|What could be cuter than a pygmy marmoset?|
|Three pygmy marmosets!|
|Pygmy marmosets in the Birmingham Zoo. Marmosets are polyandrous, living in family groups consisting of one female and two or three males. This sort of social structure is rare among primates (and among mammals in general). It seems like a good idea to me! ;-)|
Of course, they're not doing this just for fun. Marmosets tend towards the strategy of having many offspring, investing (relatively) less parental effort towards the survival of individual offspring. Births are usually twins, and a female marmoset can produce up to three pairs of twins per year. (In contrast, a female orangutan can give birth to a single offspring only once every 6 to 8 years.)
This high birth rate means that a tiny female marmoset could be pregnant, nursing twins, and caring for a pair of weaned offspring who are not yet independent, all at the same time!
The solution to this problem is to put the males to work. They do all the baby-carrying, and much of the general parenting as well. (The marmosets with the incredibly cute clinging babies pictured at left are therefore male.)
Since a female marmoset may have two pairs of babies needing carrying at the same time, she needs an extra male or two. The males don't know who is the father of a particular pair, so they look after them all equally. Very efficient!
|If only I had a pygmy marmoset willing to ride on my shoulder....|