According to Jared Diamond, in New Guinea bats hang upside-down when they sleep because after eating fruit all night, they will have to spend the next day shitting, and how they shit is through their mouths.

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Not that he believed this, of course: this was a folk belief he had been told. He taught at UCLA, knew how to tell fact from fiction. A bat has an anus in the same place you do, and your dog and your cat. Just a folk myth. It was good enough for me, though—that was exactly my kind of animal. I applied for a Fulbright, got one, and went to New Guinea. Learned the language called Tok Pisin. Found World War II wrecks in the jungle. Watched rainforest swiftlets trail strands of spider webs behind them like iridescent contrails. And yes, saw the bats, and yup, there were indeed rotting wheelbarrow loads of putrid diarrhea under the bats’ roost trees. Cause and effect. Looked fine to me.

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Interesting animals, fruit bats, in that they have a cute, dog-like muzzle and wrap their wings around their body at rest, the way Grandpa did his cape in The Munsters. In New Guinea there are 30 kinds of fruit bats, give or take, including the big five-foot wingspan ones, flying foxes. Pretty cool, all in all, to see bats as big as raptors. You know at the beach, how the gulls can hover in place over your towel and sand encampment, waiting to pluck your sandwich? How’s about a bat then that’s twice that size? Cool beans.

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Except too bad we can’t figure it out. About what they are, I mean. Kingdom, Animalia; phylum, Chordata; class, sestina or walpurgisnacht or pirouette or fugue. Species as metaphor. Maybe the bats are just varieties, like the colors of oleanders along the median strips of freeways: one species, many poisoned leaves. Ah but no, it’s a binomial thing the voice on my shoulder says. Easy and known—genus and species, separate and distinct, as in the New Guinea animal called Bulmer’s fruit bat, Aproteles bulmerae. Named after Dr. Susan Bulmer of New Zealand. Genus first, then species: always and evermore. If only.... If only.... Since, after all (I ask the voice on my shoulder), what is a species?

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Answer: well, a group of somethings that sorta live in a unit and don’t interbreed with the other somethings around them. You know, like a seagull, a seagull is a species. Well, a bunch of species. So imagine a beach in California, let’s say it’s winter in Monterey, Fisherman’s Wharf. Brisk breeze. Limpid water. Arf, arf go the sea lions, glisten glisten goes the kelp, glide-flap, glide-flap go the Herring Gulls. Larus argentatus would be their Linnaean “Hello, I’m” name tag. Others too, of course. Maybe the state bird of Utah, California Gull, Larus californicus. They saved the Mormons once by eating locusts. Mew Gulls, Glaucous-winged Gulls, Thayer’s Gulls, Ring-billed Gulls, Western Gulls of the nominate race, Larus occidentalis occidentalis. That small dark one, chocolate brown except for a dirty yellow bill, that one is a first-winter Heermann’s Gull, named for Adolphus Heermann, who in 1865 was dying of syphilis of the brain when he shot himself by accident while hunting, though not before coining the word oology, the study of eggs.

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So many species, so little time.

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One reason apprentice birders take a while to learn their gulls is that it’s not just the residents and not just the über rare ones that drift over from Siberia just to mix things up, like a sentence of Russian inserted into the middle of your Latin exam, but it’s that we have the whack jobs too. Hybrid gulls really throw field guides into the blender. I have before me a recent and magisterial 500-page book on the gulls of Americas, written by Dunn and Howell, which is like owning a book on transcendentalism edited by Emerson and Thoreau. (Steve Howell even looks a bit like Thoreau.) This treatise investigates 36 different gull species, some of which have up to eight plumage cycles. 8 x 36, that’s not so bad, no harder than conjugating Anglo-Saxon, but then there are the variants that may well be species, so that’s another 8 forms / types / species, so that brings it up to 44 gull thingies in the Americas, not counting the Eurotrash strays that turn up once a decade. Ah, but what about hybrids?

