A tour company off the coast of Oahu, Hawaii was surprised to be greeted by a pod of rare false killer whales, KHON2 reports.

Wild Side Specialty tours posted on Youtube a fascinating video of the encounter (below), which was recorded by tour crew member Elizabeth Hartford. False killer whales resemble killer whales (Orcinus) but are members of the dolphin family in a different genus (Pseudorca).

The creatures in this video are from a small, endangered, localized group of false killer whales that live only among the main islands of Hawaii and are genetically distinct from others of their kind.

“Because of their isolation, they have become their own distinct population,” Hartford told KHON2. She also told the news outlet that the pair seen in the video are a mother and her calf, and that they were encountered at a depth of about 1,500 feet.

The Specialty Tours Youtube page notes that while these creatures share a few things in common with the better known killer whale, or Orca -- similar skulls, lifespan, and breeding patterns -- the two are yet very different.

For instance, false killer whales, the tour groups says, will rarely attack mammals.

The Hawaiian false killer whales, such as those seen here, are considered endangered, with only an estimated 150 of them living amid the islands.

Of course, it's the "smile" early in the video that's really grabbing people. Perhaps the animals were warming up to the visitors in their waters.

via KHON2. Hat tip Underwater Times.