Natural Human Sex Change

Last week I included humans in my list of animals known to have undergone natural, midlife sex changes. Well, sorry to disappoint: I wasn’t referring to some secret cabal of Tibetan monks who have trained themselves to retract their private parts at will, nor to some college kid who has mastered the ultimate party trick (assuming disappointment is your reaction to that sort of news). Nor is what I’m talking about, of course, a common, evolutionary mechanism like the clown fish’s or the sheephead’s. But it does happen, and that’s worth looking into.

Usually, the switch is from female to male– partially or completely. Such is the case in people with a condition called “congenital adrenal hyperplasia,” who lack an enzyme needed to make certain hormones. Specifically, these folks end up low on cortisol and aldosterone, while androgen, a male sex hormone, just keeps pumping away, filling their minds with thoughts of ESPN and fart-lighting contests.


Girls with the disorder will usually still have normal reproductive organs, but they might find themselves with facial hair and a failure to menstruate. Boys have it almost as bad, suffering from “deepening voice”, “enlarged penis”, and “well-developed muscles.” No, but really, they are also “shorter than normal”, so as a short person, I urge you not to take their plight lightly.

Okay, so a few girls might wake up looking like Tom Hanks in Castaway. Surely it can’t go the other way– there’s no case of a guy just up and sprouting breas– oh of course there is, just look. A father of five in UK, a pub singer, no doubt a manly man in his time, started developing smooth skin, breasts, and even hot flushes. Blood work shows he has an abnormally high level of estrogen, but nobody is really sure why. My theory is that 4+ kids is enough to break anybody’s spirit, and after that it’s like, why even bother restricting my estrogen development anymore, you know?

depressed dude

Regardless of the reason, there you have it: it is completely natural and probably, in fact, reasonable to fear that you will wake up in the middle of the night and find yourself transformed into the opposite sex, Kafka-style.



Genetic Sex Change: Gender Bending Animals

If you’re like me, you’re a human being with naturally defined, unchanging genitalia. I mean, chromosomal sex-determination, am I right, folks?

But if you’re not like me, you might just be one of the three animals I’m about to list. Of all the animal kingdom’s bizarre, outlandish mechanisms, midlife sex change has got to be one of the most interesting.


Let me walk you through a scenario. You’re new at school, an all-boys academy except for one girl, Jessica. Jessica spends most her time with Brad, who is of course the most popular guy in school because, I mean, his name is “Brad.” And Brad is your classic alpha male. He chugs whey protein with egg yolks and high fives with the magnitude of a Ricther-3.0 earthquake and just invented a new genre of music called Lacrosse-Rock. Brad also has a best friend, Tim, that guy who’s a little less popular but sort of absorbs some of Brad’s coolness by standing around him a bunch.

Tragically, Jessica is eaten by a tiger shark. So now there are no girls at the school, right? Wrong! As the most dominant male, Brad naturally becomes the female. And who does he take as his new primary lover but his old second-in-command, Tim.

I just described to you what must be the especially awkward high school years of the clown fish. Clown fish live in a hierarchy with the reproducing female at the top. When that female dies, her partner becomes the new female, who then selects a mate from among the other males.


Why does this happen? Essentially, scientists say, because clown fish are lazy. They basically never leave their home sea anemone. Instead of going out, looking for new partners, a group of males can just wait long enough and one of them will swap genders. Which is all well and good, except now I can’t help but feel a little nervous every time my roommates and I stay home and play Mario Kart on a Saturday night.

Califoria Sheephead

California sheephead are a kind of fish native to the Pacific Ocean. What makes them interesting is that they are all born female. But that does not mean they won’t be able to reproduce, as anyone who has seen Jurassic Park will tell you. (They will also tell, at any given time, that we are only five years away from resurrecting a Brachiosaurus using DNA preserved in mosquitoes. As a rule, do not cite “person who has seen Jurassic Park” as a credible scientific source.)


