You’ll be pleased to find out that I just purchased twenty ghost shrimp on EBay. I thought the loach had eaten the previous herd of ten, but I was delighted to discover there were survivors. So now I’m getting a bunch more, figuring the loach will take his share but the rest will be around to partake in the great fish dying due anytime now, as the vast herd of platys reaches their life expectancy and bloops their last bloop. Some fish corpses float, some sink. The floaters I scoop up with the net and toss into the planter out front. No point in wasting good fertilizer. The sinkers are a pain in the ass. So the shrimp get those. They can reduce a fish carcass to nothing in a matter of days. I’d rather not think about it. And the platys own culinary kinks guarantee the population will not recover, because a platy’s favorite dish is fresh born platy. None of the babies survive the feasts, and as there is no longer a dense jungle of floating vegetation for the fry to hide in—they ate that too, for roughage I guess—the babies are easy pickings. You can see the adults gathering together and leisurely devouring platy DNA. It’s fucked up. But it did neatly stop the aquarium’s population explosion, and there was one baby, as in a single fish, that has made it to adulthood in the past year. They’re efficient, you gotta give them that. So efficient they’re eating themselves into extinction in our tank. Platys live three to four years, typically, but invariably fish in our tank live to the outer edge of their life expectancy, so I won’t be surprised to see many of them last for five. But eventually the lot of them, nearly all of which born in a single year, will go to fish heaven, leaving all sorts of niches for us to fill with species that don’t fuck so goddamn much. Some fish have no shame at all.
A plastic baby platypus:
A real baby platypus:
Now you know.
Blue Planet 2. Problem solving and coordinated group action by clownfish. Who knew? Besides other clownfish, I mean. And what’s with the meter long carnivorous worm? Teeth sharp as pinking shears, hence the name: Bobbitt. As in Lorena. David Attenborough left that part out (no pun intended).The damn things can get up to ten feet, I read, like sandworms in Dune. They can lop a foot long fish clean in half. A Devonian Era nightmare, giant meat eating invertebrates. Acid visions of carnivorous trilobites. Thankfully they went instinct first.
Then the scene with hundreds of reef sharks swimming menacingly above thousands of groupers. Suddenly l’amour drives the groupers mad and they rush upward into the sharks, shedding eggs and milt to the seven seas. The sharks go into a feeding frenzy and the surging waters are all blood and roe and sperm, a veritable fish fuck massacre. Stella!
The clownfish were so neat and orderly and mannered in comparison. They’ll go far. Check back in a hundred million years.
(Originally posted on BricksScience.com in 2018).
1968, it says on the back in my mother’s flawless longhand, Age 11. I was probably 5’6” by then. I was 5’5” earlier in 5th grade, which I remember since the kids said I was fifty foot five. I peaked out at 6’5” when I was sixteen, so I was gaining height about two inches a year. Must have spent a lot of time waiting for a flood. Adolescence had trouble keeping up and I was coming in on six feet before my voice finally cracked in 9th grade. I had the voice I have now by the time I was a sophomore. I remember all the songs I could sing just a few months before were hopelessly above my range. No more Simon and Garfunkel for me, Emily would have to find herself. Not that it bothered me any, because suddenly my voice had power, and no one ever fucked with me. It was like being a grown up in 10th grade surrounded by all these silly kids. That’s a very easy way to begin adulthood, everybody thinking you’re somebody because you’re so goddamn tall, everyone seeking your approval, dudes apologizing who hadn’t done a damn thing to apologize for but just wanted to be safe. But then that’s a behavior that’s been hardwired into us apes—gorillas, chimps and all the various human species—since we evolved from monkeys 25 million years ago. I’m just carrying on the tradition.
Damn, man, got an overpopulation crisis in the aquarium. Platys up the wazoo. They’ve live bearers—as opposed to egg layers—and being really awful parents they tend to devour their own offspring. You can see them hunt them down, moms and dads and extended family members all in an orgy of devouring their own genes, evolution be damned. Of course, this keeps the population in check. Now in the wilds of Central America the newly born hide amongst the vegetation. In your typical aquarium with its handful of plastic plants that is not much of an option and the entire litter (or whatever a bunch of fry is called) is lunch. Alas, our tank is positively lush with plants, real plants, unplastic. So a mess of the little fuckers made it. And now they’re adults, beautiful, happy, healthy adults. On the handy side they’re amazing algae eaters, better even than the impossible to spell otocinclus. And they don’t make a lot of noise. Or pick on the other fish. The tank looks like a freshwater tropical reef, plants and fish everywhere. Have no idea what to do. Maybe consider them an investment, being that they’re running four bucks each in the shops now so eventually we can retire. But we’re already retired. They’re too small for a Friday Night Fish Fry, and too big to put down the garbage disposal without years of analysis. If anyone has a fish tank that could use a few of them, you can have as many as you want. It’s an incredibly healthy aquarium—we haven’t had any fish diseases since the 80’s, three tanks ago. Our damn fish live forever.
In the meantime I’ll sit here and watch them swimming and blooping and chasing each other and think about life. There sure is a lot of it in this fish tank. Damn. And you thought you had problems.
