Why do many animal species provide parental care for eggs and young?

Many animal species provide parental care primarily to increase the survival, condition, and future reproductive success of their offspring. While parental care is a significant investment that carries substantial costs—such as reduced opportunities for the parent to seek additional mates or diminished post-breeding survival—it is an evolutionary strategy that enhances the likelihood that a parent's genes will be passed to the next generation.12

The decision to provide care is governed by a balance of costs and benefits. Because this investment is expensive, it is often the subject of conflict between the sexes, with the parent that can most effectively abandon the offspring without causing total reproductive failure often doing so. In many species, females provide the majority of care due to physiological constraints, such as internal gestation and lactation in mammals, or because they are more likely to be in proximity to the offspring when care is required.12

In some cases, care is provided by individuals other than the parents, a phenomenon known as group care. This is particularly prevalent in social insects, where sterile workers may maximize their own genetic fitness by caring for siblings rather than producing their own offspring.3