Tag Archives: mammals

Double or Nothing

Nine out of ten Earthlings agree: Nothing beats a hot pair of twins. If you are already attracted to someone, the only thing that can possibly improve their overall hotness is discovering that there is two of them. In fact, that’s the best theory I’ve heard yet to describe why identical twins, as a phenomenon, are so popular in everything from DoubleMint Gum commercials to Playboy spreads: we singletons tend to objectify them as the same person with the advantage of having two bodies. But biologically speaking, does having a clone confer any advantage to you as an individual, or even to you as a species?

There are some questions better left unasked.

First, a primer on twinning. Dizygotic twins, otherwise known as fraternal — or, in the case of two females, which is more common, sororal — twins are the product of two separate eggs, and form in two separate placentas. In humans, having any kind of twin is a gamble — even a fraternal twin is five to seven times more likely to die in the womb than a singleton fetus, and at much higher risk of mental retardation, learning disabilities, respiratory problems, cerebral palsy, and a host of other health problems. But in the animal world, di- or polyzygotic young are the norm; we call them litters. In a cruel world, a species usually cannot count on only children to further itself, and so hedges its bets with siblings.

With dizygotic twins, it is possible to produce siblings with different genetic defects.

More rare in humans and other animals are monozygotic twins; that is, identical twins developed from a single egg and placenta. You might be a twin or know a twin who looks very different from his or her womb-mate, as environmental factors such as lifestyle choices and childhood illnesses cause certain genes to express themselves in one twin and not another. Identical twins may share the same DNA, but don’t bear the same fingerprints. I’m a singleton myself, but sometimes I imagine a hypothetical twin brother I might have had who works out, is a vegetarian, and hasn’t been drinking coffee daily since age 14. He is 6’1″, physically fit, has a normal haircut, and I secretly hate his guts.

Happy as he was for his brother Paul, Morgan Hamm had to wonder if he took the silver medal because he had eaten a second slice of birthday cake at age 9.

Twins in human reproduction seem to be a happy accident; after all, twins make up a mere 2% of the world’s population, with identical twins or triplets constituting only 8 percent of those, or 0.2% of all people. But what about species in which twinnage is fairly common? Can producing two or more genetically identical offspring be a successful reproductive strategy? At first glance, the animals that frequently have twins have little in common: ferrets, cats, sheep and deer all frequently bear twins, and polar bears almost exclusively do. But for popping out passels of identical bundles of joy, one mammal has the rest beat: the nine-banded armadillo, which as a rule produces litters of identical quadruplets.

Nothing beats a hot pair of twins, except two hot pairs of twins.

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Radioactive

The world is watching in horror as Japan begins to suffer the effects of massive radiation poisoning following the earthquake’s destruction of several nuclear reactors. Our primary concerns right now are for the beleaguered people of Japan as they struggle to survive and contain this catastrophe. But once the immediate threat has passed, as we all pray it will, the question that must be answered is no less important, as it is far further-reaching: What will the impact of the irradiated sites be on the environment? And what effect will nuclear radiation have on the local wildlife?

First, a primer on radioactive decay for those who are neither science-minded nor paranoid survivalists with their own Spam collection. Radioactivity is the release of particles from the nucleus of an atom as it loses energy. We receive most of our Daily Recommended Value of radiation directly from the sun, or from the Earth, primarily as radon gas. We are constantly bombarded with cosmic radiation. It’s what mutates our genes and moves evolution forward, and also gives you a wicked tan. In fact, it’s all we can do to shield ourselves from normal levels of radiation, so the particles streaming from decaying atoms of a heavy isotope of uranium or plutonium are especially dangerous. Alpha particles — bundles of two protons and two neutrons shooting from the nucleus as the atom decays — are relatively harmless, as they’re too slow to penetrate the skin. Beta particles, which are electrons, are a hundred times faster, but are too small to penetrate skin. But ingest an element that’s shedding these particles, and they will bounce around in your cells like ricocheting bullets, destroying all the DNA in their path. And as far as radiation that can penetrate your skin, like electromagnetic gamma rays, I think we all know what happens when you play with that stuff.

Overly ponderous yet ultimately respectable Ang Lee movies?

If, like me, your first exposure to the concept of radioactivity comes from comic books, let’s set the record straight. While radiation can be used to do things like destroy cancer, rumors of its magical healing properties have been greatly exaggerated. My favorite example is the radium-laced “tonic water” jars that were briefly popular in the beginning of the 20th century, according to the belief that drinking irradiated water gave you vim and vigor. American industrialist tycoon Eben Byers was a promoter of this revivifying elixir, and had a bottle every day. When he died in 1932, the Wall Street Journal headline read, “The Radium Water Worked Fine Until His Jaw Came Off.” Having ingested more than three times the usual lethal dose of radiation over the course of his lifetime, he was buried in a lead-lined coffin.

