How females tend to put in more investment and more choosy. Based on this, parental behaviour will correspond. for mates. Males less investment but take on mating effort, more energy into mating with lots of females. Whereas females take on parental effort, energy in making sure their offspring survive. This strategy only works if one parent is enough to sufficiently let the offspring survive. Can see biparental care in some species if need more parental investment in certain env"t. Dev"l maturity in which the offspring is born determines how much care is needed. Altricial: little care. b/c not very dev"l when born, need lots of postnatal care. Precocial: don"t need much care when born. They need lots of prenatal and postnatal but not as much as other species sine they can actually take care of themselves. Young tend to cling to mom; grasp reflex . Are altricial and need lots of care.