We can see what love encompasses in studies of the fluffy little titi monkey conducted by Bill Mason and Sally Mendoza of the University of California. Females nurse their babies but don't offer any other maternal responses. They do not groom or touch their infants. The true nurturer is the male, who assumes 80 percent of the infant care. It's the male who holds and carries the baby, who is emotionally engaged and is the safe haven. Baby titis don't seem to mind at all when the mother is removed from the family for a while, but when the father is taken away, the infants' levels of the stress hormone cortisol soar.