At any rate, sheephead are born female, but most of them don’t stay that way. While it’s not clear exactly which environmental cues trigger the switch, research shows it usually happens about 2/3 of the way through the sheephead’s lifespan. That means the average sheephead couple must consist of a young, bubbly female and an older, kind of creepy and probably rich male, making them just like every other couple in Los Angeles.

Unfortunately, overfishing is taking a lot of the bigger males out of the picture. To compensate, females are turning into males sooner, at smaller sizes. Which means the remaining females are generally smaller and, as a result, are laying fewer eggs. So sheephead are dying out, and you should feel terrible. If you have any ounce of decency, you’ll go dive into the Pacific and save one right now.


Not going to happen, huh? Well, leave it to a human not to understand the complexities of maintaining sex-balance in a gender-bending society. Which leads me to my final creature…


Wait, what? This is going to need its own post. Check back later to figure out what the hell I’m talking about!

The Gay Gene: Why is it Still Around?

Some of the biggest challenges to evolutionary theory come from traits which apparently make no adaptive sense. If a feature isn’t helping an animal to survive, how does that feature survive? For example, why do people still exist who wear toe shoes outside of the gym? Certain mysteries will never be solved.

Homosexuality is a particularly interesting attribute when you’re thinking about selection. Assuming there is a genetic basis– and for the purposes of this discussion, I am– its existence is completely baffling. How can a trait persist that by definition should mean that those exhibiting it won’t reproduce? It’s the same reason I expect the dress-up-like-My-Little-Pony-characters gene to be worked out of the human race within the next 50 years. Yet homosexuality persists, not just in humans but in animals, too. It’s been shown in worms, for God’s sakes, and I’m not even sure how we know about that.


But just because there’s no obvious explanation does not mean natural selection can’t explain it. Actually, I’d say this is where the theory gets interesting. When you can’t just point to an obvious advantage of a characteristic or behavior, that’s when you have to start thinking outside the box. Here are a few ideas scientists have devised as to why “the gay” is here to stay:

Kin selection – This theory, along with many of the coming theories, is predicated on the idea that family members can carry the homosexual genes and pass them to their progeny without displaying the phenotype themselves. Now suppose that those family members actually have a better chance of raising healthy, happy kids because their gay relatives, who have no kids, are spending their time helping them. In other words, it could be beneficial, selection-wise, to have a gay brother giving you a hand at home. Not to mention he’s bound to do something about your tacky purple drapes.

Social prestige – There is some evidence that gay people have a better-than-random chance of ending up in positions of high social status. Their relatives (who, again, are carrying the homosexual genes) now have an increased chance of reproduction, because it is scientifically proven that nothing turns a woman on faster than to hear your uncle is the Eldest Shaman of Panguma.


Balanced polymorphism – Sometimes less advantageous genes are naturally paired with others which do promote survival. For example, sickle-cell disease is common in Africa because the gene causing it also prevents malaria. Likewise, gay people are immune to rabies. I made that up. But there could be, I don’t know, something else.

Sexually antagonistic selection – It is possible that a gene which works against reproduction in one sex, works for it in the other. For example, the genes which make a man homosexual might make a female carrier more sexually successful. In fact, a study has has found that “female relatives of gay men have more children than those of straight men.”

Nonadaptive byproduct – Of course, there’s always a chance that there really is nothing adaptive about homosexuality, and it’s persisted simply due to the selection of other, related traits. But this is like answering “none of the above” on a test– you better damn well rule out every other possibility first. You’d be surprised how much evolution can explain.

Four Dog Breeds with Surprising Histories

Not all kinds of selection are natural. Look no further than our grand, ongoing bastardization of the wolf. Through careful breeding, we’ve managed to produce over 400 recognized varieties of man’s best friend. And while it’s obvious what we were going for with some breeds– wiener dogs were clearly bred for us to stick them in hilarious costumes– other dog origin stories might surprise you. Here are four of the most interesting:



Possible Origins: The forbidden lovechild of the Michelin Man and a hippopotamus. A pile of lumpy pancakes coalesced and gained sentience. Somebody left their pug in the wash for too long.

