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2026 Cook Islands ROV Exploration

Feature

A Mega Find: Shark Teeth from the Deep Waters of the Cook Islands

August 1, 2026

A woman in a red sweatshirt wearing purple gloves holds a megalodon shark tooth collected during the cruise.

2026 Cook Islands ROV Exploration co-science lead Dr. Aurora Elmore and a megalodon shark tooth collected during the cruise. Image courtesy of NOAA Ocean Exploration, 2026 Cook Islands ROV Exploration. Download largest version (jpg, 699 KB).

A fossilized shark tooth encrusted with manganese is held by a purple gloved hand.

This fossilized shark tooth, encrusted with ferromanganese oxide, was collected during the 2026 Cook Islands ROV Exploration cruise. Image courtesy of NOAA Ocean Exploration, 2026 Cook Islands ROV Exploration. Download largest version (jpg, 729 KB).

While exploring in the southwestern part of the Cook Islands’ exclusive economic zone throughout the first half 2026 Cook Islands ROV Exploration cruise, we encountered polymetallic nodules each time we reached the seafloor. And on many of our dives, tucked within those nodules have been large fossil fish teeth.

Based on their size, with many measuring over seven centimeters (three inches) in length, the teeth likely belonged to megalodon sharks. Megalodons, or “megs” in popular culture, are considered to be the largest shark, as well as the largest fish, that ever lived. While they have been extinct for over 3 million years (save for in the movies), their teeth continue to provide us with valuable clues about the ocean environment.

Because fossilized fish teeth absorb trace and rare earth elements (REE) from the water column and seafloor upon sinking, analyzing the concentration of REEs such as neodymium trapped in the teeth can serve as a tool for tracking past ocean circulation patterns. Fish teeth are also often the nucleus around which polymetallic nodules form, with minerals such as manganese and iron slowly accumulating around the tooth, layer by layer, over millions of years.

Check out some of the shark teeth collected during the first half of the 2026 Cook Islands ROV Exploration cruise.

A shark tooth resting on the ocean floor amidst rocks and nodules.

This shark tooth was seen resting on the seafloor during Dive 09 of the 2026 Cook Islands ROV Exploration. At the time, the mission team was interacting live with Cook Islands Prime Minister Mark Brown, who guided remotely operated vehicles in the collection of the tooth. Image courtesy of NOAA Ocean Exploration, 2026 Cook Islands ROV Exploration. Download largest version (jpg, 936 KB).

A woman in a pink shirt poses with a shark tooth in front of a remotely operated vehicle.

Chloe Wragg, a senior technical officer with the Cook Islands Seabed Minerals Authority, poses with remotely operated vehicle Deep Discoverer and the largest shark tooth collected during the 2026 Cook Islands ROV Exploration cruise. Image courtesy of NOAA Ocean Exploration, 2026 Cook Islands ROV Exploration. Download largest version (jpg, 717 KB).

A woman in a pink shirt poses with a shark tooth and the manipulator arm of a remotely operated vehicle.

Tanga “TJ” Morris, a senior technical officer with the Cook Islands Seabed Minerals Authority, poses with the manipular arm of remotely operated vehicle Deep Discoverer and a shark tooth collected during the 2026 Cook Islands ROV Exploration cruise. Image courtesy of NOAA Ocean Exploration, 2026 Cook Islands ROV Exploration. Download largest version (jpg, 712 KB).

A large shark tooth being measured on a table, with a ruler for scale.

This largest shark tooth collected during the 2026 Cook Islands ROV Exploration cruise measured 13 centimeters (5 inches) in length! Image courtesy of NOAA Ocean Exploration, 2026 Cook Islands ROV Exploration. Download largest version (jpg, 987 KB).

Three smiling crew members pose with a shark tooth in the control room.

ROV navigator Jacob Stock, data engineer Rachel Simon, and video engineer Caitlin Bailey in the NOAA Ship Okeanos Explorer control room with a shark tooth collected during the 2026 Cook Islands ROV Exploration cruise. Image courtesy of NOAA Ocean Exploration, 2026 Cook Islands ROV Exploration. Download largest version (jpg, 1 MB).

A shark tooth held up against the sunrise on the ship deck.

Seven shark teeth were collected on several dives during the 2026 Cook Islands ROV Exploration cruise. The teeth will be analyzed to determine their chemical signatures, which can help scientists better understand changes in the ocean environment over time. Images courtesy of NOAA Ocean Exploration, 2026 Cook Islands ROV Exploration. Download left image (jpg, 702 KB). Download right image (jpg, 984 KB).

A man holds shark teeth up to his head like rabbit ears with the sunset in the background.

2026 Cook Islands ROV Exploration cruise co-coordinator Matt Dornback has a little fun with two shark teeth collected during the cruise. Rest assured, the teeth were handled with care and will be carefully processed prior to any chemical analysis! Image courtesy of NOAA Ocean Exploration, 2026 Cook Islands ROV Exploration. Download largest version (jpg, 530 KB).

A woman poses with a shark tooth and a remotely operated vehicle.

Gretchen Spencer, 2026 Cook Islands ROV Exploration cruise co-coordinator, introduces remotely operated vehicle Seirios to one of the shark teeth collected during the cruise. Image courtesy of NOAA Ocean Exploration, 2026 Cook Islands ROV Exploration. Download largest version (jpg, 794 KB).