“Female termites in Japan are reproducing without males” – Newsweek
Parthenogenesis. Fairly common among the social insects. It’s cloning. Upside is that it avoids sexual reproduction, which takes up considerable resources and requires otherwise useless males like yours truly. Downside is that eventually something comes up that your hardwired DNA can’t handle. You’ve parthogenetically opted your DNA out of natural selection. Extinction looms. Which is what happens when selfish genes are way too selfish. Hence most species have sex instead of cloning around.
I suspect that the exponential increase in the pet cat population led to the exponential increase in urban and suburban coyotes which led to the decrease in the time cats spend outdoors which has caused the exponential increase in the urban and suburban brown rat population which has caused an increase in the amount of rat poison used which has dramatically increased the number of dead and dying rats which has led to the increased mortality in owls I read about today.
Weird how cultural perceptions change over time. When I was a kid, axolotls were really freaky looking, almost science fiction, even scary, like aliens. As bizarre looking a creature as you could find in earth. Even the name, a Nahuatl word (they are found in lakes around Mexico City), meant water monster. A little foot long water monster, pink (a relatively rare color in the wild, they are typically brownish) and exotic and weird, especially with those bizarre juvenile gills retained in adulthood. Now in this adorable educational video, fifty years later, they are seen as positively cute. They look cute to me even. How can anyone not love that anthropomorphized smile? Ripley (distinctly not a Nahuatl word for water monster) seems to have a personality, like an anime character (though in Japan, where giant salamanders are five feet long and without the neotenic gills, salamanders are more unnerving than cute and even show up in a Godzilla movie). Somewhere over this past half century there’s been a fundamental shift in what is freakish and what is cute, a shift that even changed my own perceptions. Who knows how this works. Collective thinking. We are still far from a full understanding of how our brains work, and just beginning to figure out how all our brains work together. We stumble through existence with this unparalleled device in our heads, clueless, almost, as to what it is making us think and see and do and remember.
Our zebra danios have gotten scary. Where once they’d dash about madly at the top of the tank waiting for the flakes of food, now they wake slowly from sleep, huddled together, then in a three fish column begin moving slowly (not their usual frantic dash) into the plants, moving around them, seeking meat. The flakes of fish food float down all around them but they pay no attention. They keep prowling, methodically, maybe an inch or two from the bottom of the tank. I’ve come to suspect that this was how they killed the other fish, by catching them before they were completely awake there amid the plants. I can only imagine that all three would rush in, striking, chomping, killing. In the wild they eat insects and crustaceans and worms, so they are hunters, yet in the thirty some years we’ve been stocking our aquariums with them I have never witnessed them do anything more than grab flakes of fish food drifting by. I have certainly never seen this sort of apparently coordinated behavior. It seems that almost every vertebrate has within it the predatory behavior. We are all hunters. Hell, it was predation that drove evolution itself, the whole Cambrian Explosion with all its crazy speciation was the result of the ever evolving contest between predator and prey. And here, somehow, in our little aquarium, something turned these little inch and half long fish from eaters of fish food to eaters of fish, eaters of even their own kind (as there were five of them just two weeks ago). All was peaceful until the clown loach died. That loach, though never deliberately bothering any of the other fish, was at seven inches long to them like a whale shark is to us. It ruled the floor, digging up snails. The danios stayed up several inches in the tank, away from its sudden movements. But then the loach, one day two or three weeks ago, was dead. Old age. I noticed the next morning that the danios were down zipping around at the bottom of the tank. The neon tetras calmly minded their own business, the two glass catfish scooted about. Everyone, danios included, got very excited at feeding time, like they always did. Everyone swam around excitedly, grabbing bits of tetra min flakes floating by.
I’m not sure when exactly the danios turned into killers. Within two weeks I realized that all the fish were gone but these three zebra danios. Alone in the tank, they chased each other madly about, zipping one way, then another. I was mystified. Where had all the other fish gone? I did some research, and found desperate pleas on aquarium websites. “Help, my zebra danios are eating each other!!!!” or “My zebra danios are killing my other fish!!!” I read in shock just how murderous the little beasts can be. No one seemed to know why, but there was usually a dominant fish that sets it off. A handy bit of evolution, that, where some members of the species will suddenly go rogue, turn alpha, and eat everything piscene in sight. Obviously there is a genetic advantage in there somehow. Perhaps a surge in zebra danio testosterone. But I have no idea. Looking at the tank again, one of the danios is swimming like a lunatic now, frenzied. The other two have ducked behind the leaves. Perhaps there is murder afoot.
