle a baby did not have to invest as much time grooming as would a lower ranked female interacting with the same mom.
I find it incredible that monkeys in these interactions can interpret the ‘market’ in order to get what they want. If a lower ranked female wants to play with an infant, she has to be able to decipher the correct grooming time needed to satisfy the mother. But the correct time would be different depending on if the female knows the mother or if she is higher or lower ranking than the mother. I knew that monkeys had complex social structures and interactions but I find it fascinating that we can apply something so human as market forces to monkeys playing with cute babies.
-Posted by Muriel Herd
Its interesting to know that other animals also give ultimatums. Grooming in exchange for play is a good example of this. Play is a relatively new discovery in the animal kingdom and this is an interesting example of it. Why do you think that the younger monkeys had to groom longer?
ReplyDeleteAlberto Suarez
This is very interesting - and certainly seems like a very clever move. Has this been observed in any other monkeys? How do the mothers "demand" grooming? Was any conflict observed between females who maybe had different ideas of what the appropriate amount of grooming or play time was?
ReplyDelete- Dana Mirsky
Perhaps I should clarify, when I said "The younger the monkey, the longer the mom was groomed" I meant that the younger the baby monkey was, the more grooming the mother demanded. So for an infant/newborn, the mom was groomed longer than if someone wanted to play with it when the baby was 3 months old.
ReplyDeleteThe study was done only on those two species of monkeys, although they reference another study done on moor macaques. From what I can tell from the study, the mother monkeys simply do not let other females touch their babies without some grooming in return. There was no mention of any hostile interactions or fights over the babies, although it was said that all monkeys treat all the babies with care but I'm not sure if the same is true for adult interactions.
-Muriel Herd