Like most other hammerhead sharks, the smalleye hammerhead shark is viviparous, meaning that it gives live birth. They mate in August and September and females are pregnant for around 10 months before giving birth to 5-12 pups in May and June. Males and females mature when they are 80 to 98 cm (31 to 39 inches) long. But male smalleye hammerhead sharks found off the northern Brazilian state of Maranhão mature when they are 92 cm (36 cm) long, while females mature when they are over 101 cm (40 in) long.