Actual Origin: Those wrinkles aren’t just for storing coins and business cards, though I imagine that is one advantage of owning a Shar-Pei.

Shar-Pei are also known as “Chinese Fighting Dogs” for a reason: for all intents and purposes, these are the Pit Bulls of the East (by which I mean they were bred to attack each other, and not that they spout incoherent, Spanish phrases in the middle of Usher songs). Their loose coats mean that grabbing one by the skin can’t stop it from twisting around and lunging at you. In fact, historically, the more defined a dog’s wrinkles were in its face, the more it was considered a capable guard dog. And did I mention that those wrinkles are a Chinese sign of sovereignty? Laugh all you want at the Botox injection gone awry; next time I meet a Shar-Pei, I’ll be bowing and praying it doesn’t smother me in its kingly folds.


Possible Origins: Where Bob Ross’s afro fled to when he died. A terrible, failed early experiment in Rogaine. A drunken night between a greyhound and a Chia pet that both are trying to forget.

Actual Origin: Believe it or not, the haircut was not the brainchild of rich fashion designers with a fondness for leg warmers and too much time on their hands.

Originally, the ‘do can be traced back to the 16th or 17th century. Back then, poodles were bred as water retrievers. That’s why they’re called poodles– it’s from the German word for “splash”, which also is the root for the English word “puddle”. I’ll give you a second to mop up the slivered fragments of your mind, which has just been blown.

Shaving the poodle’s bottom half made it more buoyant in the water, while maintaining fur at the top kept it from freezing to death. Taking the hair off the face made it easier for the poodle to see its target, and the fur on the ankles prevented rheumatism. So all those poofy embellishments actually served a practical purpose at a time. Now, of course, they serve the purpose of warning us to avoid anybody who spends more money grooming their dog than paying for their kids’ educations.

Yorkshire Terrier

Possible Origins:  A young, midget Wookie was banished from Kashyyyk for being too cute. A mop was granted its wish to become a real boy. A butterfly farted on a daisy, and a dog bloomed.

Actual Origin: These guys are just your average, working-class schmoes.

It all began during the Industrial Revolution, when Scottish immigrants moved to England in search of work, taking their terriers with them. Those dogs mixed with the local Waterside terriers, giving rise to something more closely resembling the vivacious breed we recognize today. It was then that these dogs could get to doing what they do best: pulling off the hair bow with such aplomb they make Dorothy from Wizard of Oz look like Ms. Pacman. Wait, hold on– I meant hunting and killing rats in old mines and cotton mills, because that’s what they actually did. These dogs weren’t always the prissy, high-society Prima donnas which I just now decided they are. I mean, look at them.

Irish Wolfhound

Possible Origins: I’m pretty sure this is just a bear.

Actual Origin: These dogs are way more badass than bears, to the point that there is an entire website dedicated to their badassery. Let me share some of the highlights:

  • In Ireland they hunted deer, boar, and wolves so adeptly that battles were fought simply to own more of them. They eventually had to make laws limiting the number you could have, presumably because someone with over four could easily conquer and enslave a small nation.
  • It once was standard practice, before letting these hounds out at night for guard duty, to first make sure all guests were safely inside.
  • In Rome, a hound named Ailbe was so admired that his owner was offered three score hundred milch cows at once and a chariot with two horses and as much again at the end of the year” as a trade. The offer was declined.
  • In one battle, a hound was said to jump onto a chariot– causing it to collapse– then behead the driver, and kill all the horses. I’m not making this up.

Admittedly, it’s difficult to parse fact from fiction in these tales, but the fact that these hounds inspired so much legend in the first place is impressive enough. The day I see a chihuahua capable of biting off my head is the day I stop chugging 5-hour-energies and paint thinner.

The Sad Truth About Helping the Animals

And now more on why winter sucks for animals, because I pride myself in being relevant, give or take two weeks and ignoring the actual definition of “relevance.”

Conventionally, we say that animals evolve to adapt to their environments, but that’s not always entirely true. What matters is that animals adapt to the worst of their environments. Imagine a verdant field somewhere in the deepest part of the forest. Now, this place is deer-Eden most of the year. There are no natural predators. The ground is littered with buffets of fruits and flowers. There is a parking lot, packed with cars that only deer can operate, and stupid little humans run about waiting to be crushed under deer-fenders.


Imagine you are a deer and you stumble upon this place. “Finally,” you think to yourself, “here is a place I can settle down and raise my family. At last, Martha will be able to quit her job at the textile factory and focus on painting, like she’s always wanted to. Little Timothy won’t have to worry anymore about those bullies taking his lunch on the way to school. Also, I can go around rubbing my head on branches and stuff, because I am a deer, and that is what we do.”

But then, suddenly, something changes. For one week, the field is transformed into a pitiless hellscape. Flowers turn into bear traps when you touch them. Hunters assault you at every turn. Armies of wolves drive in on Humvees to play shuffleboard with your corpses. Martha is killed; little Timothy dies of starvation. You are left wounded and alone by the time the chaos ends.

The point of all this is to say: it does not matter if you can survive through the 51 weeks of paradise. Anyone can. What makes a difference, in terms of adaptation, is the deer who can make it through that final, brutal week. That’s why, after a few generations, the deer in this imaginary field aren’t going to be your average, frozen-in-the-headlights breed; they’re going to be Rambo-Terminator-deer with titanium antlers and steel hooves who don’t take none of your headlights’ sass.


Winter—yes, I was going to get back to it eventually—is the hellscape which molds most deerboys into deermen. It’s a bottleneck that keeps the weak from surviving. As I mentioned last week, the greatest challenge for deer is not the cold but the scarcity of food. They go in with well-stocked fat reserves, but they can expect to lose most of it in the following months. If those months are hard enough, many will die, especially the fawns. In fact, according to the Maine government, “Consecutive severe winters can reduce recruitment by 90 percent.” Presumably, they’re talking about general additions to the deer population, and not an underground militia that we need to start worrying about.

There’s nothing we can do about it. Okay, it might seem like there is something we can do about it (“feed the deer”), but I’m here to tell you that like most human efforts to help the environment, that’s an idea that almost definitely will go terribly, terribly wrong.

First of all, whatever you intend to feed the deer, it probably isn’t “aspen or willows.” That matters. Deer don’t digest food on their own; they have micro-organisms in their stomachs that do the work for them for certain types of vegetation. If you’re giving them hay, chances are those micro-organisms are going to react the same way you would if someone dumped hay on your plate.


Okay, say those bacteria do adjust. Now you’ve got a lot of deer coming to one place, all going after the same food source. This is the deer equivalent of a middle school boys’ locker room, in that it’s chock-full of competitive, vicious creatures and simmering with disease. The stronger deer are going to make sure the others don’t get enough—even if those others would have stood a chance on their own, in the wild—and the mass gathering of animals means disease spreads much more quickly. Soon your backyard is going to look like that scene in Monty Python where they collect the dead, except nobody’s picking up your deer carcasses.


If you do somehow manage to give the deer edible food, prevent all disease, and convince them to share, congratulations. You are going to have an overpopulation problem, and I hope you enjoy deer feeding enough to quit your day job and satisfy the droves that will show up at your doorstep next winter.

Let this be a lesson to you: usually, natural selection is the best kind of selection. So just let nature do its work.

Why We Shouldn’t Complain About the Cold

Ah, the first, true snowfall of winter—there’s something enchanting and nostalgic about it. It bears to mind thoughts of early-morning parishes around the TV-altar, awaiting Holy Word from the Superintendent, for no mere normal-intendent is He who through his divine and inscrutable methods shall Giveth snow days, or else shall Taketh Away the happiness of every grade school child in the neighborhood.


Oh, wait, it’s spring? And I’m not eight years old anymore? Then I don’t have much of a spiel for what’s going on right now, except to say it’s going to be a pain to get the car out of the driveway, and if the local superintendent does see his shadow or whatever, those damn kids better stay off my lawn. But I’m not bitter.

Seriously, though, we have very little to be bitter about. How do you think the animals are coping? (“Whoa, I did not see that segue coming!” –Someone who has never read this blog.) I mean, we all know about the ones who plan for the winter. Those swallows with their southbound migrations and their travel itineraries and their Miami Beach Wet-Plumage Contests. Or bears, who’s strategy is to carbo-load and gain thirty pounds a week before losing the weight by sleeping through the winter months—a strategy I’ve unwittingly been employing every holiday season.


But what about the other animals, the ones who can’t fly and who are too good for season-long sleeping binges? How do they get by?

The answer is, not too comfortably, but they do have their ways. Take the mule deer, a species so common in my neighborhood they’re beginning to petition for pool access. Like many dogs they grow a heavy winter coat to shield themselves from the cold. They can also “adjust the angle of their hair shafts to obtain maximum insulation,” a phrase I chose to print verbatim from the source because the writing staff of the Maine government has apparently perfected a mix of ludicrousness and vaguely dirty-sounding language that I can only hope to achieve.

Deer are known to stock up on body fat before the winter hits as well. By the beginning of the season, fat reserves may account for up to 30% of the deer’s body mass, which help insulate it further against the cold. More importantly, they’re going to need that fat to get them through the hardest part of winter—finding food.

Come back next week for a look into the brutal, hungry lives of foragers during snowfall, and a thrilling exposé on the dangers of human-run winter feeding programs (no, seriously).

Limb Regeneration is Really Cool (and Really Difficult)

Humans have come a long way in prosthetics technology. Herodotus, the ancient Greek historian, documented a prisoner who escaped his captors by sawing off his foot and replacing it with a wooden substitute, marking the first written evidence of an artificial limb, and the first of many entries in the Saw movie franchise.

These days, thanks to robotics, we’re developing some pretty amazing, Six-Million-Dollar-Man-style mechanical arms and legs. But here’s the bad news: we’re still getting our cyborg asses handed to us by the animal kingdom. And I’m not talking about worms and insects. I’m talking about salamanders. Turns out, those little guys you used to terrorize in the pond behind your uncle’s house have regenerative superpowers that make Wolverine look like… well, like someone who can’t regenerate limbs so well.

 127 hours

Here’s how it works: when a salamander loses an arm, cells near the site of the dismemberment—including those from “muscle, bone, cartilage, nerve sheath, and connective tissues”—lose their characteristic qualities and become progenitors, essentially blank slates which can be turned into any type of cell. Through a process called redifferentiation, these blank slates become the cells in a newly-formed arm. It’s the salamander equivalent of the surgeries Kim Kardashian gets to move fat from her stomach to her butt, only it occurs naturally and wouldn’t frighten small children if they showed it on Discovery.

And salamanders aren’t the only animals who could rip off the limbs and play appendage-Jenga if they wanted. Starfish, swallow-chicks, and lizards like geckos and chameleons have all demonstrated their regenerative abilities. There’s even a species of mouse that regenerates hair follicles and ear tissue. So what about humans? We’re supposed to be at the top! We can’t let lizards and amphibians and rodents get the best of us! We’re the species that saw how bats echolocate and invented radar, because screw bats!


Well, of course we’re working on it. But the prognosis isn’t good for now. The more scientists study limb regeneration in creatures like the axolotl, a kind of Mexican salamander, the more we’re realizing just how complex the process really is, which is saying a lot considering no one ever said, “Oh yeah, the Calc test? It was as easy as regrowing a leg from out of a disfigured, bloodied stump.” No one that passed the Calc test, anyway. So for now it looks like we’re just going to have to live with our limbs as they are, and maybe stay away from wood chippers for a while.