A “strange” mass stranding of hundreds of pilot whales occurred in New Zealand. A charity that organized the rescue effort said on Sunday that seventeen whales returned to a large pod and were swimming off shore.

In a Facebook post, Project Jonah said they are watching the bay and hoping the pod swims into deeper water. The group also said that the larger pod and the 17 pilot whales were a few kilometers off shore Sunday. According to the organization, a few hundred volunteers were on hand in case more whales got into difficulty.

Mass whales beaching:

Over the past few days, two separate mass strandings resulted in more than 650 pilot whales beaching themselves along Farewell Spit at the tip of the South Island.

100 whales have been refloated by volunteers, more than 200 swam away unassisted, while about 350 have died, including 20 that had to be euthanized.

Re-stranded group:

17 whales re-stranded themselves after they were refloated. They were a part of a group of around 200 whales that were stranded Saturday. Volunteers and conservationists attended to them earlier Sunday, they were refloated at high tide.

Volunteer Jonathan Jones said that it’s really strange to seem such a majestic animal doing this.

Pilot whales are common around New Zealand’s waters, they usually grow to about 25 feet and.

Why do whales beach themselves?

Experts have several theories to the reasons why whales beach themselves, they could be chasing prey too far inshore to trying to protect a sick member of the group.

Farewell Spit is labeled as a whale trap. It has a long protuberant coastline and sloping beaches this makes it difficult for whales to swim away after getting close. It has been the location of prior mass whale beachings.

Herb Christophers spokesman of the Department of Conservation said that people seem to have an emotional attachment to marine mammals. They’ve been singing songs to them, giving them specific names, treating them as kindred spirits.”

Friday’s event was New Zealand’s third-biggest whale strandings in recorded history. The largest was in 1918, when around 1,000 pilot whales came ashore on the Chatham Islands. The second largest was in 1985 when about 450 whales were stranded in Auckland.

New Zealand has one of the highest rates of whale strandings in the world.