10.9 Wrapping Up:

Revisiting the seahorses, we can better understand how their unique trait of male pregnancy comes about. It is no surprise that unique traits arise in extreme environments, such as the vast and often unforgiving ocean. Seahorses have very high offspring mortality rates – only 1% of offspring born from a male’s brood pouch survive to adulthood. Most juveniles are eaten by fish and crustaceans. This is likely why seahorses have so many offspring at once – with more offspring, there is a greater chance that at least some will survive. In addition, high offspring mortality likely promoted polyandry within seahorses. Females invest their energy into egg formation and depositing eggs into as many males’ brood pouches as they can. Males invest in care of the developing embryos so that as many eggs as possible can successfully develop. This investment can compensate for extremely high offspring mortality rates. While most offspring will not survive, evolution ensures that the genes of those who do will continue on to future generations, allowing us to share the world with these magnificent creatures.

Watch a male seahorse give birth to over 1,000 offspring: