It’s been about a week since I got back from photographing sperm whales (Physeter macrocephalus) in Ogasawara with friends Eric Cheng, Douglas and Emily Seifert, and Julia Sumerling.
There is a lot I want to write about the trip, but as a first priority, I went through my photos and tried to do something that I don’t think anyone else has done/ is doing…ID individual sperm whales using in-water photos.
The somewhat crazy idea came to me because:
(a) My humpback whale calf ID project in Tonga is going well, with interesting revelations and help starting to come in from other people; and
(b) We were fortunate enough to see a lot of whales in the water the first few days we were in Ogasawara, and I noticed that many of the sperm whales have what appear to be unique white markings on their bodies, particularly in the lower abdominal area.
At first, I wasn’t sure if the white markings were unique to the whales in this particular area, or whether all sperm whales have these markings. I’m still not entirely certain (since there aren’t that many in-water images of sperm whales), but after checking Hal Whitehead’s book about sperm whales, a copy of which Julia brought along on the trip, I saw that a few of the images in his book showed whales in other parts of the world with similar markings.
So I decided early on in the trip to try to take as many photos of the undersides of sperm whales as possible, and catalogue our cetacean encounters once I got home.
Here is the result (the video may take a while to download, so give it time to buffer if you have a slow internet connection):
In summary, I was able to identify nine individual whales, all of which I believe to be members of a group of relatively friendly whales…the ones that had the giant squid. There were almost certainly more whales in the group.
What also seemed to emerge from the pattern of encounters is that the whale that we eventually saw with the squid in its mouth may have been the matriarch or leader of this particular group, as she showed up in a large percentage of my photos, meaning she approached us relatively often.
ID-ing sperm whales is a lot more difficult than humpbacks. Humpbacks are surface-active whales, while sperm whales dive down hundreds, even thousands of metres…and they stay down. But still, it is possible to ID them, as this short video demonstrates.
Whether these IDs will come in useful over the long-term or not…only time will tell. If I get a chance to go back, I’m hoping to continue this endeavour, with the objective of seeing if it’s possible to document a consistent population and/ or frequent visitors to the area.
The video above is small, so it’s difficult to read the text. This is a PDF document (11MB) of the slides in the presentation, and this is a bigger Quicktime video file (640×360, 79MB…Do not click this link and try to open in your browser. Right click to download the file only if you have a good internet connection.). There’s also a .mp4 file available via iTunes.
Note: Photographs taken under permit.