I’m Ever Upper Class High Society
God’s Gift To Ballroom Notoriety
I Always Fill My Ballroom
The Event Is Never Small
The Social Pages Say I’ve Got
The Biggest Balls Of All
–AC/DC, “Big Balls”
The zoology world is atwitter this week with news from the world of insects. Stop the presses! We’ve discovered the animal with the largest testicles in proportion to its body! Yes, it’s the Tuberous Bush Cricket, a katydid with huevos that make up 14% of its body weight. To put that in perspective, fellas, it would be like hoisting around 11 lb prairie oysters. The human head is 8-12 lbs, so imagine dragging your own head around in your nutsack. You’d literally need a wheelbarrow.
I’m rarely one to jump on bandwagons when it comes to the latest news, but how could I resist this little nugget about enormous McNuggets? It gives me yet another excuse to talk about insects and sexual selection. We’ve already discussed the mystery of the mammalian penis, so it’s about time we devoted some thought to our jungleberries, as well. I want to explore the reason for diversity in the size and shape of bollocks in the animal world. And I want to test my writerly skills to see if I can write an entire article about fuzzy danglers without using the same euphemism for “testicles” twice.
The first thing you must ask when you hear about enormous family jewels is, Why? The “why not” is easy to imagine, if you consider the human-head-in-a-pillowcase analogy above. For an animal that jumps for a living, extra cargo is usually unwelcome. So there are really only two ways to use such majestic marbles: either having sex with many females in a row, or busting a really heroic nut. In the battle for sperm supremacy, a greater quantity of sperm released in a promiscuous female can greatly improve your chances of paternity, the way more tickets in a raffle improves your chances of winning the prize. But in the case of the cricket, it’s a matter of quantity over quality: the cricket releases less sperm per mating, but mates with more females. This insectoid Wilt Chamberlin doesn’t put all his sperm in one basket.
That’s not the case across the animal kingdom. In 1970, the British biologist Geoffrey Parker proposed the “sperm competition theory,” which states, among other things, that huge stones should produce huge quantities of sperm for the purpose of beating rivals’ sperm by sheer quantity. This is the case with rodents, most of which have notoriously oversized wank-tanks because females will mate with many males once they go into estrus.
So female promiscuity is the primary factor in the size of your scallops. In more promiscuous species, such as squirrels, they’re big in order to blow a big load. In very promiscuous species, such as the bush cricket, they’re even bigger in order to inseminate more females. It’s the difference between going “all in” and hedging your bets; one has a bigger pay-off, and one has safer odds. If that’s true, then monogamous or polygamous species in which sperm competition is all but eliminated ought to have cute little yongles, or “low relative testes weight.” And they do! Gorillas, for example, have replaced sperm competition with regular competition — a silverback has all mating rights to his band, and will savagely beat any other males who think otherwise — and as such, have a 2-inch penis and 1 oz. prunes. Why have impressive junk if your paternity is assured?
For those animals for whom paternity isn’t assured, they have to battle it out in the oviduct. And there, it helps to not only overpower your rivals with sheer numbers, but also have superior firepower. For example, many insect species actually produce two different kinds of sperm: fertile eusperm, and sterile, “helper” parasperm. In species with heteromorphic sperm, the “helper” sperm serve as wingmen for their fertile brothers, creating a sort of protective entourage which help their hero proceed to the egg without interference from the sperm from rival males. In the wood mouse, spermatozoa have hooks which help them attach to one another to create “trains” which power through the fray. Imagine, sperm that are built like Chinese dragons and congo lines! Some animals have taken the “longer is better” idea to its literal conclusion: super sperm. The fruit fly, who held the “largest nards” prize before the bush cricket with witnesses about 10% of its total body weight, uses them not to contain more sperm but longer sperm. Coiled up in their whackers are sperm that stretch out to 2.3 inches: 10,000 times longer than our sperm, and 20 times the fruit fly’s own size. When fruit fly sperm fight for the egg, it looks like anacondas trying to strangle each other. Horrifyingly, fruit flies can release fifty of these leviathans at a time, and their bolos hold up to 800 at a time. For reference, fellas, try to imagine that your Yankee Doodles contained, instead of billions of spermatozoa, only 800, but each one was 116 feet long.
And what does the size of our yo-yos say about us? (And yes, I started making up my euphemisms about a paragraph ago.) Human fuzzy dice fall somewhere between the swinger bonobo’s and the prudish gorilla’s, suggesting that we are made to be only semi-promiscuous. Interestingly, a man’s sperm production — and thus, the relative weight of his Balzac — is influenced largely by the presence or absence of his mate. Two men forgo sex for a week: one whose wife is away at a corporate retreat, and one whose wife is sick with the flu. Whose sperm count is higher? The one whose wife could have been boning her boss. Evolution has prepared us against the threat of infidelity by endowing us with larger grocery sacks and emergency sperm production sessions. Our pool pockets are only as large as our cheating hearts.