"Oophaga pumilio" is an external breeder, and other species of the genus "Oophaga" are notable in the amphibian world for exhibiting a high degree of parental care. The strawberry poison frog has dual parental care. The males defend and water the nests, and the females feed the oophagous tadpoles their unfertilized eggs. Although both male and female contribute to parental care, females invest more heavily in terms of energy expenditure, time investment, and loss of potential reproduction. When choosing a partner for mating, females will choose the closest calling male rather than the highest quality male. Females provide energetically costly eggs to the tadpoles for 6–8 weeks (until metamorphosis), remain sexually inactive during tadpole rearing, and care for only one clutch of four to six tadpoles at a time. The males contribute via the relatively "cheap" (in terms of energy) act of watering and protecting the eggs for a relatively short period (10–12 days), and can care for multiple nests at one time. The extreme maternal investment in their offspring is believed to be the result of high egg mortality. Only 5–12% of the clutch develops into tadpoles, so the female's fitness may be best increased by making sure those few eggs that form tadpoles survive.