ONE of the great pleasures of science is learning how strange the world is.
This is also one of the great pleasures of the Guinness World Records and Ripley’s Believe It or Not!, however, so the American Museum of Natural History is at pains in its exhibition “Life at the Limits,” which opens on Saturday, to make clear that the show is not just about amazing species. It is about understanding how and why weird and astonishing species evolve.
But you know as soon as you enter the exhibition that its organizers have not let the seriousness of evolution, reproduction or life in dark and dank caves spoil the fun.
There, hanging above you, is a simulacrum of a tardigrade, otherwise known as a water bear or moss piglet, at about 5,000 times larger than life-size.
The tardigrade, a creature whose cuteness depends on the quality of your scanning electron microscope, is about as appealing as an organism without eyes can be. It has something on what seems to be its front end that resembles a nozzle for a sophisticated vacuum cleaner. Unlike a vacuum cleaner, the tardigrade is close to immortal. It can survive for years as a dried-out ball, with no water, and is apparently immune to radiation. It actually doesn’t look like an animal at all. In some electron micrographs, it seems to be an inflated spacesuit. Somehow, that hasn’t stopped the production of stuffed-animal tardigrades for children. The toys will never last as long as the real thing, of course, but go ahead if you are a fan of the unusual. Just don’t be seduced by the ones with eyes.
Obviously the tardigrade is qualified for inclusion in an exhibition about the forms of life that emerge at the limits — of size, environmental tolerance and reproductive habits.
Human beings, on the other hand, are an unexpected example of “life at the limits” because of our mode of reproduction. Have no fear, the limit explored here is entirely appropriate for children. Humans qualify as extreme because we usually have one child at a time and care for our children so extensively for so long, taking them to museum shows and sports camps, and shelling out astonishing amounts of money for education. No other creature known to science helps out with the cost of graduate school.
Actually, the museum doesn’t mention those details. But what else could this statement mean: “People typically have one child at a time and care for their children for many years.”
In contrast, the female Tasmanian devil, a marsupial, has 20 to 30 offspring at a time, but has only four nipples. So the little devils meet harsh reality even in the warmth of their mother’s pouch. Guess how many survive, at a maximum. Exactly. Four.
While humans win the fewest-children-at-a-time-with-longest-period-of-care contest, the ocean sunfish comes out at the other end, tops in the who-cares-let-them-sort-it-out-themselves sweepstakes. These fish lay 300 million eggs at once. Embryos — go out and play.
It’s all about evolutionary strategy. Do you put your investment in care and attention, or in sheer numbers? Both extremes work, and many in between, but it’s the ones at the limits that are most intriguing.
The exhibition features not only the wall texts that enterprising parents can read to their children — feeling immense relief that they don’t have 300 million of them — but also virtual games based on the Kinect system; a big, strong sculpted Hercules beetle for kids to climb on; videos; and a fluid, nonlinear path through the many sections, including an artificial cave.
“Life at the Limits” wears its science lightly, but there is always something to learn. Caves, for instance, are not evolutionary dead ends but prompt new kinds of evolution to cope with an environment that lacks light. And different species develop similar traits — an increased sensitivity to touch, for example.
There is something here for everyone, even for natural-history buffs who know all about the tardigrade, and how elephant seals are the deepest divers, and how the mantis shrimp packs a punch with the force of a bullet.
I didn’t know that kestrels had such exquisite eyesight in the ultraviolet range that they can see the UV reflection from the urine trails of the moles they hunt.
I had no idea that scallops had lots of eyes, or that fish that use electric organs for sensing can communicate during pack hunting — with electricity.
And speaking of electricity, I was stunned to learn that some bacteria survive not on light or chemical energy but on electricity itself.
“In laboratory tests,” the exhibition tells us, “colonies grow right on electrodes where they soak up flowing electrons.”
The show was organized by John Sparks, in the department of ichthyology, and Mark Siddall, in invertebrate zoology. Dr. Siddall said he would like visitors to come away from the show with an increased understanding of “the tenacity of life,” because, he said, “wherever it can exist, it does.”
And almost anything you can imagine it might do, it does. One of the limits explored here is how bad a smell can be. So visitors have the chance to lean over and inhale the aroma of a corpse flower.
The information presented makes quite clear that this is a stench that evolved to attract carrion flies, but you may think, how bad could it be? This is a museum exhibition, right?
Don’t smell it. Don’t even think about smelling it. Tell your children not to smell it.
If, against all parental advice, they do inhale, you can justifiably indulge in a behavior familiar to all parents when their own lives are stretched to the psychological, if not biological, limits.
You can say, as your offspring turn alarmingly green, “I told you not to smell it!”
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