As someone who has been on the water a lot in several corners of the world over the past decade, I keep a list in the back of my mind of a couple of cetacean species I would love to see one of these, a generally pelagic or offshore dolphin species has eluded me, the Rough Toothed Dolphin. Long have I been enthralled by the Rough Toothed Dolphins prehistoric looks and social nature. This species was named for the ridges found on their teeth giving them a rough appearance. And as with many cetacean species we know relatively little about them. I had hoped to encounter these dolphins during sperm whale research in the tropics, but I was never in the right place at the right time. I found myself on the Big Island of Hawaii helping with an undergraduate marine biology course. I had helped with this class on a few other occasions, but never had a chance to get out on the water around the islands. This time, I was determined to change that. A small piece of me hoped that I would get a chance to finally see Rough Toothed Dolphins, but I shook that from my mind. It was unlikely to happen in a single trip to sea, and the worst thing to do is to set your expectations too high. The first Saturday morning came quickly field course assistance, a few students and I left the Harbor on a tour to explore Kona’s pelagic habitats just offshore. It is an amazing coastline where the shelf drops off to one kilometer deep just outside of the harbor and continues to slope down, far beyond that, where you would have to travel nearly 100 nautical miles offshore to reach those depths in places like Nova Scotia. Here they were, right beyond our doorstep. There had been a decent storm in the days leading up to this trip, so the sea was agitated and not as calm as one would typically expect, in the Big Island this time of year in terms of wildlife, it was pretty quiet. Hawaii rose out of the ocean to our port side as we traveled southwards on the lookout for marine mammals. Time sailed by, the further south we went, the calmer as the sea became and yet there was no sign of cetacean life. We approached C buoy, a floating marker anchored to the sea floor that serves as a fish aggregating device and a favorite fishing spot for both humans and marine life. Several birds circled above and near the buoy. We found an oceanic white tip shark. That was pretty cool. However, there were no blows glistening flanks or dorsal fins. While we were enjoying other marine life around C buoy, the captain got a message that some friends of his had seen a large aggregation of Rough toothed dolphins to the north near another buoy. My heart jumped in my chest. Could we possibly make it? As a whale biologist, I know just how quickly species can disappear into the blue. It was a bit of a pipe dream. We had a chat and decided to go for it, despite the time it would take to travel there. Fingers crossed.
After about half an hour, we arrived at F buoy bobbing and missed the swells I had prepared myself for the possibility that this was all one big wild goose chase. Moments later, I glimpsed these prehistoric looking pelagic dolphins for the first time.
They were everywhere, breaching, surfing in the waves, on the horizon, in all directions. I estimated approximately 40 of them, which I have been told is an abnormally large group for this particular occasion. Off the Big Island of Hawaii, they are typically seen in much smaller aggregations, model gray and white with pinkish undertones, they frolicked in the sea around us for more than half an hour before slowly moving further offshore.
These dolphins occasionally surfaced with their long reptilian rostrums above the water, and I have since learned that the unique pattern of white splotches around their mouth, sometimes are called lips, are used by local biologists for identification.
We certainly felt like we were living in a dream on the ride back to Port after over a decade of hoping to see Rough Toothed dolphins, that day had finally come. It would be remiss of me not to mention that we also encountered another cetacean that day, shortly after we left F Buoy for part of the way home, we are accompanied by bow riding Pan tropical Spotted dolphins, another beautiful, fairly common but underappreciated species. And so ends the short story of my encounter with Rough Toothed Dolphins. I can tell you that they were just as wonderful to see as I had imagined all these years, so strikingly prehistoric in their appearance, I truly hope that it does not take another decade before I see them once again.
-Elizabeth
This post was adapted from a voice recording in episode 72 of the Whale Tales Podcast, listen here.
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