No horsing about: why this little guy’s top of the pops

STEALTHY daddy seahorses generally give birth under the cover of nightfall to reduce the chances of their newborns being eaten by beady-eyed predators. Knysna daddy seahorses (Hippocampus capensis) will give birth to between seven and 120 baby seahorses per brood.

How does a daddy seahorse come to give birth? Well, just to clear things up, seahorses aren’t hermaphrodites. In fact, it starts with a wannabe daddy seahorse. He will parade around, showing his empty pouch to prospective females.

An eager female will transfer her eggs into his pouch. There he will fertilise the eggs and they will embed into his pouch’s tissue lining. Here each egg will develop into a teenytiny seahorse with eyes that move independently like a chameleon, mouth like an anteater, pouch like a kangaroo and prehensile tail.

The temperature of the water around him influences how quickly they develop. Warmer water means they grow quicker; it can take between 14 and 45 days for Knysna seahorse babies to emerge.

Because daddy seahorses are pregnant, freeing up mommies to go their merry ways, and give birth to so many babies, we tend to think of them as some kind of super dad, but after their babies emerge from their pouch, some species have been known to eat their own offspring, making them satiated dads rather than super dads.

But to be fair, seahorse dads typically don’t eat for several hours after giving birth. After this fasting, the daddy seahorses’ fatherly commitments are complete and baby seahorses are left to fend for themselves in the big, wide sea, or in the case of Knysna seahorses, the big, wide estuary.

Knysna seahorses are the only seahorses that don’t live in the sea. They are only found in three estuaries on South Africa’s South Coast, one of which was in the news recently.

At 3.30am on May 25, a big excavator rumbled to life and gouged the last bit of sand separating the Swartvlei Estuary from the sea. Over the next few days, water levels in the estuary began to drop, leaving Knysna seahorses stranded, motionless on the banks, their prehensile tails wrapped tightly around aquatic plants.

Without water, these creatures would soon dehydrate and die. But Sanparks Seahorse Citizen Science Programmes volunteers sprang into action, returning stranded seahorses to the safety of deeper water. |

Button is a marine biologist, commercial diver and surfer, and has a Master of Science degree in Conservation Biology from UCT. This was first published by Roving Reporters.