Promiscuous Squid Puts Life at Stake for 3-Hour Sex Sessions
Sex can be exhausting, especially if you're at it for hours - something the dumpling squid knows intimately. The promiscuous cephalopod is short-lived and known for having many partners, and researchers have found that after their hours-long mating sessions, these squids have half their normal swimming endurance.
A team of researchers from the Department of Zoology at the University of Melbourne studied dumpling squid (Euprymna tasmanica) living in the waters of Southern Australia and found that the energetic costs of such an extensive mating ritual could lead to a shorter life.
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Male dumpling squid are opportunists, initiating mating at any chance they get and continuing until a point of exhaustion. These sea creatures already have short lives - lasting less than a year - and they spend their last few months mating with as many partners as possible.
There isn't much foreplay for these swimmers - the male simply clings to the female from underneath and holds her in place. After these exhausting mating marathons, both the female and male squid have lost so much energy that they can swim only half as long as before their romp, leaving them vulnerable to predators and less able to forage for food.
"We found that after mating, both male and female dumpling squid took up to thirty minutes to recover to their previous swimming ability," said researcher Amanda Franklin. "This suggested that the squid were suffering from temporary muscle fatigue."
To test their endurance after copulation the researchers caught wild squid and gave them an endurance test to determine their normal swimming abilities. They were placed in a tank with flowing water that acted like a squid treadmill, forcing them to keep up, reports Fox News. Their baseline stamina was compared to their swimming performance the next day after being paired up with a mate in a tank the next day.
"Our results were a little surprising as the degree of fatigue was similar in both genders even though mating looks more strenuous for males," Franklin said.
Scientists suggest this may be due to the way the males physically restrain them by gripping their body, reducing their access to oxygen, reports BBC News.
"We predict that during this phase of muscle fatigue, squid may hide in the sand to avoid predators until they have recovered. The cost to them in doing this of course is that they cannot forage for food or search for other mates at this time," Franklin said.
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