Shark Week 2018: Great White Shark Nursery Is Terrifying, but Kinda Cute
Great white sharks are incredibly elusive, but scientists are using modern technology and some old-fashioned elbow grease to unlock their secrets. In Great White Shark Babies, which airs Friday night on Discovery Channel’s Shark Week, scientists explain how they discovered one of the world’s very few known great white shark nurseries and are beginning to build a great white shark family tree.
Despite their size and long life, we know remarkably little about great white sharks, “even very basic facts like where they mate, where the females go to give birth, and where the pups live before they swim out and rejoin the adults in the open ocean,” Toby Daly-Engel, an evolutionary biologist at Florida Institute of Technology, tells Inverse. Fortunately, she and her team know where to look, and when they did, they found more than they bargained for: a surprising family connection.
In an isolated bay off of Baja, California, she and her colleagues Mauricio Hoyos Padilla and Michelle Wcisel started their search. When they came across a grey whale carcass with small bites out of it, they knew they were looking in the right place. And their suspicions were soon confirmed. By enlisting the help of local fishermen who used a specially constructed longline fishing rig, they successfully caught baby sharks and took tissue samples from over the side of the boat. Confirming the presence of baby great white sharks was extremely exciting for Hoyos Padilla, who exclaimed that, in a career of studying great white sharks, he had never seen a baby.
They weren’t finished there, though. In addition to finding the nursery, they also wanted to track down where the pregnant females that birthed their babies were coming from. After all, the mothers, perhaps eager to be rid of their burdens after gestating for two years, don’t stick around after giving birth. For this reason, it’s difficult to connect parents to offspring.
To fill out the picture, the researchers then went to nearby Guadalupe Island, where adult sharks are known to hang out, and took some much riskier samples. Using a punch biopsy tool attached to the end of a spear, Daly-Engel and her colleagues collected tissue samples from eight adult sharks and brought them back to the lab. They also attached radio antennae to three pregnant females. Check it out:
“I was so enamored, and so in awe of them,” says Daly-Engel of her moments underwater with the great whites. “They’re so amazing in person, and they’re so beautiful and majestic that part of me just kind of wanted to sit there and stare at them with my jaw on the ground because there’s that sense that you’re face-to-face with this icon. I’ve never been that close to a great white shark before. The part of me that really loves to watch Shark Week was kind of freaking out, but the rest of me knew it was time to work.” And despite being starstruck, she got the samples.
Their goal, with the DNA samples and the antennae, is to draw a clear connection between the adult sharks in one place and the baby sharks in another. The DNA samples should eventually help scientists build a family tree of adult and baby sharks, and the radio tags may eventually help show the sharks’ migration patterns. This will help scientists begin to piece together the life cycle of the great white shark, which Daly-Engel reminds us we know surprisingly little about, due in large part to their elusive and unpredictable nature. They’re a lot different than, say, whales, whose migration routes we know with great certainty.
“Oftentimes whales, you will see them around kind of the same place year after year, so we start to understand about that part of their life cycle, but with great white sharks, you don’t see them very often,” she says. “They’re down deep, they’re not coming up to the surface to breathe, they’re very careful and kind of shy, and so even when they’re there, people may not be aware of it. It makes them hard to study. Also, they’re kind of dangerous.”
With her team’s findings, Daly-Engel hopes to add a couple small pieces to the great white shark puzzle, but they didn’t expect to get a clear picture. And this is where they got the biggest surprise:
Based on the results of the DNA samples, they found that two pairs of baby sharks, born two years apart from each other, turned out to be from the same mating pair of adults. This, says Daly-Engel, is mind-blowing.
“It was so surprising and so different. We didn’t expect to find any relatedness among these sharks because, you know, it’s a big ocean,” she says. “It would be like picking two people out of a crowd, days apart from one another, and yet finding out that they’re brother and sister.”
It’s an astounding find, but perhaps more significantly, Daly-Engel points out that it shows just how small the population of great white sharks may be. After all, they don’t form long-term mate pairs, so if the same pair of sharks hooked up twice, that suggests that these animals simply aren’t that numerous. By bringing this picture into focus, scientists can start to get a handle on the issues facing great white shark populations.
“We knew that great white sharks are one of those species that needs protecting, and the habitat that the babies live until they join the adults is critical habitat,” Daly-Engel says. “By identifying that habitat and starting to really understand not just how and when the animals are using that environment but also to start to get a sense of how many there are gives us a sense of how healthy that population is. Given that we were able to detect these related individuals just through random sampling, to me, suggests it’s a small population to begin with, which makes it even more important that we be able to protect them.” Daly-Engel hopes to publish this research by the end of 2018.
Great White Shark Babies airs Friday, July 27 at 10 p.m. Eastern on Discovery Channel.