oh ooh! Aah aah! When you go the zoo, it's always fun to watch monkeys at play. They have hands and feet and faces like us, and a quick, feral intelligence that makes them easier to empathize with than, say, squirrels. At the same time, they're dumb enough that we can laugh at them without embarrassment. Show a mirror to a monkey and it'll attack its own reflection. Heh. But just down the path, in the great apes habitat, things are a little different. Show a mirror to an orangutan and she'll start checking her teeth, combing her hair, seeing if there's anyone behind her. She gets the idea right away, without anyone explaining it to her. Orangutans are noted escape artists, too, while captive gorillas and chimpanzees have learned human sign languages and scored as high as 95 on human IQ tests (with 100 being the human average). Whether we like it or not, humans are in fact one of the four great-ape species, not nearly as different from the others as we often suppose. This is immediately apparent when you make eye contact with another ape; there's an instant connection you don't get with monkeys, and it's only a historical accident that puts you on one side of the glass and your hairy cousin on the other.
So what about the greatest ape of all? What about King Kong? The brainchild of writer/director Merian C. Cooper, Kong has just been dusted off for his 20th movie appearance by none other than Peter Jackson. Something tells me I won't win any points here by criticizing the man who brought The Lord of the Rings to life, but the protocols of science and the whips and canes of the SCI FI editorial staff demand a clear-eyed review of the facts. We know we can empathize with him, but is this giant ape really possible in the first place?
A male silverback standing 25 feet tall at the shoulder, "King" Kong is 4.5 times the size of the largest gorillas known today. In humans, the disease known as gigantism has been known to produce men as tall as 9 feet (3 m), about 1.5 times normal, while the largest primate in the fossil record is the extinct Gigantopithecus, which may have reached heights of 10 feet. This is still less than half the size of Kong, and anyway Gigantopithecus probably looked more like an orangutan than a gorilla. So the first thing we can say is that nothing like King Kong has ever lived on our planet. Even the wooly mammoth only stood 14 feet high! The blue whale can reach lengths of 100 feet (33 m), but as an aquatic creature it doesn't have to support its own weight.
And that's important, because the so-called "cube-square law" limits how big a land animal can grow without breaking its leg bones when it walks. The issue? I'm going to get technical for a moment here, so bear with me: Strength of a bone is proportional to its cross-sectional area, which increases as the square of its length. Unfortunately, the mass of a creature is based on its volume, which is proportional to the cube (i.e., the third power) of its height. In other words, if you make something twice as tall but leave its proportions the same, you end up with eight times the mass but only four times the bone strength. Snap!
The marrow of the matter
Well, actually it's not quite as bad as that. Bones aren't static objects, like bridge supports or telephone poles. Instead, they incorporate piezoelectric sensors, similar to the needle of an old-style record player that turns pressure changes into tiny electrical voltages. These voltages are sensed by the body and used to determine how much stress the bones are actually under. To adjust for wear and tear, the minerals that make up the bones' inner matrix are continually absorbed and replaced by cells called osteoclasts and osteocytes, and this sensor information is used to strengthen or lighten the bones on an ongoing basis. This is why bedridden patients, and astronauts who spend long periods in zero gravity, suffer from osteoporosis—a dangerous thinning of their bones. Conversely, the leg bones of athletes and obese people can be as much as 20 percent denser than normal.
In an engineering sense, bones are also overdesigned. An average person can easily carry another person without breaking a leg, and in fact, during a brisk run the leg bones experience forces of up to 14 times body weight. These impacts are potentially damaging, though, and if they get any higher the leg is in real danger. Even without an extra person on their backs, most runners get injured sooner or later.
Now, the film's production notes call out Kong's mass at 8,000 pounds (3600 kg)—16 times as much as a normal gorilla—which is exactly as much as legs that size could nominally carry. Unfortunately, thanks to the cube-square law, the real body mass would be closer to 40,000 pounds. We're off by almost a factor of five! But fortunately for Peter Jackson, Kong isn't a freak or a giant. Instead, he's specifically described as the last member of an unknown species. This means evolution has had a chance to tweak the design over tens or hundreds of millennia, either by beefing up the legs or by reducing the upper body mass. Although he looks like an ordinary gorilla, Kong's legs could probably be around 25 percent thicker (and therefore 56 percent stronger) without anyone particularly noticing. If he were also a bit less muscular up top than a normal gorilla, and if his lung and stomach volume were a bit larger so that more of his torso were empty space, we could probably double his overall strength-to-weight ratio while keeping that distinctively gorilloid appearance.
