Posted by: Rob Viens | July 18, 2012

Bow Surfing with Dolphins

On the 18th of July the Beagle was racing southward with a pod of cetaceans heralding the way. Darwin’s description captures the magic of the experience nicely:

“We are driving along at the rate 8 & 9 knots per hour.— A wonderful shoal of Porpoises at least many hundreds in number, crossed the bows of our vessel.— The whole sea in places was furrowed by them; they proceeded by jumps, in which the whole body was exposed; & as hundreds thus cut the water it presented a most extraordinary spectacle.— When the ship was running 9 knots these animals could with the greatest ease cross & recross our bows & then dash away right ahead.— Thus showing off to us their great strength & activity.— Several flying-fish were skimming over the water; considering time of year & Latitude 31° 37′ S: Long 49° 22′ W, I was surprised to see them.” (July 18)

HMS Beagle with porpoises (ca. 1900 by Robert Taylor Pritchett) – note the studding sails extending out to the right and left of the Beagle‘s primary sails:

HMS Beagle by R.T. Pritchett

Southern Rightwhale Dolphins “porpoising” (from Wikipedia Commons)

Southern rightwhale dolphins

As explained in some detail in an earlier post (see A Porpoise Primer), I suspect that Darwin was talking about dolphins here rather than porpoises (the name was used more generically in his time).

There are over 30 marine dolphin species but not all of them are found in South American waters. Some species that Darwin might have seen off the cost of southern Brazil (not counting the larger dolphins such as pilot whales and orcas) include the long-beaked common dolphin, common bottlenose dolphin, southern rightwhale dolphin, Atlantic spotted dolphin, clymene dolphin, pantropical spotted dolphin, striped dolphin, rough-toothed dolphin, Risso’s dolphin, and Fraser’s dolphin. (South America is also one of the few homes of river dolphins, who spend their entire life in freshwater rivers (or brackish estuaries).

Clymene dolphin (from Wikipedia Commons)

clymene dolphins

As is common in his daily musings, Darwin poetically describes one of the rare treats of nature – in this case, the experience of watching dolphins riding the bow wave of his ship. (It almost sounds like he spent the entire day just watching,) This encounter would (I’m sure) have been even more beautiful on a sailing ship moving rapidly across the ocean, with the full force of the wind at its back.

Dolphins have probably been surfing the bow wave of ships since humans first went to sea.  There are even references to early Greek descriptions of dolphin bow surfing to back up that claim.  Furthermore, it is almost certain that this practice started long before humans entered the scene, as dolphins like to surf any type of waves (they are excellent body surfers).  Observers have even observed dolphins harassing large whales in such a manner that forces the whale to surge forward. The dolphins then quickly ride the surge before going back and taunting the whale into doing it again!

Dolphins surfing the bow wave of a modern cargo ship (taken from a ship moving at about 16 knots – posted to YouTube by dilligaf67)

Why do dolphins ride bow waves?  Well, the evidence seems to support the idea that they do it purely for  fun (something that is rather rare in adult mammals, and may be related to their intelligence). Whether fish are present or not does not seem to matter (so it’s not typically about finding food). And some dolphins have been observed heading back  to where they started at the end of the “ride” Maybe to “do it again”, like my young children say (several times a day :)).

Sometimes it really all is just about having a little harmless fun. (RJV)

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