Some preferred to take all their nuclear radiation in one big dose.

And there is the sad truth about radiation. Subject an iguana to radioactivity, and it doesn’t grow into Godzilla; it just pukes and dies. A bite from a radioactive spider is less likely to give you spider-like powers than it is to endow you with a superhuman inability to bear children. Coat turtles in radioactive goo, and they don’t turn into ninjas. They just get cancer.

Godzilla: Not Realistic.

So what might happen to the irradiated animals of Japan? To get a glimpse into the potential danger of radioactive wildlife, we don’t need to consult science fiction stories or comic books. We just need to examine the results of the 1986 Chernobyl disaster and its legacy, including terrifying and true story of the packs of radioactive wild boars causing havoc in Germany today.

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Dog Whistles & Subwoofers

Last Friday’s horrific earthquake and tsunami in Japan got me thinking about the last major tsunami in memory, the cataclysmic Indian Ocean tsunami of 2004. Much was made of the fact that, though entire towns were leveled by the flood, very few wild animals perished. It seems that about eight hours before the tsunami hit the shore, there was a massive migration of animals to higher ground. What tipped them off? The infrasonic sound of the approaching wave rumbling under their feet. And when I think of infrasound, the first animal I think of is the giraffe.

Really? I don't remember saying anything.

Why the giraffe? Why not a well-known basso profundo like the elephant? I have written about giraffes before, mainly in the context of how incredibly gay they are. But I’ve never written about their songs.

It was thought for centuries that giraffes were practically mute. Like rabbits, they were only known to make sounds in times of distress or courtship: whinnies, bleats, snorts, coughs, and even the occasional groan, mew, or bellow. But it was presumed that, for the most part, giraffes were simply very tall wallflowers. Then, in 1998, a bioacoustician named Elizabeth von Muggenthaler borrowed some high-tech equipment and discovered that giraffes are actually extremely talkative. They’re simply having a conversation below our range of hearing.

That giraffes are basses should have been obvious from the necks.

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Baby Fat

So, how badly do you wish you could have just slept through this entire winter? There are many ways to hibernate, but one style of hibernation stands out as especially advantageous. You never wake up, you give birth while you’re asleep, and perhaps best of all, you lose your body fat without losing your muscle. Imagine being able to eat as much as you want, go to sleep, and wake up ripped. There are only two animals we know of that can burn significant amounts of fat without losing muscle mass. One is a baby. The other, a bear.

Which is basically a baby.

It is hotly debated by experts whether what bears do can be called hibernation. After reviewing the evidence, I stand with those who say it is. It’s simply a hibernation for the big-boned fellas. See, the little guys, like chipmunks, hibernate by lowering their body temperature dramatically. A bat, for example, can lower its body temperature almost to the freezing point. But they keep a food store handy, and every few days they heat up and wake up to eat and defecate before falling back into torpor. A bear, on the other hand, slows its metabolism a great deal, but doesn’t chill its body temperature appreciably. So if you were spooned by a sleeping grizzly, you’d still be nice and toasty, if a little unsafe. What’s more, though a bear can go from being a deeply unconscious heap of fur to 700 lbs of bitchy fury in about 30 seconds when disturbed — again, spoon carefully — it can go up to seven and a half months without waking up once. It recycles its urine for hydration, and is the only animal known to be able to transform urea — the yellow, poisonous part of urine which must be excreted from the body — back into valuable protein. As for defecation, the bear creates a dense “fecal plug” of intestinal secretions and dried poop that corks up the bunghole to prevent any “accidents.”

I've been asleep since November, I haven't eaten or shitted for five months, I woke up with two kids I don't remember having, and I haven't had my coffee yet.

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Pseudocidal Tendencies

If you want to know how to fake your own death, you have many exemplary mentors to choose from: Andy Kaufman. Tupac Shakur. Elvis Presley. Jesus Christ. Ol’ Dirty Bastard. The art of pseudocide is a revered tradition throughout human history. The most popular way to fake death is by drowning, as it eliminates the need to provide a body, though the 9/11 attacks also provided a convenient excuse for escape artists to vanish into thin air. The motives for pseudocide are many: most folks who fake death are evading the law, but there’s always the ever-popular publicity stunt, or fraudulent collection of life insurance. Ken Kesey, author of One Flew Over the Cuckoo’s Nest, faked his death and fled to Paraguay in 1966 to avoid jail time for possession of marijuana. “Lord” Timothy Dexter, a New England businessman and famous kook, faked his death in the early 1800’s just to see how people would react. (His wife refused to cry at his funeral, for which he later caned her.) Connie Franklin faked his death by homicide in 1929. Later that year, the “Arkansas Ghost” was discovered in a nearby county and was brought to court to testify at his own murder trial.

