Social Relationships between Males and
Constraints on Male-Female Relations
- One is the ratio of
males to females- the social organization of their species will affect
the types of relationships that males and female scan have.
- Another is the biology of the species- in some, the males are
stronger, larger, and have better weapons.
Let's look at the
different types of social system which can affect male-female
- Monogamous system, like in
- There is little opportunity to form relationship besides
the one with the mate, so there's not much complexity in choosing who to
mate with and who to hang out with. People have done preference
experiments in the lab and it has been shown that monogamous animals even
when given a choice, choose their usual partner to associate with.
- Polygynous system, like in the gorilla.
females are not related to each other and so have little to offer each
other socially. The male protects the females from outside males.
Long-term bond form between the dominant male and the female sin his
group- if he disappears, the females all disperse.The females are
submissive to the male, and take more of the responsibility for staying
near the male and maintaining proximity. The subordinate males do tend to
hang out with females more than other females, but these proximities are
the responsibility of the subordinate males, not of the females he's
hanging out with.
However, remember the differences between gelada and
hamadryas baboons; They both live in one-male groups with several
females, but because of dispersal differences, the relationships are
|Female-bonded; males disperse||Male-bonded; females
|If the male disappears, the group
will still stay together and probably find another male.||If the
male disappears, the group will disperse. He holds the group together by
aggression and herding.|
|The females are
power brokers and have a lot of influence in which males will join the
group.||There is a lot more competition and less cooperation among
the females. (Since they're not related.)|
- Multi-male, multi-female system, like the common
- The females are mostly solitary in the chimp, so they
haven't been studied as much, since males and females don't have too much
contact outside of estrous periods.
In bonobos, however, males and
females spend a lot of time together. Females maintain strong
relationships with their sons even after they're grown. Females are also
sexually receptive throughout their lives, even when lactating or
In Savannah baboons, male-female relationships have also
been studied. They're a female bonded group, and most grooming and
alliances occur within matrilines. There is extreme sexual dimorphism
(2:1 ratio) and the males have much huger teeth than the females. Studied
show that the higher ranking males do get most of the matings, but the
lower-ranking males get more than their share as well.
Female mate choice. Why would they prefer these low
ranking males? We must look beyond their estrous period and into the rest
of their lives; Baboons give birth every 5-8 years. After birth, they
lactate for about two years, with no cycling. They only go through about
5 cycles before they conceive again, and their gestation period is about
6 months. So, they spend about 10% of their lives cycling, and that was
usually the only portion that people studied when they wanted to know
about mating behavior. Barb Smuts looked at the other 90% of their lives
and how that affected the mating behavior.
She found that females have certain guys that they spend
most of their time with. A female spends very little time with most of
the males but much time with one male. This was a surprising find in a
species we had always termed promiscuous. She termed these pairings
"friendships," and defined friendship in terms of
proximity and grooming. Females spend a
lot of time in close proximity with their friend, and almost no time with
other males. If grooming were randomly distributed throughout he groom,
then you would expect that any pair would be grooming each other about 6%
of the time, but friendship pairs mostly (or even exclusively!) groom
Most female shave one friend or maybe two. Besides proximity
and grooming, they often travel together, feed together, and solicit
grooming from each other. The female is relaxed around her friend.
Usually, when a male approaches, the female goes through ritualized
submission- she presents. However, when it's a friend who is approaching,
the females don't do this.
So, who is maintaining the relationship?
Robert Hinde can up with a system to quantify this. You watch any time a
female or a male in your target pair approaches or moves away from the
other. Then you subtract the percentage of the time that the female
leaves from the percentage of the time that the female approaches. This
gives you a continuum from -1 to 1. If your number is -1, then the male
is responsible for maintaining the relationship, while if you get 1, the
female is. At 0, they're both doing it. When they apply this to baboon
friendships, they find that in most cases it's the responsibility of the
females to maintain the friendship, but in some pairs, it's the male. If
they're both doing some of the work, then what are they each getting out
Benefits to Females
- The friends protect
females from aggression from other males- a female gets attacked about
once a week, and receives a serious wound about once a year. A male will
protect his friend from other males. In instances where a male went tot
he defense of a female, about 90% are friends of the female, and only
about 10% were other males.
- The friends also defend their
- Also beneficial for the female, her friend often
develops good relations with her infant. He will carry it around, groom
it, pick it up, and allow it access to good feeding sites. What's good
for the baby is good for mommy.
Benefits to Males
"Friendships in the past doubled the probability that a male
would form a consortship with that female in the future."
Also, beside increasing mating probability, there's another benefit which
may be important- the male often uses the baby of his friend to fend off
aggression from other males; when someone threatens him, he grabs the kid
because the other guy knows that if he hurt the baby he'd be mobbed by
the mom and her matriline.
So, the males increase their mating
chances, while females increase their survival and that of their infants-
so this is a case of reciprocal altruism.