Dolphins and whales: interspecies play?

January 26, 2012 • 11:08 am

Via Treehugger and the Science Bulletin of the American Museum of Natural History comes an unusual report of bottlenose dolphins (Tursiops truncatus) sliding down the noses of humpback whales (Megaptera novaeangliae), an observation originally reported two years ago in a paper by Deakos et al. The behavior was seen twice (nice to get a paper out of about ten seconds of observation!). Here’s a video version of the report:

Here’s one observation described in the paper:

At 1427 h, two adult-sized dolphins (approximately 3 m in length) reversed direction and approached the humpback whales. The dolphins positioned themselves directly in front of one humpback still at the surface and appeared to surf the pressure wave created by the whale’s head as it swam. The two dolphins could be differentiated since one of them had a distinctive cookie cutter shark (Isistius brasiliensis) bite on the right side of the body and a notched dorsal fin. During the next two breaths by the same whale, each dolphin independently was seen lying across the whale’s rostrum as it surfaced, oriented perpendicular to the whale’s body. At 1430 h, the whale stopped and slowly raised its rostrum upward while lifting the well-marked dolphin out of the water (Figure 1a). Once completely clear of the water, the dolphin remained arched, on its side, balanced over the end of the whale’s rostrum (Figure 1b). The dolphin appeared to cooperate, with no discernible effort to free itself or escape. When the whale was nearly vertical, with its eye nearly breaking the water surface, the dolphin slid down the dorsal side of the rostrum (Figure 1c) while swinging its flukes upward (Figure 1d). This entire lift sequence lasted about 3 s, ending when the dolphin entered the water tail first.

A bottlenose dolphin slowly lifted out of the water by a humpback whale 1.8 km off the northwest coast of Kauai, Hawaii, on 25 January 2004 (photos by L. Mazzuca)
A bottlenose dolphin lifted repeatedly out of the water by a humpback whale about 800 m off the northwest coast of Maui, Hawaii, on 25 January 2006 (photos by M. Deakos)

What in the world is going on here?  The authors suggest a number of hypotheses:

  • The whale is pwning the dolphin.  Dolphins are known to surf the “pressure wave” in front of swimming humpback whales, and this could piss off the whale. The lifting of the dolphin could result from a head lunge by the whale, and head lunges are known to be part of the whale species’ aggressive behavior. The authors discount this because the head lunge was so slow, and the dolphin didn’t appear to flee it.
  • The whale is helping a distressed dolphin.  This is called succorant behavior, and has been seen in other marine mammals, though it’s very rare in baleen whales. The authors discount this because the dolphin didn’t appear injured or distressed. Also, if the action was merely a maternal response by a misguided female humpback whale (sex was not determined), that wouldn’t explain the dolphin’s “cooperative” behavior.
  • They’re playing!  Both bottlenose dolphins and humpback whales have been reported to engage in play-like behavior.  The authors suspect that this is the most likely explanation—that “social play” was initiated by the dolphin, perhaps stimulating a maternal effect on the part of the whale.
At the risk of anthropomorphizing, I see no reason why species like these, which have complex brains, couldn’t simply want to have a bit of fun.  Of course such play might not just be pure fun, but also form of socialization, bonding, or learning when it’s performed within a species.  But I do think dolphins wanna have fun.

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Deakos, M. H., B. K. Branstetter, L. Mazzuca, D. Fertl, and J. R. Mobley, Jr.. 2010. Two unusual interactions between a bottlenose dolphin (Tursiops truncatus) and a humpback whale (Megaptera novaeangliae) in Hawaiian waters. Aquatic Mammals 36:121-128.

32 thoughts on “Dolphins and whales: interspecies play?

      1. Would you two stop spouting off!

        You think cetaceans do puns? Are they a sign of true intelligence, or a sign that we have a long way to go in that department?

  1. “I’m from what, on your calendar, would be the late 23rd century. I’ve been sent back in time to bring two humpback whales with me in an attempt to repopulate the species.”

  2. Another possibility is that the whale is the dolphin’s pet. Dolphins are supposed to be pretty intelligent. Maybe it’s just as well they don’t live on land. I’m already owned by two cats.

  3. My favorite quote from Douglas Adams’ The Hitch-Hiker’s Guide to the Galaxy:

    “For instance, on the planet Earth, man had always assumed that he was more intelligent than dolphins because he had achieved so much – the wheel, New York, wars and so on – whilst all the dolphins had ever done was muck about in the water having a good time. But conversely, the dolphins had always believed that they were far more intelligent than man – for precisely the same reasons.”

    1. I get a lot of mileage out of this too. It’s a nice, gentle way to remind people that maybe we’re not sure what we mean by “intelligence” just yet. And people almost always get a chuckle out of it.

  4. Wanted to read more about it, but hit the Aquatic Mammals paywall. Gonna have to go mug a university student for his ID again–though I think the police are starting to catch on . . .

  5. Is it possible that this is a good way for the dolphin to get a good back-scratch? Don’t know what’s in it for the whale, though.

  6. I think that you are right. What we call play in humans is essentially training for real life. The fact that we continue to play as adults could be preservation of that behaviour (infantilism?) in later life, or because adults have to be able to react at a play level with children, only sometimes we substitute other adults for children. Therefore I see no problem in call this play.

  7. Another hypotheses could be highly evolved Photoshop implemented in an elaborate hoax. If real,the behavior could have developed gradually from the dolphin accidentally, partially stranding on and sliding off of the whale to “wow, let’s try that again”.

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