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The authors take a running leap at it. They itemize another 14 aberrancies. Not species, but things well enough known to merit their own write-ups. There is the American form of Herring Gull (maybe a species, maybe not) crossed with Great Black-backed Gull. There is American Herring Gull crossed with South American Kelp Gull. There is the European race or form or species of Herring Gull crossed with Lesser Black-backed Gull. Anybody got a score card? It’s a larid orgy. But then there’s the potential of the hybrid cross-pollinating back into the main herd. Not supposed to happen, but then in some colonies, according to the ornithology experts, up to 75% of the progeny of a given year are hybrids. Hey now. What about the boundaries of what keeps one species separate from another? Up and down the Western seacoast, from Baja to Alaska, we have the species intergrading clinally. Western Gulls hybridize with Glaucous-winged Gulls, and then the Glaucous-winged Gulls hybridize with the ones just to their north, the Glaucous Gulls.  It’s as if the Jell-O hasn’t quite set, and their species-ness keeps slopping out of the mold.

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Okay, smarty pants, says the voice. Forget birds. Try a tree. A tree can’t sneak off up the beach, misegenate with the marsa’s wife. Trees are like ents: deliberate and solid. Yet can we even know a tree? As visually trained primates, we look for the wrong things, like the color and shape of the leaves. David Sibley (who is Nathaniel Hawthorne to Dunn and Howell’s Emerson and Thoreau) says about trees that they don’t really care what other trees look like. They care maybe about sap, maybe about pollen, maybe about when the other oaks are masting acorns, but not about whose foliage is green as Easter grass. Color and shape mean nothing to them. Meanwhile, some plants are asexual, so that messes with our breeding population definitions, and of those that are not, what about hybrids? Tons of those in any forest. And a subspecies, to pick even smaller nits, is not the same as a cultivar, and that’s different from a mere variant. Sibley throws up his hands: “There is no consensus [about what is a species], and in fact, multiple criteria are probably needed.”

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The basic species definitions all fall apart. Let me skip about 10,000 words of summary of each type of alternate definition of species, let me skip the late, great master of the phylogenic species concept Ernst Mayr of Harvard, and let me skip too things like lichen (half fungus, half algae, half commune, half question mark). We’ll skip viruses and fruit flies and convergent molecular evolution and allopolyploidy and my lyrical descriptions of Band-tailed Gull, Larus belcheri, added to the official bird list of Ecuador via a sighting written up by the artist Bruce Bartrug and myself.

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Skipping all that, it comes down to this: “species,” that primary building block of biology textbooks, ecological law, and Audubon Society calendars, is just fog in the spruce. It doesn’t exist. It’s ain’t real. All it is, is a metaphor. As a culture, we need it, just as we need sonnets and the 23rd Psalm and John Cage’s 4’33”, but it’s only a place marker for something we can’t define, can’t prove. The term means “some species-like unit whose boundaries we are not quite sure of; see ‘poetry’ or ‘love’ or ‘intelligence.’”

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Pretty clever of us to think up species, as an idea. Too bad we usually do so badly at being a good species ourselves. Even the fruit bats hate us. Here’s this, from Wikipedia: “Bulmer's fruit bat was first described from 12,000 year-old fossils found in the central highlands in Chimbu Province, Papua New Guinea. It may have become extinct there about 9000 years ago. In 1975, it was discovered in the Hindenburg Wall area of Western Province, Papua New Guinea, in a cave known as Luplupwintem. At that time, local inhabitants described it as abundant, perhaps numbering thousands of bats. However, two years later, the colony had been decimated, apparently by hunters who entered the cave with shotguns and store-bought ropes. During the 1980s, no bats were seen and it was feared that the species may have become extinct. However, by 1993 a colony of about 160 bats was known to be living in the same cave.”

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Well now, go us. Right on for Team Science. After looking and looking, we found 160 of the missing bats. (The finders were probably crushing an endemic species of fern as they stood in the underbrush, peering up at the cave mouth with flashlights, looking for the bats.) It reminds me of sea otters of Monterey: the Russians came to coastal California, killed them all, then left, satisfied with a job well done. Sure, they had to kill them: just stroke that fur— a million trillion guard hairs per square inch or whatever the stats are. Ain’t no better pelt anywhere. Mink is like burlap compared to sea otter fur. So Russians came, Russians went. Luckily they don’t have a very puritanical work ethic and so missed a few, missed a few rogue anti-social sea otters hanging around fugitive coves at Big Sur. It’s from that relict population that the cute little tourist industry money-makers all descend from today.

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What is a species? A metaphor, a phylogenic clade, an answer on a quiz.

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How many species are there in the world?

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Two: the human species, and all the rest, who are hiding in the kelp until they think that we’ve finally gone home.

 

 

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