Nice bit of convergent evolution on display here when you compare this shark with the fish that evolved into all us four-limbed landlubbing tetrapods. Our own fish ancestors, though, were lobed finned with bone skeletons (like coelacanths, or an even better example, lungfish). Mudskippers, a walking ray-finned fish, are another bony fish though unlike either early tetrapods or this epaulette shark, it uses only its pectoral fins and not the pectoral and pelvic fins. Mudskippers pull themselves around by their front limbs. Tetrapods and epaulette sharks walk. Or proto-walk. They use all four limbs. Watching this little epaulette shark is eerily like watching a monitor lizard. It’s hard to think of anything strictly terrestrial that moves like a mudskipper. Yet it is conjectured that most early tetrapods like Tiktaalik lived much like mudskippers, and not much like this epaulette shark. Go further back a few million years into tetrapod evolutionary history and you can find lobed fish, such as Panderichthys, that probably lived lives much like our walking shark. Unlike mudskippers and we tetrapods, however, sharks are famously boneless. They leave lousy fossils, mostly teeth. Some really terrifying teeth, too. Megalodon has left its thirteen inch incisors scattered in fossil beds world wide.
But this shark here is maybe three feet long and quite harmless, and I watch and rewatch him perambulating across the Coral Sea floor cartilaginously, a nifty trick, but severely limiting if one is thinking about evolving into a land animal. Without the buoyancy of water, one needs the support of a bony skeleton. Gravity is a bitch. But one also needs a bony skeleton to evolve fins into limbs that all of us tetrapods use for legs, arms, feet, hands, fingers, toes, and wings (and sometimes back into fins). The jointedness of bones seems to open up a wide range of mutation possibilities–and evolution is all about mutations–that cartilage just does not seem to have. Sharks and us have been on dramatically divergent evolutionary paths since we last shared a common ancestor well over four hundred million years ago. And shark evolution, though impressive enough in its sleekness, is vastly less varied than that of those of us who spring from the homelier lobed finned fishes (and less varied than the bony ray-finned fishes, which make up well over 99% of all fish species but never left the water). Aside from our perambulating friend here, all sharks (and their cousins, the rays) swim, while nearly all of the tetrapods (i.e., four limbed creatures who live on land) walk. But the same mutational capacity that enabled the first tetrapods’ pectoral and pelvic fins to evolve into a dizzying variety of limbs continues to enable tetrapods to evolve amazing adaptations with their limbs. Vertebrate flight has evolved three times (pterosaurs, birds, bats) while frogs and kangaroos hop and snakes and legless lizards slither limblessly. There are lizards and a number of mammals who glide. Pangolins go totally post-tetrapodal and curl up into an armored ball and hurl themselves down hillsides (the sort of thing that does not show up in cladistics.) A few tetrapods have even gone back to the ocean for good to swim again, the front limbs evolving again to pectoral fins, the backs legs disappearing entirely, as if four hundred million years of terrestrial evolution had all been some terrible mistake.
Yet the simple advantages of walking along rather than swimming over a shallow sea bottom (watch the video at about 25 seconds when the shark stops to peer into a cavity, looking or smelling for possible prey) apparently led this shark along a trail of mutation that eventually allows the thing to walk with ease. And it is extremely unusual for a shark. The range of design among sharks and rays is very minimal. Very few sharks don’t look very similar to other sharks. Rays look like rays. A Greenland shark is notorious for being so old and creepy and strange looking. But it looks very similar to almost all other sharks. An aquarium with nothing but sharks would be a pretty dull looking aquarium. They look a lot alike, they act a lot alike. Then we see a video of a epaulette shark walking along the ocean floor like it’s the most natural thing in the world.
A prowler of tidal zones, an epaulette shark can survive for hours in extremely low oxygen pools. It cannot breathe air, though, as mudskippers and lungfish do and our own water’s edge ancestors once did. Rather this shark has evolved a way to reduce blood flow in critical periods to all but the brain and heart. Handy, but a no go as a terrestrial adaptation. One needs to breathe air to make it on land. So this remarkable shark is no more like us than we are like it. It’s a marine animal who sometimes can stay on the edge of land for a couple hours, just as we are terrestrial animals who sometimes can swim with the fish for short periods.
But it was the combination of using fins to lift and carry across surfaces (i.e., walking) where swimming was difficult or impossible, with getting oxygen from the air via lungs (i.e., breathing) instead of taking oxygen from the water via gills, that made vertebrate land animals possible. (Insects were already there–doubtless tetrapods were eating them–but they had evolved from marine invertebrates, and our last common ancestor was somewhere deep in the Pre-Cambrian). There are over 30,000 species of tetrapods today–7,500 amphibian, 10,000 reptile, 10,000 bird and over 5,500 mammal species–and all remarkably seem to have come from one species of lobed finned fish that managed to combine both fin walking and air breathing, and had an unusual capacity for mutation in pectoral and pelvic fins. There was a wide range of these mutated fins at first–as many as eight digits on each fin–before the final five toes/fingers was arrived at. (Perhaps the occasional six toed kitten or baby are a mutational echo of that.) There seem to have been many species that could do so and apparently the lush and swampy Devonian shore line was rich enough in food and varied enough in niches a half billion years ago to allow evolution to run riot. But apparently only one of those species led to all the four footed or two footed and two armed or winged creatures breathing air today, including us. And while this beautiful little epaulette shark has nothing to do with any of our own evolution since the Devonian, as it is only very distantly related to any of us tetrapods, watching it trundle across the ocean floor does give a brief glimpse of what our own origins looked like nearly half a billion years ago.