Walk on the Wild Side
Unusual mating behaviors highlight the lives of various species
IT'S OBVIOUS that animals of all sizes and varieties reproduce. But when you stop and think about this delicate subject, there are some pretty tough obstacles that our friends in the animal kingdom have to overcome to "get the job done." How does a frisky porcupine mate without maiming his partner? What's the "secret weapon" that male butterflies use to attract their forever-flying females to the boudoir? And did you know there's one denizen of the deep that begins life as a perfectly functioning male but after a year or two decides to switch sexes and become a female … perfectly functioning of course! The six stories that follow will educate and entertain you as to what is really going on out there in the animal kingdom … when no one is looking!
In Hot Pursuit
What's the best place for a male polar bear to meet a potential mate? The experts recommend going to a prime seal-hunting spot. But finding such a spot is only the beginning of the challenge
One reason a male polar bear must work overtime for a date is that females of the species don't breed every year or even every other year. A female polar bear usually breeds only once every three years, which means that males outnumber eligible females three-to-one at the start of breeding season in the spring.
So competition for female attention is fierce, and males must fight one another, sometimes viciously, for the privilege of mating. Further complicating matters is the fact that female polar bears enjoy a good chase and will lead pursuing males across the ice for miles and miles. In some cases, a chase can cover more than sixty miles—not for the timid or the weak of heart.
Under Lock and Key
Good news for folks who lament the demise of chastity belts: The devices are still quite popular in the insect world.
The purpose of a chastity belt, remember, was to prevent intercourse. A sphragis accomplishes the same feat. What's a sphragis? It's the white pouch hanging from the abdomen of a Phoebus Parnassian butterfly—a female Phoebus Parnassian, to be precise. The male of the species secretes it while mating—it contains sperm and some nutrients—and the substance hardens upon contact with the air.
Once in place, the sphragis keeps the female from mating again. Yet it doesn't interfere with flying or with the laying of eggs.
It's the time of year when porcupines are feeling frisky. But that's not the real news. The real news is that porcupines are able mate without inflicting serious harm on one another.
The porcupine, of course, is known for its sharp quills—excellent for self-defense but intimidating for a suitor. One misstep and … ouch! Thus it's important not to surprise one's partner. First, the female must relax its quills, and then the male must squirt the female with high-pressure jets of urine. These are a few of the steps in one of nature's more elaborate mating rituals.
And if the encounter is a success, a little porcupine appears seven months later. Fortunately for the mother, the infant is born in a placental sac, and its short quills are soft for the first half hour or so of its life.
Despite their miniature size and their preference for dark places, fireflies receive a lot of attention when summer arrives. Their remarkable green and yellow flashing lights have a hypnotic effect on people. Children in particular are drawn to fireflies. But the same throbbing glow that attracts youngsters can lead male fireflies to their deaths.
In warm-weather months, especially where open meadows and forests coexist, the adult male fireflies of most species set out on mating flights in the evening hours. The females, meanwhile, await their mates in the foliage, blinking seductively. The task for each male is to find an unmated female of its own species. It's critical that the female be unmated because in many firefly species the females change through internal chemistry into man-eaters once they successfully mate. Thereafter they use their blinks to attract meals. Some females even imitate the idiosyncratic blinking patterns of other species in an effort to attract as many unsuspecting males as possible.
Underwater Gender Bender
Looks can be deceiving. The mild-mannered dock shrimp, for example, doesn't appear at first glance to be a creature with a noteworthy sex life. Yet the dock shrimp undergoes one of the most remarkable sexual transformations in the entire animal kingdom.
A marine arthropod that can be found in bays, estuaries, and even some tide pools on the Pacific Coast, the dock shrimp begins life as a male. And for a year or two it functions as a male, mating with female dock shrimp and providing them with sperm. Then, sometime in its second year, the dock shrimp transforms into a female, complete with its own eggs, and soon proceeds to mate with young male dock shrimp and produce offspring.
When it comes to seduction, even Don Juan himself can't compete with male Queen butterflies. But it's not a sport for these insects and others like them; it's a matter of survival.
That's because the female of the species, left to its own devices, tends not to cooperate with its suitors. Rather than pausing long enough for a male to position itself for mating, the female keeps flying. Fortunately for the male, it possesses a not-so-secret chemical weapon: pheromones.
These pheromones are released from small brushlike structures called hair pencils on the male's abdomen. When the male flies in front of a female in an attempt to seduce it, the hair pencils protrude and waft their chemicals in the female's direction. The female becomes entranced—more subdued than usual and more amenable to amorous advances.