• TONMOCON VII Announced | MBL at Woods Hole | Apr 6-8, 2018
  • Thanks for visiting! TONMO is the world's greatest online cephalopod enthusiast community, with interactive content going back to May of 2000, and a biennial conference. If you'd like to join in on the fun, become a TONMO member -- it's easy and free. You can follow us on Facebook and Twitter for more cephy goodness.

female or male

Animal Mother

Architeuthis
Supporter
Joined
Sep 8, 2006
Messages
2,364
#2
3rd right arm. If it's the end is the same as the rest, female. If it's got a different end (no suckers, almost flat or blunt), it's called a hectocotylus, and the octo is a male.
 

shipposhack

Haliphron Atlanticus
Registered
Joined
Dec 16, 2005
Messages
672
Location
Laie, Hawaii
#3
It is hard to be sure until you see eggs or not, but males have a Hectocotylus, which is what they use to transfer sperm to a female. It is typically the 3rd right arm of the octo. The octopus will usually keep the end of his Hectocotylus coiled at all times to protect the tip which is where the opening to transfer sperm is. There are other features that could distinguish it (depends on species the octo could have any or none of these) that include larger suckers and that arm being a little shorter than the others.

Edit: Grrr... Animal Mother beat me to it
 

gjbarord

Sepia elegans
Staff member
Moderator
Joined
Feb 1, 2007
Messages
870
Location
Des Moines, Iowa
#6

Members online