BOSTON -- A horse that was swimming with its rider drowned off a West Barnstable beach Monday.

"Three people were riding horses down on the beach and they were also swimming with them," West Barnstable Fire Chief Joseph Maruca told the Cape Cod Times. "For some reason one of the horses got into trouble, and they weren't able to get it out of the water."

Horseback riding on Sandy Neck beach is common, according to park manager Nina Coleman. This horse still had its saddle on when its rider went into the water, which Coleman said is not common.

The horse threw its rider and its legs became tangled in the reins, Coleman told the newspaper. Its head was then held underwater by the reins.

"It's very unfortunate and it was such a fluke accident," she said.

The 17-year-old girl who was riding the horse was not injured. Maruca said he had never seen a horse drown before. "It's a unique incident for us to respond to."

The 4½-year-old horse was removed from the water by bystanders, according to veterinarian Marina Cesar, who examined it. It was then picked up by a front end loader and transferred to a flatbed truck for removal from the beach.