Elvis Presley: Currently 75 years old, a Walmart greeter in Boca Raton, and 500 lbs.

But pseudocide isn’t just a lame plot device or a conspiracy theory for fans who can’t cope with a celebrity death. (I know you’re reading this, Stephen Jay Gould!) Animals use the tactic of faking their deaths to get out of a pinch, just as humans do. You know it by its more common name: playing possum.

The larval stage of the Virginia Opossum, before it metamorphoses into its final "roadkill" phase.

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Zoopharmacognosy

If you’re an orthodontist looking for a new challenge, I recommend you look no further than the dental disaster that is the babirusa. Beauticians, I extend the same chance to prove your skills. Whether it’s a form of wild pig, which it’s currently classified as, or some sort of pig-deer, as its Malaysian name suggests, or is actually a distant relative of the hippopotamus, as some taxonomists believe, one thing we know about the babirusa: it is all ugly. Sporting a pair of fearsome lower tusks for stabbing opponents, and a pair of upward-growing canines that grow through the skin and curve all the way to the eyes, which aid in grappling and butting, the male babirusa’s unique headgear makes it extremely attractive to lady babirusas, and has the opposite effect on everyone else.

The number one cause of death for babirusas is sneezing.

Do I have something on my forehead?

The footlong upper tusks are actually quite brittle and exist mainly for show, as they seem correlated with age and testosterone levels. They also provide a handy way to weed out the older babirusas who have too much testosterone.

"Epic Fail"

You would not believe this migraine I'm having.

But it’s not the babirusa’s teeth that make it the subject of today’s post, but its diet. Like a wild boar, the babirusa is an omnivore that is primarily a vegetarian and a frugivore. And like any pig, it enjoys wallowing in mud, as a healthy clay facial keeps it cool in the jungles of Sulawesi, and helps with parasites to boot. (As for the complexion, it does little in this case.) But the babirusa also eats the clay. The act of eating earth is called geophagy, and it’s practiced by many animals, including apes, birds, and elephants. And why would you want to eat dirt?

Overtones of oak and cherry, with a distinctly loamy mouthfeel.

Um, because it's effing delicious?

Zoopharmacognosy. “Zoo” = Animal, “Pharma” = Drug, “Gnosy” = To Know. Zoopharmacognosy is the process of animal self-medication, by which an animal knows to use a certain plant or soil to cure its ailments. In the babirusa’s case, the clay it eats provides it with essential minerals it doesn’t get in its diet, particularly sodium. But it also neutralizes the pH in its three stomachs: by consuming an alkaline soil, the babirusa counteracts the acids and toxins of some of the leaves it eats, allowing it to extend its diet to plants it couldn’t otherwise digest. The babirusa uses clay — and only certain clay at that — the way we use multivitamins and antacid tablets. The wisdom to know to eat one particular clay over another to ease its stomach pains is an inheritance of millenia upon millenia of culture, instinct, and ecological street smarts.

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Mongrels

Meet Kekaimalu the Wholphin. Half whale, half dolphin.


Also, annoyingly, it has dual citizenship, so it can move to Canada.

Technically, the Wholphin is the offspring of a female bottlenose dolphin and a male false killer whale, which is technically another dolphin. (As is the true killer whale.) But remarkably, she is not only a hybrid of two different species, but different genera. What’s more, she’s no mule; Kekaimalu has given birth to three healthy calves in her home in Sea Life Park in Hawaii. She is the average of her parents’ sizes and colors, being larger and darker than the average bottlenose dolphin

and smaller and lighter than the average false killer whale.

In addition, she has an intermediate number of teeth: Bottlenoses have 88 teeth, false killers have 44; the Wholphin has 66. So, the best of both worlds, right? Not so fast. Consider that Kekaimulu has only ever lived in captivity, outside of the bloody struggle of competition, and it’s unlikely she’d survive in the wild ocean. What’s more, almost all the hybrids you hear about — the liger, the mule, the zorse and the zonkey — occur in captivity, implying that hybridization between different genera is a fluke, and often an evolutionary dead end. But recently, there’s been an epidemic of hybridization in the wild, resulting in chimaera of unique proportions: the pizzly bear, a hybrid of the polar and grizzly, and the narluga, a cross of narwhal and beluga whale. Cool, right? Like a griffin, or a pegasus, or a Wuzzle? While cross-genera hybridization sounds as exciting as something out of The Island of Dr. Moreau, what it bodes for the future of the environment is just as ultimately tragic.

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