Does that sound like the name of a hardcore metal grrrl band to anyone else? No? Well, when I tell you that there are multiple species of lizard in Mexico and the US Southwest that are all female and that no male members of these species exist, I am not kidding (nor am I writing a science fiction novel). It’s a real thing, kids. A species of animal that needs only one sex to reproduce is called parthenogenetic, and surprisingly, it happens in over 70 species of vertebrates. Some species of snail, some pythons, hammerhead sharks and Komodo dragons are parthenogenetic (or will occasionally revert to parthenogenesis, depending on the circumstances). Also, just as a fun fact, the name itself comes from the Greek words parthenos or “virgin” and genesis or “creation”.
Parthenogenesis usually evolves in species that are extremely isolated–from other groups of similar organisms, from members of the opposite sex, or both. These lizards, hanging out in the baking deserts on the border between North and South America, fit the bill. Until recently, scientists were stumped as to how these lizards could produce fully formed offspring: in ‘normal’ sexual reproduction, the female contributes half the chromosomes in her egg while the male donates the other half through his sperm, and the two mix in different creative ways to generate genetic diversity within the population (not that DNA can get ‘creative’ per se, but you get my drift). So if there are no males involved in this process, how are the offspring getting the full complement of genes? As it turns out, the mother provides both sets of chromosomes all on her own.
These resourceful mamas start out the reproductive process with eggs that have twice the number of chromosomes as sexually reproducing females, meaning their offspring will be genetically identical, excluding the random mutation that is bound to occur. They also undergo some pretty fab-tastic genetic recombination with sister chromosomes to make sure the genes stay heterozygous. Although their method of reproduction can decrease the genetic diversity of the population and thus make the individuals more susceptible to disease and predation, it also means that a single lizard could explore and inhabit a new territory and populate it all on her own! (Think about how handy this would be if you were the only woman standing after the zombie apocalypse…)
Even though these lady lizards do not need a male partner to fertilize their eggs, (got it covered, bro, thanks!) they still need to engage in a copulatory act. This means that two female lizards, even though neither can (or needs to) fertilize the other, will perform the movements of traditional copulation. This sends the trigger to their brains that allows them to lay their eggs. The fact that mamas still need faux-copulation as a mechanism to signal egg-laying indicates that males were once an essential part of the species, and though the male population has been lost, the copulation trigger has been conserved as what animal behaviorists call a ‘fixed action pattern’ within the species. (below, two lady lizards helping each other out).
The BBC, as always, has some pretty awesome videos on the subject of parthenogenesis, as well as some commentary on the whiptail lizards themselves, so check it out! Revel in the fact that there are species on Earth that will produce countless virgin births in the years to come–someone tell the Pope.
(I’m gonna call y’all dudes because anybody who reads about science is a dude. Guys, chicks, your dog, your grandmother, everyone. Everyone is a dude).
Let me tell you about thing that you should read. It’s called Spillover,by David Quammen. First of all, don’t let the cover deceive you—this book is not terrifying. Well, at least, not in a ‘man-eating baboon apocalypse’ kind of way. More in the ‘there are diseases everywhere and they kill you by eating you from the inside-out’ kind of way. So slightly terrifying. But mostly just really fascinating and cool.
David Quammen, just for your own edification, is awesome. He was a Rhodes Scholar who graduated from Yale and then did his postgrad at Oxford. He’s written an overwhelming of columns and articles about nature, travel, and adventure-y type things, as well as 15 books. That’s right, 15. 5 of which are fiction and the other ten of which are about wicked cool science stuff. Like Song of the Dodo, which is above all, an amazing title for a book, and also an in depth look at why island ecosystems are so susceptible to extinction and how humans contribute to that process.
Spillover is his latest book and is actually what has inspired me to be a science writer (lemme tell you why). In this work, he explores the vast concept of zoonotic diseases, or diseases that are transmissible from animals to humans. I admit, it sounds pretty gross and scary, but Quammen’s focus on the personal lives of both the human researchers and the oddly relatable life-cycle of the diseases makes his coverage of a potentially gruesome subject much more palatable and, well, personal.
He takes separate outbreaks of diseases (both viral and bacterial) and groups them into families based on similarity; of discovery, of treatment, of geographical proximity, of life cycle. These diseases become intertwined in a narrative that is more gripping than horrifying. It addresses outbreaks or diseases that you’ve vaguely heard about—on the news or in pamphlets at the doctor’s office—and makes them understandable and relatable. Even before you’ve realized it, Quammen has taken something biologically, ecologically, and sociologically complex, broken it down with a healthy dose of anecdote and snark, and suddenly you understand with perfect clarity the intricacies of the Hanta virus.
In general, Quammen is one of those writers who makes you want to be whatever he writes about. He writes about ecological diversity, you want to be a conservation biologist. He writes about disease transmission, you want to be a virologist. He writes about The Reluctant Mr. Darwin, you want to be a biographer and historian. After being taken on all these fantastic rides by Mr. Quammen, I figured I’d just cut to the chase and become a writer like him. That way, I get to be all of them.
Boobies live off the western coasts of Central and South America. The name ‘boobies’ is thought to come from the word ‘bobo’, which is Spanish for stupid. Probably because the Spanish explorers had some laughs about how clumsy, awkward, and completely unwary of humans (see ridiculous ‘I do-not-give-a-crap’ expression above) these birds are. Plus the blue feet. They’re like the birthday clowns of the bird world.
The blue feet are used during the mating rituals of these crazies—the better the male’s blue coloring, the more the female wants to get it onnnn. This is because the blue color comes from carotenoid pigments the male ingests through his diet, mainly antioxidants and immune boosters. That means that the more blue, the healthier the bird, and also demonstrates that he’s a capable food-gatherer. A booby with really blue feet is like a man wearing a sign that says ‘I am super fit and can provide for myself and others, come have sex with me’. For real.
The feet are also so big and weird-looking because they can be used to cover, protect, and warm the eggs. Like little blue egg-umbrellas.