New seahorse study redefines the term ‘superdad’

Scientists from Australia, the United States and Switzerland recently got together to shine a light on the more intimate details of seahorse pregnancy, and their amazing findings might just redefine the term ‘superdad’.

‘In a nutshell we found seahorse dads’ brood pouch, that holds the females’ deposited eggs, undergo changes and processes quite like human mums,’ says Camilla Whittington of the University of Sydney, co-author of the recent study.

Whittington and her colleagues looked at Australia’s pot-bellied seahorse, monitoring their gene expression over the full course of the little swimmer’s 24-day pregnancy. Little is known about the brood pouch of male seahorses but, before this study, they were generally considered to be little more than a simple storage container for developing young.

Whittington says their work is evidence the dads are doing much, much more. In their study, males’ pouches acted a bit like umbilical cords, offering seahorse fetuses nutrition, immune protection, and even removing harmful waste-related toxins. The fathers absorbed their babies’ waste and then excreted it themselves.

‘Males provide fats for energy and minerals like calcium, crucial for the newborn’s skeletons and body plates,’ says Whittington. ‘They have antibacterial and antifungal action, and make something that looks like immune compounds, all important considering the pouch is fairly unsterile at the start, open to seawater that’s full of microbes.’

Photo by Rudie Kuiter / Aquatic Photographics

While these were all amazing, and one-of-a-kind finds, an even more impressive discovery was that these processes were using the same genetic codes as many other pregnant-animals. This leads to even more complicated questions going beyond just seahorses, about why all pregnancy-undergoing wildlife seem to use the same codes.

This is a great case of convergent evolution, Whittington says, where many animals have developed similar traits in isolation of one another. Sometimes this occurs for totally different and incidental reasons, but pregnancy seems to be an example of many unrelated species solving the same problem the same way.

Whittington normally works with platypus-venom genetics, but says she hopes she’ll get to pursue this unique evolutionary question further.

‘Seahorses are a great model, given their role reversed sexual traits—females compete for males, and they’re the only species alongside pipefish where males take on pregnancy,’ says Whittington. ‘We figured out part one, now we’re out to learn how these traits arose.’