Octopus Sex Updated, With Correction
The Octopus Kama Sutra
In a post from Curacao on octopus sex, the text was misleading in one important respect, and wrong in another. Here’s the video that inspired the post: (click video twice) https://richardcfrancis.substack.com/p/octopus-sex-its-complicated.
First the misleading part. I described the mating as face to face. As Justin Rhodes, the videographer, noted, it’s not obvious that octopuses have faces. A face, as generally construed, has on it eyes, nose and mouth. Of these features, the eyes are the only one present on an octopus head. We might consider the nose optional, but the mouth is an essential facial component. The octopus mouth, though, is centered underneath the body, at the base of the legs. On the outside of the mouth is a formidable beak. The beak is used to subdue and dismember prey, and in aggressive interactions with other octopuses. So eyes don’t a face make.
I should have described the octopus mating in the video as eye to eye. I erroneously likened this eye to eye to a description of an unusual mating behavior reported by Roy Caldwell for a different species. But what Caldwell described was actually a beak to beak mating, which is noteworthy because of the potential danger posed in exposure to a lethal weapon.
Since the original post I searched the literature more systematically for information on octopus mating behavior, while posting on different subjects. I found it to be even more complicated, and hence interesting, than I imagined. What follows is some of what I learned.
Until quite recently, virtually all reports of octopus sexual behavior came from observations in captivity, a distorted picture of octopus sex in the wild. But recently scientists—and amateurs—have taken to the field to observe octopuses mating in the natural setting. And, it is even more complicated than I suggested in the original post.
One mating position, described in the previous post, is side to side. This is also called distance mating because the male doesn’t have to be close to the female to transfer his packet of sperm with his mating arm. Sometimes this method is used when the male and female occupy adjacent shelters and cannot even see each other. This mating style can be brief (dump and run) or it can last for many minutes.
For the second mating method the male positions himself on top of the female from behind and extends his mating arm under the female’s mantle from above. This type of mating behavior, called mounting, can last for hours.
The third mating method, as described by Caldwell, is beak to beak (https://doi.org/10.1371/journal.pone.0134152). To accomplish this the pair approach with arms spread, and for brief periods, at least, attach suckers to each other’s (complimentary?) arms. Here’s a video: (Click twice. After video hit the back-a-page button to return to this post.)
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(I have seen no account as to how the male manages to deposit his sperm packet while in this position.) Since Caldwell’s report, at least one other species has been documented to do the beak to beak (doi.org/10.7717); this number will no doubt grow as field investigations intensify. Here is a mating, that was interpreted, mistakenly, I think, to turn into a fight. (On this and the videos that follow I advise you to turn off the sound. The music is uniformly dreadful and only detracts):
I would interpret this, rather, as a continuation of mating that becomes beak to beak. Octopus mating is often aggressive and can be difficult to distinguish from a fight. Here is a true fight, unless it’s the most passionate octopus mating ever recorded:
What I have not been able to find is any report or recording of octopus mating in the eye-to eye position seen in the video from Curacao. Here is one putative face to face, and hence eye to eye mating, but it looks to me like an attempted mounting.
I will keep digging on that front because I suspect that the mating behavior in Justin’s video is not unique, but just one other position in the octopus Kama Sutra.
This video may record yet another position: female on top. (To view the video click “Watch on YouTube” twice. Skip to 2:50 for the main action.)
I suspect that this may also be a case of sexual cannibalism. Suffocation, rather than beak damage, seems to be the means to that end (https://doi.org/10.1080/10236240701661123).
It is important to emphasize that these mating behaviors aren’t species specific. A number of octopus species, including the giant Pacific octopus (Enteroctopus dofleini), are known to adopt at least two positions (doi.org/10.7717; 5501b1d60cf231de076ae7d2.pdf. And it is suspected that this is true of all or most species. A female usually mates with several males by whichever means. Males, in turn, mate with several females. Octopuses are not only sexually versatile, but they are also quite promiscuous.
Male octopuses seem to discriminate when choosing a female with which to mate. One criterion is size. Males prefer large females. On the other side, females do not seem to discriminate among male suitors, accepting all comers (https://doi.org/10.5343/bms.2019.0045). This is the opposite of how mate choice works in most animals: Females tend to be more discriminating than males, especially when they invest as much energy in eggs and brood care as female octopuses do (10.3389/fphys.2019.01035).
It seems likely that female octopuses do discriminate but in more subtle ways (https://doi.org/10.1093/mollus/eyw045). Also, it should be noted that females may make post-copulatory choices, in choosing which sperm packets to use (https://doi.org/10.1093/biolinnean/blab096). As I indicated in the earlier post, octopus copulation doesn’t result in immediate fertilization, rather, the sperm packets can be stored. Female octopuses can also store those sperm packets for up to ten months (https://doi.org/10.1016/j.aqrep.2023.101472). Can she remember which is which? Given what we know about octopus intelligence, it wouldn’t come as a surprise.