grouping in polygynous structures.  Even though the adult male may 
display dominance over the females, the females form the stable part of 
the society, remaining in a nearly permanent association with their 
relatives.  The females also have the ability to accept or reject any new 
male, by acting as a "gate-keeper" for the male's sexual desires.
	The fourth type of sexual strategies displayed by primates is 
polyandry.  Among non-human primates polyandry is the dominant 
natural state only in some New World Monkeys, such as marmosets and 
tamarins. Polyandry, in these species, consists of one female and two adult 
males and any dependent young.  Both of these species, referred to 
collectively as the callitrichirdae family, are considered the most primitive 
of all monkeys, retaining claws, rather than nails, that ancestral primates 
are known to have had. The callitrichirds also give birth to twins, rather 
than a single child, as is the normal for all other primates.  Because of the 
presence of two males, the callitrichirds are the only known non-human 
primate species, other than some cases in orangutans, whose males take an 
active role in child rearing.
	The fifth, and final, type of sexual strategy displayed by primates 
is living a solitary life and coming together only for mating.  This is the 
"state of nature" exhibited by the vast majority of non-primate mammals.  
This type of solitary lifestyle is used only by nocturnal prosimians, such as 
aye-ayes, galagos, and lorises, the most primitive of all primates.  Since 
these primates forage for food at night, it is their best interest to keep their 
group number as small as possible, in order to reduce the threat of 
detection by predators.  There is, however, evidence that some of these 
prosimians live in groups of two females and their respective offspring, 
when their offspring are not yet mature. These animals display a retention 
of the primitive mammalian predilection to olfaction and the production of 
chemicals that can be detected by members of the opposite sex, to 
encourage mating.
	While it is important to know the sexual patterns of all primates for 
their own value, their use as models of the human "state of nature" is 
particularly important.  Much research has been done on humans and our 
ancestors that one can compare with results of similar research on non-

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