This post describes a dive at the “Pipeline” site, Nelson Bay, in late February. It’s not science, and not a dramatic tale, just 90 minutes or so of octopus behavior – one brief period in their complicated lives.
Dive conditions were good. I headed a little to the north-east, exploring. I came across a cluster of octopuses. The first had a good den with a bottle nearby (as they often do), and was very watchful. He’ll be “Bottle Octopus,” or O1.
He was arranged with shells around, peering out, and at least much of this peering was in the direction of the other behaviors that were going on. Most of those behaviors were a little way off, but I think he could probably see some of it. I kept going back and checking on him, and he was always there.
I realized there was another octopus pretty close by him, out in the open. He was burrowing into the sand, puffing up silt, moving slowly but causing a fair bit of commotion.
I estimated that he was about 1.5 meters from Bottle Octopus (1) at this initial stage, messing around on the flat. He unearthed quite a lot of shells. I don’t know if he found any food. He will be The Excavator, or O2.
A third octopus was about two and a half meters away from Octopus 1 and perhaps three or so away from the other. This one, Octopus 3, was dark, set up in a den.
I looped between the three for a while. Not much was happening. I thought I’d go and interact with someone, and chose Octopus 3. He had some interest in my metal rod, no interest in my hand. He left the den – I think I was a little bit too persistent. (I don’t reach out and touch the octopuses, but bring my hand or the rod within easy reach, to see if they’re interested.) He left and hung out nearby, might have come back, then jetted away. He went over fairly close to the Excavator (O2), but they didn’t interact. At this stage, the Excavator paid no attention to anyone. Octopus 3 went back to his den.
Another photo of O2’s wanderings at this stage:
Then I realized there was a fourth octopus. If you drew a rough line from O1, through O2, you’d get to another den a little further away, perhaps four or five meters. There was an octopus in this den who was very timid. If I came even somewhat close, he would retreat deep into his den, and I could just see his eyes. This was the Timid Octopus (O4).
I went back and checked out the others, and as I was coming back, I saw that an octopus – I am almost sure it was the Excavator (2) – was interacting with yet another, smaller octopus. That one was backing away from the scene while doing a split body pattern, with high contrast patterning directed towards the Excavator (2), who was not doing much in the way of color.
This new one was smaller and had a number of injuries along his front – scars. He produced some faded yellow colors, different from the others. He was active and mobile, but had taken some serious bites. This was the Injured Octopus (5).
Fish (leatherjackets, aka filefish) were hovering around the whole time. I noted that they were regarding this octopus differently from the others. Two or three of them were following the Injured Octopus (O5) closely, and they were willing, on at least one occasion, to try for a bite at him.
They hadn’t done this with the other octopuses. (One exception: a leatherjacket tried for a sharp nip at Octopus 3 during one of his jets.) I wondered whether the fish could tell that O5 was less formidable, given the injuries. He had also been timid in his interaction with the Excavator (O2), though this was not surprising as he was smaller.
I followed the Injured Octopus for a while, eventually lost track of him, and went back.
The octopus who, I said just above, was almost certainly the Excavator (2) now looked like he’d commandeered an old den. It might have been where he’d come from initially, but it was very close to the den of the Timid Octopus (4). It seemed more likely that the Excavator, in the course of his wandering, had come across an abandoned den that happened to be near where the Timid Octopus (4) was hanging out. I suspected that O4, given his timidity, would not have been interested in hanging out that close to another octopus.
This might be wrong – they might have been different sexes and the male, whichever it was, might have set up close to the other. But my tentative hypothesis is that the Excavator (2) made use of a pre-existing den site. The den did look a bit second-hand.
By now I had very little air left. I said goodbye and headed in.
As I came out and walked up towards the car, there were five or six big birds, cormorants I think, swimming together along the front of the breakwater, dipping their heads below, half-diving down occasionally, fishing, and chatting to each other.
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Notes:
Here is a rough map I drew at the time. (“Steam engine” is the Excavator. The numbers are distance estimates in meters.)
I am going to go through all the scraps of video I have and try to work out some of the sexes – above I am completely haphazard on that issue.
Some videos:
The Excavator excavating, with an observer: