Howdy,
Octopus bites are a fascinating subject and I hope you get lots of
responses. Keep in mind though that there's no such thing as a typical
octopus bite.
Before continuing, let me admit that I've never been bitten and that
I'd be just as happy to keep that record intact.
About a week ago, I attended a lecture by James Cosgrove M. Sc. of the
Royal British Columbia Museum. Jim's main area of study is the
behavior of GPO's (Enteroctopus dofleini) in the wild. For that reason
I think it's safe to say the he's p*ssed off more wild GPO's than just
about anyone.
At the lecture I got the chance to ask about octo bites and why some
species seemed more likely to bite than others. No answer to the
second question but he made some interesting points about octo bites
in general. Specifically, octos DECIDE to bite and, once that decision
has been made they then decide whether to inject a venom (often a sort
of tranquillizer but sometimes a potentially fatal toxin) or a
digestive enzyme or nothing at all. A simple bite from most of the
species discussed here probably wouldn't be much worse than you might
get from a parakeet or cockatiel. A bite with venom could vary a lot
in its effect; keep in mind that the venom is usually intended to
subdue but not kill a prey animal that's usually an invertebrate. IOW:
The venom isn't optimized for use on humans. A bite with digestive
enzymes is often really bad news. The enzymes used by the octo are
very powerful and there have been a number of cases requiring skin
grafts and other surgical procedures to repair the damage.
As an aside, I asked Jim whether he had ever been bitten by a GPO.
He's been studying this species for decades and could only recall one
near miss. He was trying to get a particular GPO out of its den and
the animal got hold of him with the suckers on a couple of arms and
was trying to pull him into the den (he wouldn't have fit). In order
to get free he had to abandon his dive glove to the octo. Since the
octo had no interest in an empty piece of neoprene he was able to
retrieve the glove after a few minutes and discovered that the GPO had
bitten a pretty big hole in it. Presumably, if he hadn't got his hand
free the octo would have bitten him but it should be acknowledged that
there are other possibilities

. Other than that he's never been bitten.
Further, the director of our center handles our GPO on a weekly basis
in connection to the cleaning of the tank and she's never been bitten.
OTOH: We no longer seem to keep a Red Octopus (Octopus rubescens) and
I suspect the reason is that she was bitten almost every time she
tried to work with one. O. rubescens bites can be most unpleasant as
can be seen in the story at this site:
Sorry, that's a dead link (404) Please note that
the story mentions two incidents with quite distinctive outcomes;
pretty small sample size but it does tend to support what Jim Cosgrove
told me about octos having total control over what, if anything, they
choose to include with their bite.
Venomously yours,
Alex