Tuesday, December 10, 2013

Animals Too Weird for Evolution

Copulating hermaphrodite sea slugs soon to get violent
Sometimes the headline grabs you: "Sea Slug Sex and Violence," for example. Or, "Clever crocs, gators balance sticks on snouts to lure prey." Both are real, and both made me ask, "how in the world would these evolve?"

First, the violent sex of sea slugs. An item in the Science section of the New York Times reports, "Researchers have identified a new kind of hermaphroditic sea slug living on the Great Barrier Reef that uses its phallus to stab its partner in the forehead after copulating..." This certainly caught my attention, and I found a Scientific American article with the lead: "Everyone remember not to have sex with hermaphrodite sea slugs, because they’ll want to inject prostate gland fluid into your forehead."

Turns out biologists led by Rolanda Lange of Monash University in Australia captured 32 of the 2-4 millimeter-long Siphopteron sp. 1 sea slugs off Queensland, and videotaped sixteen couplings of their several-times-daily antics. The slugs enjoy quite a mating ritual: 2.5 minutes of twirling embrace, with a few romantic neck-bites, and some organ "everting," (the phallus turns outward or inside out). Then the sex act, and since both have male and female openings, well, one of them behaves as the male and the other, female. After that, the "penile stylus" gropes the "female", until whap! It's injecting glandular fluid deep into "her" forehead!

The experts witnessing this were flummoxed. No other animal has been observed stabbing its paramour in the forehead after coitus. They had no idea why one hermaphrodite would inject prostate fluid into the head of another one. Their speculation is that this neurologically manipulates the partner to absorb more of the sperm just received, but they honestly have no evidence for that.

Given that this weird behavior appears unique among all animals, I just wonder how and why this would confer evolutionary advantage. Apparently, the "penile stylus" is flexible enough to reach any part of the recipient; lots of other creatures poke and prod, but not the forehead. How could this fit the workings of Darwinian theory? It's possible that with enough research, we'll eventually discover why this one species of sea slug developed a behavior so different from any other creature--but for now, its habit seems illogical and amazing.

Equally astounding are the crocodiles and alligators who, only during the spring mating season of nearby-nesting birds, balance twigs on their snouts and lie motionless in the water for hours until a mama-bird, seeking nest-building material, plucks the twig and...SNAP! She's lunch!
Alligator (that's no log!) with twigs awaits lunch

Researchers observed crocodiles in Tamil Nadu, India, and alligators in four sites in Louisiana laying twigs on their barely-submerged snouts, as "tools" to snare prey. "Use of objects as hunting lures is very rare among animals," writes a team of authors led by Vladimir Dinets of the University of Tennessee. The only animals ever found with that ability are "captive capuchin monkeys, a few bird species and one insect." The big question is how the reptiles know to try their trick only in the weeks birds compete for twigs. Are they looking up and saying, "gee, I see birds swooping around, so I'm gonna camouflage myself like a log and balance some twigs on my snout"?

OK, I can't resist one more strange animal story, this one from a splashy piece in the New York Times Sunday Magazine. Rasberry Crazy Ants, named after Tom Rasberry, the exterminator who brought them to the attention of authorities in 2002, are swarming over Texas and several more Southern states. The weird part is that they congregate in electrical appliances by the thousands, and blacken dirt and pavement by their sheer density and number. When they cozy up inside a radio or TV, their little bodies complete electrical circuits, shorting out the appliance, zapping the critters, who send out a pheromone smell calling for reinforcements. By the time the owner opens the appliance, thousands of bodies, dead and alive, jam its inside.

Crazy Ants: Just 1/8 inch long, but overpowering
A June NBC News report noted, "In one case, the ants quickly spread to 90 out of 150 air-conditioning units in an apartment building in Waco, Texas," and their swarms in industrial sheds are a "problem for industries in Texas and elsewhere along the Gulf Coast." They often overtake local fire ants who bite, but at least perish with regular ant bait, which crazy ants ignore. Also called tawny ants, the crazy Nylanderia fulva drive off the much-larger fire ants; see them in a two-minute YouTube video that's had more than 91,000 views.

How did all these bizarre and mind-boggling species manage to exist and survive today? My personal reaction is found in Psalm 104, expressing the awesomeness of nature, "...How abundant are Your works, God, all of them you made with wisdom; full is the earth with Your possessions."


  1. While I am a "believer" in the Divine origins and "directedness" of the evolution of the universe, our solar system, of earth, of life on this planet, and mankind, the question still remains: Whether by Divine Direction or Random Evolution, many (most?) things in the Universe and life on Earth still don't make any sense to me -- your humble servant with a finite mind. -- steve fink

  2. Steve, if "it all" made sense, there'd be no need for scientific inquiry. The complexity and diversity among creatures and the way everything's set up is so mind-boggling and awesome that anyone who thinks about it rationally couldn't possibly believe that so many billions of "random coincidences" in evolution played out so perfectly.

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  4. The observed behaviors in these animals are devastating to the model of evolution as simply random mutation in populations over time. Particularly, the ones having to do with reproduction. Not only does each *individual* organism have to first contain the biological characteristics to reproduce with one another, but they must contain the neurological "programming" to be able to use them. They are never instructed. Moreover, instruction requires preformed knowledge. I still have never heard a scientist/researcher explain how species learn and pass along this information to their progeny.