Also, if Skull Island offers a diet rich in the element strontium, Kong could gain an additional 14 percent increase in bone strength, meaning his limbs would be about half as strong, proportionally speaking, as a normal gorilla's. That's not too bad.
Still, we're talking about a lot of meat and bone here. Although gorillas are normally vegetarian, Kong might want to take a hint from the chimps and humans, who eat meat when they can get their hands on it. Otherwise, it'd take about four and a half tons of plant matter every day just to keep him alive. Not that that's impossible or anything; it's probably about the same diet as another prehistoric giant: the Seismosaurus. A sauropod dinosaur closely related to the diplodocus, this Cretaceous monster grew up to 33 meters long and 20 meters high, with an estimated weight of 150,000 pounds (68,000 kg), carried on four legs that were each roughly two meters across. To the best of our knowledge, Seismosaurus is the largest land animal that has ever lived, and at four times the mass of King Kong, it really did shake the Earth when it walked. Here, at least, is the proof-by-existence that Kong-sized creatures can exist.
... wherever he wants to!
So ... in my professional opinion as a science-fiction writer, King Kong should avoid running at a full sprint, and should (like a normal gorilla) do most of his walking on all fours. Otherwise, he's anatomically plausible.
And what about his rampage through New York? Gorillas are not normally that aggressive. Also, while chimpanzees display more curiosity and inventiveness, gorillas are calmer and more deliberative, and have a greater ability to focus their attention than chimps do, so in practical terms they may be smarter. Would a Kong-sized brain be brighter still? Not necessarily. Neanderthals had larger brains than modern humans do, and yet they were clearly less intelligent. Whales and elephants also have superhuman brain sizes, and while they seem to have richer emotional lives than most other animals, there's no sign that they're smarter than humans. Anyway, gorillas naturally live in bands of 6 to 30 individuals, so a lone ape would probably have the same sort of emotional and psychological problems that a lone human would. Throw in physical abuse, flashing lights and an unfamiliar and decidedly unnatural environment, and yes, we could expect any gorilla to go bananas.
On a final note, the sight of dinosaurs in 1933 raises some interesting issues. If it seems like a bit of a stretch, just remember the parable of the coelacanth, a fish dating back 350 million years. Based on fossil evidence, scientists used to believe the creature had become extinct around 60 million years ago, until living specimens were discovered by fishermen off the South Asian coast in 1938. And on a related note, a new species of small, carnivorous mammal (apparently a relative of both foxes and cats) was discovered just this week in Borneo, so it's not like we've discovered everything there is to discover. It may be unlikely that the Earth—now thoroughly explored by humans—could still contain giant living dinosaurs unknown to science, but in 1933, when the movie is set, the possibility was real enough.
So we've had a close call here, but I think we can say with reasonable confidence that when you go see the movie, you can bring your human brain along and still enjoy it. Just don't use the flash on your digital camera, hey?
Sources:
rottentomatoes.com: "King Kong"
imdb.com: "King Kong (1933)"
"Koko's World," http://www.koko.org/world/
ANATOMICA, 3rd Edition, Global Book Publishing, 2005
Gottesman, Robert: "Strontium Supplements Build Bone," The Hopkins Health Watch, Vol 1 Issue 3, July 2003
"New Animal Found in Borneo," http://dsc.discovery.com/news/afp/20051205/newcarnivore_ani.html
The Guiness Book of World Records, 2005 Edition: "Tallest Man"
DinoDictonary.com: "seismosaurus"
Freitas, Robert A.: Nanomedicine Volume I: Basic Capabilities, Landes Bioscience, 1999
The Encyclopedia Britannica, 2004 Edition: ("gorilla," "orangutan," "chimpanzee," "coelacanth,"
"mammoth," "blue whale," "seismosaurus")
Wikipedia: ("gigantopithecus"): http://en.wikipedia.org
Wil McCarthy is a rocket guidance engineer, robot designer, nanotechnologist, science-fiction author and occasional aquanaut. He has contributed to three interplanetary spacecraft, five communication and weather satellites, a line of landmine-clearing robots and some other "really cool stuff" he can't tell us about. His short writings have graced the pages of Analog, Asimov's, Wired, Nature and other major publications, and his book-length works include the New York Times notable Bloom, Amazon "Best of Y2K" The Collapsium and most recently, To Crush the Moonn. His acclaimed nonfiction book, Hacking Matter, is now available in paperback.
