Sea monkeys are actually brine shrimp, and like most animals, they require sexual reproduction. This means they need both a male and a female to produce offspring.
While some species of brine shrimp can reproduce through a process called parthenogenesis, where females can produce offspring without fertilization, this is not the case with the species commonly sold as "sea monkeys".
So, while it might seem like your sea monkeys are multiplying rapidly, they are actually getting their start from the eggs that came with the kit. These eggs contain both male and female brine shrimp, allowing them to reproduce through traditional sexual means.