June is here. As well as marking the onset of the academic summer, June is recognized as Pride Month, a time when some celebrate the myriad manifestations of human sexuality.
But what about the other critters? Where’s the love? This month, I’ll share some other species’ practices and habits that don’t fit our preconceived notions of reproductive biology. Clutch the pearls! We’re going to talk about the birds and the bees.
Let’s begin with cuttlefish.
Cuttlefish are cephalopods, along with octopuses, nautiluses, and squids. Characterized by multiple arms surrounding a head (cephalopod translates to “head foot”), a muscular mantle (except the nautilus, which is the only one to retain a hard shell), and large brains, cephalopods are among the most fascinating creatures on the planet, and by far the most intelligent of the invertebrates, as defined by humans.
While octopuses get a good deal of media and pop culture attention, I find cuttlefish equally praise-worthy. Like their octopus relatives, they can change colors and patterns almost instantly, and dazzle with an array of flashy hues. In fact, they have the most dynamic and diverse color options of all the cephalopods.
I grew interested in these animals after my first and only encounter with a real cuttlefish at an aquarium in O’ahu, Hawaii. That little cuttlefish absolutely interacted with us as we walked back and forth in front of its tank. It would lower its eight arms downward, peer inquisitively at us with its curious, bulging eyes, then propel itself away, its arms swooshing outward and its delicate fins, which run alongside its body, fluttering like silken wings. Over and over, it would come back to us, as if we were the attraction that day. It took a lot of wifely persuasion to convince Joe that we did not need a pet cuttlefish.
As with other species, courting brings out some fascinating behaviors in rival male cuttlefish. They flash brightly. They pulsate. They challenge other males, rushing and fighting each other. And sometimes, they deceive.
One clever deception, seen in about 39 percent of male cuttlefish, is the ability to display male color patterns on the side of its body facing a female while presenting the other side of its body as female. “I’m just a female hanging out with the gals,” is the message to all but the object of his desire. This two-sided talent gives the gender-bender more time to seduce his crush as the rival males remain unthreatened by the presence of another male.
The giant Australian cuttlefish goes even further. When wooing, male giant Australian cuttlefish flash neon blues and purples, brilliant greens, ruby reds, and golden patterns of dots and lines. Chromatic dazzling is accompanied by posturing; a male will flare his arms in an attempt to look bigger, and show off his hectocotylus, a tentacle dedicated to delivering sperm, in front of his face like a healthy handlebar mustache. The larger males intimidate and chase away their smaller competitors.
Rather than feeling sorry for themselves, the little guys resort to trickery. These cuttlefish, known as “sneaker males,” go full-on drag. They pull in their arms and change colors to appear female, tucking their hectocotyli under their arms. In this way they are able to sneak right past the macho cuttlefish and mate with the females, who accept these sneaker males about 60 percent of the time, while the big boys battle it out with each other.
All that’s well and good, but there’s more. Refresh your coffee for this part.
The cuttlefish mating act is a head-to-head event. Males will “punch” packets of sperm right into the females’ mouths. Females store the sperm in specialized sperm cavities for up to five months. After mating with several males, the female cuttlefish will selectively fertilize her eggs, then attach them to sheltered rocks or crevices where they are then left to their own devices to thrive or die.
How a female remembers which sperm packets belong to which male is more than my human brain can comprehend.
In fact, I can tell you right where I was when I learned that cephalopods select stored sperm for fertilizing their eggs, just as I can tell you where I was when Auburn beat Alabama in the famous “Punt Bama Punt” 1972 Iron Bowl, when I heard Elvis died, and when Joe first told me he loved me.
If you were a polygynous female cuttlefish, mating with multiple partners, in the one and only mating season of your life, whose sperm would you select to best ensure the survival of your species?
Research by dedicated teuthologists, scientists who study cephalopods, indicates that females prefer the sperm of the “sneaker males.” Teuthologists hypothesize that crafty intelligence is a better marker for cephalopod success than flashiness and size. It’s brains over brawn for the giant Australian cuttlefish.
If you’d like to witness the giant Australian cuttlefish reproductive extravaganza, visit Point Lowly, Whyalla, South Australia between May and July, when hundreds of thousands of these splendiferous creatures come a’courting.
Mary Dansak is a writer and a retired science education specialist living in Auburn, AL. She can be reached at [email protected] and on Facebook at Little Green Notebook.