Hanlon, Roger T., Michael R. Maxwell, and Nadav Shashar. 1997. Behavioral dynamics that would lead to multiple paternity within egg capsules of the squid Loligo pealei. Biol. Bull. 193: 212-214.

Video sequence of an extra-pair copulation by a large lone male Loligo pealei. At the start of the segment, the female is in the center of the screen, just to the right of the egg bed. Her paired male is just above her. As she begins to place her arms into the bed, a lone, large male darts in from the left, grabs her mantle, and proceeds to copulate in the parallel position. Seven seconds after first grabbing her, he reaches in to his mantle cavity with his hectocotylized arm and transfers a spermatophore to the female's mantle cavity. After 14 s of copulation, the female's paired male starts to wedge himself between her and the copulating male. Nevertheless, the copulation lasts for a total of 28 seconds, which is a typical duration for parallel copulations.

Video sequence copyright © by Nick Caloyianis and Clarita Berger.