Birds do it and bees do it, but have you ever wondered how snakes (ahem) get busy?
If you can believe this, some species — including a few verrry big ones — can procreate without having sex. That's called "parthenogenesis" and it's one of the many reproductive oddities we'll be exploring here.
To answer the question posed by our headline, we've got to make like a black mamba (one of the fastest living snakes, FYI) and cover a lot of ground. Welcome to the wild, wild world of dual penises, delayed fertilization, mama python incubators and springtime "mating balls."
It's no secret that snakes flick their tongues a lot. Doing so lets the reptiles pick up airborne chemical signatures, like the pheromone trails made by singles in their area. Male garter snakes, house snakes and racers, to name a few, have all been observed "trailing" mature females with this technique.
The strategy doesn't always work. Sea snakes, which — go figure — live out their lives as marine animals, can easily lose track of a would-be partner underwater. Besides, pheromone trails naturally degrade with the passage of time.
When partners meet, the courtship rituals can take on many forms. A 2014 paper about this subject, published in the journal PLOS One, describes such foreplay antics as "chin-rubbing," "tail quivering" and "coital neck biting."
In numerous snake species, the males wrestle each other to gain access to females. For North American rat snakes, that can take the form of each combatant rearing up and then trying to pin his rival's head to the ground.
No snake has longer fangs than the Gaboon viper, whose venom-dispensing teeth can grow over 2 inches (or 5 centimeters) in length. Come breeding season, their males not only wrestle but aggressively strike at one another. However, the snakes do this with closed mouths, keeping those infamous fangs at bay.
When it comes to actual intercourse, two's a couple, but three or more is a crowd.
Garter snakes, copperheads and anacondas all form the occasional "mating ball" or "breeding ball." We'd love to tell you this is some kind of elegant dance. But it's not; mating balls are writhing heaps created when several males all swarm over the same female in an attempt to get her pregnant. More than a dozen participants may be involved.
The reproductive organs of both sexes are housed in the cloaca, an orifice whose slit-shaped opening is located underneath the tail.
Incidentally, male snakes and lizards have two penises apiece. The reptiles are endowed with a paired sex organ called the hemipenes; there's a right hemipenis and a left hemipenis, each connected to one of the testicles.
Only one penis is used during the act of sex. But that doesn't mean its counterpart never sees any action. Penis No. 2 could very well come into play if the male finds himself a second mate shortly after coitus.
Snake schlongs are often covered in little spikes or hooks. These may enable the males to prolong sexual intercourse, or do a better job of hanging onto their partners while in the throes of passion. (Not always an easy feat for legless animals.)
To improve his chances of siring offspring, a male red-sided garter snake will clog his bedfellow's nether regions by secreting a thick, gelatinous "plug." A temporary barrier, the plug keeps his sperm from spilling out, and it blocks rival males from leaving their sperm behind.
"Hiss" and Hers
Rest assured, female snakes have some tricks of their own.
Using pockets of folded tissue, a snake of the fairer sex can keep sperm isolated — but still viable — inside her body for very long periods, proactively choosing when to let them fertilize her eggs.
In 2005, a western diamondback rattlesnake who'd been living alone in captivity rendered herself pregnant and gave birth to a litter of offspring. To accomplish this, the mother reptile used sperm she'd held on to for roughly six years!
Sometimes, males aren't needed for reproduction at all. Another snaky superlative belongs to the green anaconda; it's the world's heaviest snake, weighing upward of 440 pounds (200 kilograms). Genetic testing reveals that females of the species can practice parthenogenesis, impregnating themselves with no male contact whatsoever.
The Next Generation
Here's a key difference between pythons and anacondas: The former lay eggs while the latter give birth to live young. Other live-bearing serpents include rattlesnakes and garter snakes.
Upon laying a fresh batch of eggs, a mother python will wrap her body around it. That loving squeeze keeps the clutch from losing too much water — and promotes healthy yolk development. Very frequently, the devoted parent remains coiled until the eggs hatch.
Egg-sitting is one thing, but it's pretty rare for snakes to take care of their actual babies. Female pit vipers thus deserve special recognition. Multiple species of these venomous reptiles are now known to watch over their newborn progeny for several days after the little snakes first come into the world.