Migrating Naturalist: Mysterious Romance

No one in the world has ever seen humpback whales mating. And this is not for lack of trying, as researchers have been striving to witness this key event since research began over 30 years ago. It is assumed that humpbacks mate when they are in Southern waters, around the same region that they give birth to calves. This fits in with their estimated gestation period of 11-12 months, and would parallel the mating seen from grey whales near the Baja peninsula.

On February 26th of last year, our HWRF team had the excitement of witnessing what we believed was the first ever humpback mating event. We had been observing a very active competitive grouping a few miles North of Kaho’olawe, shortly after almost being crushed by a chin-slapping humpback male (recounted in “Too Close For Comfort”). We were lucky enough to have an underwater photographer on board that day, and as the whales began circling near the surface, we seized the chance for the diver to record the action underwater. To our surprise, she enthusiastically relayed with hand signals that more than one of the males had a visible penis extrusion, something that can be invisible from the surface, but is quite hard to miss underwater. As we eagerly reviewed the photos at the end of the day, we were thrilled to see evidence of what we believed must be mating. Unfortunately, after more in-depth examination, it was determined that the animal we had assumed as the female, was in fact one of the competing males. Interesting behaviour without a doubt, but certainly not any kind of successful reproductive mating.

This year as we celebrated our 1-year anniversary of this discovery, we found ourselves working in the exact same area as last year, observing yet another thrilling competitive group. Amazingly, as the whales began to perform the same mid-competition milling behaviour and we dropped our diver into the water, the males began to surround the female at the surface. Unfortunately, the moment lasted only seconds, and before we were able to get underwater footage, the group suddenly shifted into rapid surface travel. Consequently, we were unable to obtain the elusive footage we so longed for, but I maintain hope that the mysteries of humpback reproduction will be revealed very soon. At the very least, these encounters provide valuable evidence which may drastically alter the previous conceptions on how humpback mating occurs, and could provide a whole new direction for future studies on this behaviour.

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