Meanwhile, CTV News reports that two of the dolphins were killed in the attack. Dr. Lance Barrett-Lennard, a senior marine mammal scientist with Vancouver Aquarium, told CTV News that the attack is a sign that the marine mammal population of the area is beginning to return to healthier levels.

"It was crazy because by the time we drove down and parked, the whales were actually hunting -- fast, in and out," one witness told CTV Vancouver.

The American Cetacean Society states that orcas can be separated into three distinct population types: Resident, Transient and Offshore. Resident orcas will usually eat mainly fish, while Transient orcas will eat sharks, seals, penguins, and even other whales. According to CTV News, the orcas involved in the attack were Biggs, or Transient, orcas.

Orca attacks on dolphins are not uncommon. Just last year, photographer Jodi Frediani captured a series of photos in Monterey Bay, Calif. of a pod of orcas hunting a long-beaked common dolphin. She told Wired.com that once the dolphin was caught, the orca proceeded to share it with her two calves.