Experts uncertain if drone image captures newborn white shark

The internet was buzzing with "Baby shark, doo doo doo" news in late January.

A purported video of a recently born white shark, captured by a drone off the California coast, proliferated rapidly. The video drew in more than a million views and an array of news coverage. Environmental Biology of Fishes published a description by Carlos Gauna and Phillip Sternes on January 29th stating the shark was about 1.5 meters long and seemed to be shedding a white-ish layer, potentially due to recent birth.

Provided the sighting gets confirmed, this would represent the premier sighting of an exceptionally young white shark (Carcharodon carcharias), coming potentially mere hours post-birth. Additionally, this could help ascertain the breeding locations for these endangered and elusive sharks.

Carlos Gauna, an autonomous wildlife videographer, found the unique-looking young white shark in July near the Santa Barbara coast with Sternes, who is a marine biology researcher at the University of California, Riverside. While adult white sharks have a grey-ish topside and a white-ish underside, this shark seemed completely white. Size estimations and other hints regarding its age surfaced upon a video review, according to Gauna. There appeared to be shedding of a mucus layer and the fins looked underdeveloped.

Despite the intriguing nature of the observations, shark specialists warn against quick judgments. Chris Lowe, an ichthyologist at California State University, Long Beach, deems the case "interesting," but points out that the only supporting evidence thus far is a drone-captured video. Further confirmatory evidence such as other comparable sightings or testable samples would be required to confirm the hypothesis of the young shark being a newborn.

The investigators used words such as "possible" when discussing their findings and provided a potential alternate explanation for the milky layer—it could be related to a skin disorder. They also agree that additional sightings are necessary.

Regardless of whether the photographs depict a newborn, their sighting has renewed interest around these elusive creatures (SN: 6/30/14). We'll discuss what we know about white sharks and what the new findings can (and cannot) tell us.

The drone captured an aerial video 400 meters off the California coast, close to one of the four southern California coastal sites where young white sharks are known to aggregate, based on historical fishing records and increasingly advanced monitoring.

Michelle Jewell, a marine biology researcher at the Michigan State University Museum in East Lansing, recalls using helium balloons with attached cameras to monitor these sharks. Nowadays, drones, tagging, and satellite tracking are more commonly used tools.

Lowe and his team use drones to locate white sharks and then insert tracking tags by boat. Satellite data show a regular visitation pattern by young and juvenile sharks at these coastal sites, sometimes transitioning between these sites and staying for extended periods. Additionally, juveniles tagged by Lowe's team have been found in a fifth site in Baja, Mexico. "In a year, they have migrated down to Mexico, and back to California," reports Lowe.

Unlike many animals, baby great whites receive no parental care (SN: 02/09/2023). The young sharks are left to fend for themselves, using these coastal sites as safe nurseries that offer protection from larger predators and accessible food sources.

The mystery remains.

“Personally, I think that these young ones are born nearby,” says Gauna. Far offshore births would require newborns to navigate treacherous, predator-filled waters to reach the safer coastal nurseries, he and Sternes suggest.

Contrary to this view, certain experts argue that available evidence does not support coastal births. These experts propose seeing a singleton would be unusual if a female had recently given birth nearby—white sharks typically have 10 pups at a time, carried in two uteruses running the length of their body. The litter measures a total of about 15 meters long.

“California is the most heavily flown-over coastline in the world,” Lowe mentions. “Between helicopters and fixed-wing planes, if 18-foot big females were coming in and dropping pups along our beaches, somebody would see it.”

Satellite tracking data (SN: 01/04/2019) have also shown that “around every three years, large female white sharks go far from their regular home range, stay there for a while and leave,” Jewell says. That suggests that the reproductive cycle for female great white is three years. But the tracking data alone do not have enough information to say what white sharks do in these far-flung remote places.

That’s a mystery too — because no one has witnessed a white shark giving birth.

But there is a way to visually estimate a young shark’s approximate age: Look at the color and texture of the yolk scar present between its pectoral fins. “It is like a belly button, where the baby shark used to have its yolk sac,” Lowe says. The yolk sac, which nourishes the embryo, gets used up inside the mother’s uterus, leaving a mark where it was once attached to the pup. The scar appears red and raw-looking in the smallest white sharks Lowe’s team has caught. As the white shark grows, the scar turns white and becomes raised, disappearing by about the time the shark is a year and a half old.

Gauna and Sternes couldn’t spot the underbelly yolk scar from a drone shot. But they say there is another visual clue to the shark’s age: Both the dorsal fin and pectoral fins of this shark seemed underdeveloped and rounded.

“Why would the fins be rounded?” Gauna asks. “Well, to exit the [womb of the] mother.” That rounded shape has been documented in embryonic sharks found inside pregnant females that have died.  By the time the sharks are a year old, the fins take on a sharper, more defined shape, Sternes says.

But with a drone shot alone, it is hard to gauge the depth of the shark’s location, making it difficult to estimate its true shape and size because water can distort an image, Lowe says.

Another clue to the shark’s age is the white material that seemed to be sloughing off its body in the video, Gauna and Sternes say. It could be a film of substances from the womb that coated the pup during birth and still clung to it. An autopsy of a pregnant shark in 2016 revealed that her uteri contained a lot of “yellowish viscous uterine fluid.” While it’s unknown how long the sharks produce this “uterine milk,” that’s what could be covering the young shark, the researchers suggest.

An unknown skin condition is another possible explanation, the team and other experts say. When sharks visit coastal sites, “they are in areas that have a lot of pollution and human runoff,” Jewell says, which could cause a skin infection (SN: 08/01/2012).

While experts agree that the team have spotted something unusual, they say it is too early to jump to conclusions on whether it is a newborn.“We need to add a layer of science and go and repeat and try [to] see the same thing over again and collect samples to whatever it is that’s coming off of that shark,” Jewell says. “What that something is, will then help us answer the rest of it.”