In 2011, Justine Allen and Derya Akkaynak were scuba diving in the Aegean Sea in coastal Turkey. They were recording video to study cuttlefish camouflage when they spotted a pair of the creatures begin mating. They got it on in the head-to-head mating position for about four minutes, and then the male cuttlefish stuck around to guard the female as she swam around the seafloor.
But all of a sudden, another male appeared. The date was over. An inky battle ensued, and the researchers caught it all on video—the first record of cuttlefish competing for a mate in the wild. They published their results this week in the journal The American Naturalist.
According to a press release, researchers have observed cuttlefish tangle with each other in tanks in the lab, but have never seen the sequence of events in the open ocean. Typically, after mating, the male cuttlefish escorts the female increase the odds that she’ll use his sperm to fertilize her eggs.
In this particular instance, the second intruding male moved in on the couple, chasing the first male away and escorted the female for a stretch, trying to convince her to mate. When the first male approached again, the intruder extended his fourth arm, dilated his pupils and darkened his striped pattern as a warning to back off.
After a few minutes, however, the first male zeroed in for the attack. After a vicious tussle, the first male emerged victorious, returning to the female.
“They have a whole repertoire of behaviors that they use to signal to each other, and we're just barely starting to understand some of them,” Allen, lead author of the study, says in a press release. “A lot of their fighting is done through visual signals. Most of these battles are actually these beautiful, stunning skin displays. It’s a vicious war of colors.”
Roger Hanlon, Senior Scientist at the Brown University’s Marine Biological Lab and Allen’s graduate advisor at the time says in the press release that the encounter is remarkable and something he’s been trying to record for over 20 years.
It turns out the interactions in the wild are a bit rougher than the researchers expected. “We were surprised at how violent and aggressive the behaviors actually were,” Allen tells Rae Paoletta at Gizmodo. “This has been observed in the laboratory before, but never in the wild. And when it has been observed in the laboratory, the fighting usually doesn’t get this aggressive...so for there to be so much ink and fighting was really one of the most surprising parts.”
The fighting and biting was also surprising since cuttlefish have so much to lose if they get injured. “Cephalopods are really squishy and vulnerable and tend to avoid physical fighting, because if they get scarred on their bodies, they have a hard time performing camouflage or signaling to each other,” Allen tells Paoletta.
But there is still more to learn. The wild encounter confirms some behaviors that scientists have observed in the lab, such as their fighting strategy. The basic idea is that the creatures escalate the fight at the same rate, until one cuttlefish clearly shows they’re tougher, causing the other one to back off. But to confirm that idea, they’ll have to film more cuttle-fights, which hopefully won’t take another 20 years to find.