A group of whale watchers in Dana Point, California, captured a rare sight on Monday: a migrating gray whale giving birth.

The mother whale successfully welcomed her calf to the world in front of a boatload of whale watchers on tour with Capt. Dave’s Dolphin & Whale Watching Safari.

Gray whales experience one of the longest mammal migrations (a 10,000 to 12,000 miles round-trip along the west coast of the U.S.). It is not rare for gray whales to give birth during this journey, but the voyage’s length makes it a difficult sight to capture on camera.

Capt. Dave’s Dolphin & Whale Watching Safari

grey whale gives birth in front of tour group

Anderson and his crew had never witnessed a wild whale birth in their 25 years of whale watching until the gray whale decided to treat them to the experience on Monday.

“The mom was gently lifting the calf to take breaths, while the calf seemed to be resting on her back. In other moments we could see the calf’s floppy fluke, as this newborn calf was learning to swim,” Capt. Chase Moore with Dana Wharf Sportfishing & Whale Watching saidwhile sharing his experiencewatching the whale birth withThe Orange County Register.

Gray whales travel from their feeding grounds in the Bering and Chukchi Seas near Alaska to the mating and birthing lagoons of Baja California, Mexico. The whales seek the lagoons as they offer protection from predators such as orcas and provide warm water for calves who have not yet built up a thick layer of blubber.

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At birth, the calves are about 15 feet long and gain over 50 pounds daily, feeding on their mother’s milk. Gray whale mothers can lose 30% of their body weight nursing one calf.

source: people.com