New England Aquarium researchers spotted a little-known species of whale during a recent aerial survey.

Scientists photographed three True's beaked whales, believed to be two adults and a juvenile, during a mid-October flight over the Northeast Canyons and Seamounts Marine National Monument, which is about 150 miles southeast of Chatham, Massachusetts.

The aquarium says these "deep-diving" whales are a rare sight.

"People who maybe go out boating or something are not going to see these animals because they exist in deep water," aquarium research scientist and aerial survey coordinator Orla O'Brien told WBZ-TV. 

It's also a challenge for survey teams to spot them because they can hold their breath for "a really, really long time," O'Brien said.

"They'll kind of come up ... take some breaths, and then they'll be down for hours, so just the chances you see one are really small," she explained.

The National Oceanic and Atmospheric Administration says there is little information about True's beaked whales "due to the rarity of sightings at sea."

"Are they endangered? Are the populations in good shape?" O'Brien said. "We just don't have enough data on them."

The whales are bigger than dolphins and can weigh up to 3,000 pounds, but not much is known about their lifespan or reproduction habits. They will dive thousands of feet to the ocean floor in order to feed on squid.

"They're really interesting creatures," O'Brien said.

The recent survey also observed hundreds of other marine animals, including over 400 dolphins and seven fin whales.