Prehistoric Great White Shark Nursery Discovered in Chile

A great white shark nursery dating back around five million years has been discovered in Chile. The paleo-nursery potentially provides an insight into the evolutionary success of the predator, as well as ways for conservationists to help preserve the species, which some scientists believe may be at risk of extinction.

In a study published in the journal Scientific Reports, an international team of researchers say this is the first paleo-shark nursery to be discovered. It was found during an assessment of great white shark teeth at three locations across South America. These all date to the Pliocene Epoch, between roughly five and 2.5 million years ago. They had not been specifically looking for a great white shark nursery, but noticed one site appeared to have a large proportion of teeth from young sharks.

Great white sharks breed by an egg growing and hatching inside the mother, with the pup then being born in nurseries where they are protected from predators until they are large enough to safely leave. The locations of these breeding areas are not well known and scientists are currently trying to find them in an effort to protect the species. For example, OCEARCH, a non-profit that tracks marine species, has recently spotted a mature female heading out into deeper ocean, on a trajectory associated with other potentially gestating great whites. By following the shark's movements, they hope to understand where it gives birth.

The prehistoric shark nursery identified in the latest study was found in the Coquimbo locality. The team had been collecting material to better understand sharks and rays from the region. "We were quite surprised to find such high numbers of juvenile white shark teeth in the area," study author, Jürgen Kriwet, Chair of Palaeobiology and Vertebrate Palaeontology at the University of Vienna, Austria, told Newsweek in an email.

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Teeth from the Coquimbo site were found to mostly be from young sharks, with some adolescents and no adults. At the other two sites, body sizes varied considerably. This led the team to conclude they had found a pliocene great white shark nursery.

Exactly how long the breeding was used for is not known. Rough ages put it between 5.3 and 26 million years old. Kriwet said it may have been used for just a few dozen years, but it could have been hundreds of thousands, or even millions, of years.

Because great white sharks grow slowly and produce few offspring, coupled with anthropogenic pressures, they are believed to be an at-risk species. Talking about the locations of modern great white shark nurseries, Kriwet said finding them and carrying out long-term monitoring and analysis is challenging. "Recently, there was one discovered in the northern Atlantic off New York," he said. "More might be around, but then again, we first have to discover them and a lot of time, effort and also money is necessary for this. And what is also probably a problem: these areas might shift their locations due to climate change."

If these nurseries can be found, they can be protected, so identifying their locations is of the "utmost importance," Kriwet said. "Moreover, [if] we can reconstruct shifts due to climate change (as we propose for the past) we can better understand the impact of ocean warming on these important top predators in food-webs and thus also how food-webs might be altered in the future due to climate change."

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Douglas McCauley, Associate Professor of Ecology, Evolution, and Marine Biology at the University of California Santa Barbara, who was not involved in the study, told Newsweek that habitat loss and degradation has led to the loss of many shark nurseries. And despite being one of the most famous creatures on the planet, little is known about great white nurseries. "Part of this is because we have driven adult white shark populations down so low in many areas that there simply haven't been enough offspring to be able to detect a nursery," he said.

"One thing that is interesting is that this study suggests white sharks may have been a lot more common in the past off the Pacific coast of South America than they are today. The fossil record sheds they report on appear to paint a picture of Peru and Chile a million years ago that hosted thriving nurseries full of baby white sharks and buffet zones teeming with adults. But today white sharks are fairly rare in that region."

McCauley said the authors suggest there may have been more white sharks and nurseries off the coasts of Peru and Chile because the waters there were warmer at this time. "This opens up the possibility that if climate change slowly but surely warms historically cold water areas, we might eventually see white shark nurseries popping up in new places," he said. "That matters. It is a privilege to share the waves with a creature that has been out there being big and beautiful for millions of years, but as is the case with most wildlife—it takes care to make sure we share that space safely."

This article has been updated to include comments from Douglas McCauley.

great white shark
Stock photo of a great white shark. Researchers have found a great white nursery dating back between five and two million years. iStock
Prehistoric Great White Shark Nursery Discovered in Chile | Tech & Science