The Secret Winter Lives of Great White Sharks

19 June 2026 | White Shark Ocean

Every autumn, the great white sharks of the western North Atlantic disappear. The sharks that spent their summer months hunting in the cool, prey-rich waters off Nova Scotia, Cape Cod and Long Island simply vanish — and for most of modern history, nobody knew where they went.

Now, thanks to the largest acoustic tagging study of great white sharks ever conducted, we do. And what researchers have found has rewritten our understanding of one of the ocean's most iconic animals.

92 Sharks, One Answer

The study, published in March 2026 by researchers at OCEARCH Wildlife Research, tracked 92 individual great white sharks over multiple years using a combination of acoustic telemetry, satellite tags and citizen science sightings. It is the most comprehensive longitudinal study of this kind ever completed for the species in the Atlantic.

The findings were clear: when water temperatures drop below roughly 14°C in late October and November, the sharks begin moving south and west in sustained migrations of up to 4,000 kilometres. Their destination, in the overwhelming majority of cases, is the Gulf of Mexico — specifically the warm, shallow waters along the West Florida Shelf and a submerged feature called Pulley Ridge, an ancient coral reef system sitting in about 70 metres of water approximately 250 kilometres west of the Dry Tortugas.

There, in an area so remote it sees almost no commercial fishing and even less recreational traffic, the sharks spend their winters.

What They Do There

The behaviour of sharks in their Gulf of Mexico winter grounds is markedly different from what researchers observe on the summer feeding grounds. Acoustic data shows the sharks spending significant time at depth — between 40 and 100 metres — with relatively low horizontal movement. Their activity patterns suggest reduced predatory behaviour and possible metabolic downregulation: in short, something approaching a slowed, energy-conserving state.

Researchers believe the Gulf serves as a thermal refuge — deep enough to stay cool, warm enough to avoid the metabolic stress of cold North Atlantic winters — as well as a possible social gathering area. Multiple sharks converge on the same relatively small areas simultaneously, which raises the intriguing possibility that the Gulf winter aggregations play a role in reproductive behaviour.

The First Birth Ever Filmed?

That possibility became considerably more interesting in February 2026, when a paper in Environmental Biology of Fishes by marine biologists Carlos Gauna and Phillip Sternes described footage captured off the California coast — not in the Gulf, but directly relevant to the question of great white reproduction. The footage, taken from a drone, appeared to show a very large female great white shark accompanied by a small, pale juvenile covered in what the researchers described as a white, oily film consistent with uterine fluid — the biological residue present on a newborn pup.

If confirmed, this would be the first footage ever captured of a great white shark being born in the wild. The species' pupping grounds have never been directly observed anywhere in the world, and the discovery sent a significant ripple through the marine biology community.

"We may have just witnessed the birth of a great white shark," said Gauna. "That would be a first for science."

The paper's conclusions are cautious — the researchers are careful to note that confirmation would require genetic analysis or further direct observation — but the footage is compelling. Taken together with the OCEARCH winter aggregation data, a picture is beginning to emerge: that somewhere in the warm waters of the western Atlantic or Gulf, great white sharks are quietly raising the next generation, far from the locations where they are most observed and studied.

Why This Matters Beyond the Headlines

Understanding where great white sharks spend the least-visible portions of their lives is not merely academic. Pupping grounds and juvenile nursery areas are the most critical habitats for any species — and the most vulnerable. If great white pups are born in areas that overlap with commercial fishing operations, recreational boating lanes or coastal development zones, that mortality has a disproportionate impact on population recovery.

The North Atlantic great white population is listed as Vulnerable on the IUCN Red List. Despite full legal protection in the United States and Canada since the 1990s, population recovery has been slow — reflecting both the species' extremely low reproductive rate (females are believed to pup once every two to three years, producing only two to fourteen pups per litter) and ongoing mortality from bycatch.

"We've been studying the parts of their lives that are easy to study — the summer feeding grounds," said Dr. Robert Hueter, senior scientist emeritus at OCEARCH. "This research shows us the parts we've been missing. And those missing pieces are probably where the keys to their survival lie."

A View From Mossel Bay

For those of us who work with great white sharks in South African waters, the OCEARCH study resonates deeply. We know from our own research partnerships that great whites in the Indian Ocean undertake similarly extraordinary migrations — crossing vast stretches of open water between South Africa, Australia and beyond. The ocean these animals inhabit has no borders. Understanding the full arc of their lives, across every season and ocean basin, is how we build the knowledge needed to protect them.

The secret winter lives of great white sharks have been hidden from us for as long as we've been looking. In 2026, the ocean is finally starting to give up its secrets.

Want to see great white sharks in their natural habitat? White Shark Ocean operates cage diving and surface encounters in Mossel Bay, South Africa. Visit whitesharkocean.com.

Frequently Asked Questions

Where do great white sharks go in winter?

According to the landmark 2026 OCEARCH study, great white sharks in the western North Atlantic migrate south and west in autumn when water temperatures drop below roughly 14°C. The majority travel to the Gulf of Mexico, concentrating particularly around the West Florida Shelf and Pulley Ridge — a submerged reef system about 250 kilometres west of Florida. There they spend the winter months in deeper water, with reduced movement and activity compared to their summer feeding grounds. Similar seasonal migrations have been documented for great white populations in South Africa, Australia and California.

How far do great white sharks migrate?

Great white sharks are among the longest-distance migrants of any fish. The OCEARCH study tracked individual sharks travelling up to 4,000 kilometres on their annual autumn migration from Nova Scotia and Cape Cod to the Gulf of Mexico. In other ocean basins, great whites have been recorded crossing entire ocean basins — one tagged female named Nicole was famously tracked swimming from South Africa to Western Australia and back, a round trip of approximately 20,000 kilometres, in under nine months.

Has a great white shark birth ever been filmed?

Possibly — and for the first time ever. In February 2026, marine biologists Carlos Gauna and Phillip Sternes published footage in the journal Environmental Biology of Fishes showing what appeared to be a newborn great white shark pup covered in a white oily film consistent with uterine fluid, accompanied by a large female. If confirmed, this would be the first ever footage of a great white shark being born in the wild. The researchers were careful to note the footage requires further confirmation, but described it as highly compelling evidence of a birth event.

Where do great white sharks give birth?

No great white shark pupping ground has ever been definitively identified anywhere in the world — making this one of the last great mysteries of shark biology. The species' extremely low reproductive rate and the deep, remote nature of their winter habitats have made direct observation extremely difficult. The OCEARCH Gulf of Mexico aggregation data and the Gauna/Sternes California footage both point towards warmer water areas as likely birth sites, but systematic confirmation requires genetic sampling and sustained long-term observation that has not yet been achieved.

How many pups does a great white shark have?

Great white sharks are viviparous — they give birth to live young rather than laying eggs. Litter sizes range from approximately two to fourteen pups, with an average of around seven to nine. Females are believed to reproduce once every two to three years, possibly less frequently. Pups are born at around 1.2 to 1.5 metres in length and are fully independent from birth. The slow reproductive rate means great white populations recover extremely slowly from any reduction in numbers, making every individual — and every pupping ground — critical to the species' long-term survival.