Life cycle Sperm whale

sperm whales can live 70 years or more. prime example of species has been k-selected, meaning reproductive strategy associated stable environmental conditions , comprises low birth rate, significant parental aid offspring, slow maturation, , high longevity.

how choose mates has not been definitively determined. males fight each other on females, , males mate multiple females, making them polygynous, not dominate group harem. males not provide paternal care offspring.

females become fertile @ around 9 years of age. oldest pregnant female ever recorded 41 years old. gestation requires 14 16 months, producing single calf. sexually mature females give birth once every 4 20 years (pregnancy rates higher during whaling era). birth social event, mother , calf need others protect them predators. other adults may jostle , bite newborn in first hours.

lactation proceeds 19 42 months, calves, rarely, may suckle 13 years. other whales, sperm whale s milk has higher fat content of terrestrial mammals: 36%, compared 4% in cow milk. gives consistency similar cottage cheese, prevents dissolving in water before calf can eat it. has energy content of 3,840 kcal/kg, compared 640 kcal/kg in cow milk. calves may allowed suckle females other mothers.

males become sexually mature @ 18 years. upon reaching sexual maturity, males move higher latitudes, water colder , feeding more productive. females remain @ lower latitudes. males reach full size @ age 50.