We tend to think of sharks and rays as being egg-layers (chances are you've seen one of their otherworldy mermaid's purses), but as beachgoers in Namibia found out last week, many species actually give birth to live young.
Kolette Grobler, a marine biologist at the Ministry of Fisheries and Marine Resources in Namibia, had planned for a normal day in the lab when a call from concerned animal rescue officials sent her rushing to the beach. A bluntnose guitarfish* (Acroteriobatus blochii) had not only stranded, but it had also begun giving birth to a brood of tiny babies.
"The first call-out came halfway through my first kick-start cup of coffee of the morning," she wrote on Facebook. "With the intriguing question, 'Do sandsharks give birth in the water or on land?'"
Contrary to what their common name might tell us, the pointy-nosed ocean dwellers aren't sharks at all – they're rays. And they certainly don't make a habit of basking on sandy beaches. The likely explanation is that this fish was chased inland by a predator.
"The local SPCA [who found the ray], mentioned there was a big seal in the waters close by, shortly before they found her," Grobler said. "She had already given birth to about five babies by the time I arrived, but more were still coming out, each with its yolk sac still attached."
The presence of the large yolk sacs indicates that these babies were born prematurely. Because the embryos feed off the nutrient-rich yolk, we would expect a fully developed baby ray to emerge with little (or none) of it remaining.
Despite their fearsome reputations, many elasmobranchs (sharks, skates and rays) are sensitive to stress, and as such have been known to go into early "labour" after long battles (either on the line or with would-be predators like our lurking seal).
Grobler feared the worst when the pups began floating upside down, initially showing no signs of life. After several attempts by the team to right the young, one by one, they began to swim.
"Seven babies were alive and swimming around quite strongly, although slightly lopsided due to the drag effect of the yolk sac," she told us. "Because we were worried about them being seen from the air by predators like kelp gulls, we took them into deeper, darker water."
Grobler gently nudged the pups towards their mother, who was lying quietly on the seabed – an eighth pup still on its way out. "We did not want to pull it out in case we'd cause damage to either baby or mother," she said. "I checked her spiracles one last time, and saw them closing and opening, so I knew she was still alive."
Exciting as this rescue is, it's important to note that these babies are certainly not out of the woods. Even in a healthy, fully developed brood, only a fraction of pups will actually make it to adulthood. Experts pegged these newborns at two to three weeks premature, which means they were likely developed enough to function on their own – but whether or not they made it remains a mystery.
On that note, should you find yourself in a similar situation, the best course of action is always to contact your local wildlife officials. Handling stranded marine life, even with the best intentions, can sometimes do more harm than good.
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