What if you could improve the human race by splicing in some animal parts? Would we be better off with cats' eyes? What if you added the lungs of a goose, the muscles of a chimp, and the circulatory system of a penguin? Let's discover which animal parts could enhance our feeble human bodies.
Top image: Brittany Greene/Flickr
Let's face it. Compared to most animals, humans are the sensory equivalent of those creepy eyeless cave fish (only we don't have the whiskers to guide us). We're just a sad bunch — not smelling, seeing, tasting, or hearing nearly as much as any of the creatures around us. It's time to fix that.
First, we need to start with the eyes. Our eyes have rods and cones, which allow us to see black, white, and three colors, the combination of which give us the "visible spectrum." Birds eyes have special double cones, plus cones that contain a droplet of oil that filters light and allows them to see more specific wavelengths.
Birds can see five colors, which would not only enhance our appreciation of the world, but give us a way to see ultraviolet light-reflections in flowers, off reflective surfaces, and off certain fluids. Wouldn't it be nice to know if a patch of grass you're about to sit on was recently peed on by a dog?
The double-cone structure also lets birds see motion faster than humans can — this gives them a head start when it comes to reaction time. And just to top things off, birds' right eyes have cryptochromes, or special proteins that let them see magnetic fields. And finally, for eye protection, we have to turn to the stately crocodile. They have an extra lid that they can shut over their eyes, letting them see in saltwater without ocular damage.
But what good are eyes if they barely function at night? Other creatures possess a layer of cells called the tapetum lucidum. It's a simple reflective layer at the back of the eye that shoots incoming light out across all the light receptors again, doubling the incoming amount of light. This is why cats' eyes shine in the dark.
But why rely on eyes (which can only see the present) when we can rely on smell (which can see the past)? Dogs' sense of smell allows them to understand what happened in a place days, weeks, months, or years ago. And it doesn't even take a giant tweak. They just have 230 million olfactory cells, or about forty times as many as we do. There has to be a way of making our nasal cavities bigger or more efficient.
Fractals have shown us that it's possible to make pits in tissue, and pits in those pits, and pits in those pits, until the entire tissue becomes like a sponge with a massive amount of surface area. True, that would make the nose more delicate, but it's already a delicate area.
And lastly, there's taste. To be honest, I don't think we need to improve taste, but there are a few things we could do to make it more fun. If we want to taste things right now, we have to put them in our mouth. This is both unsanitary, and triggers the instinct to chew, which then pulls the thing down into our stomach, and brings up the calorie count.
Catfish have taste buds all over their bodies — if we had one section of our outer body that could just taste things for us — say a patch of skin on one forearm — we could just tape a piece of chocolate to our arms and have dessert all morning.
But sense just isn't enough. Compared to the paragons of the animal kingdom, we're not fast — and although our size gives us an advantage over many animals — we're not very strong. Something needs to be done about this.
Because muscles are complicated, it's best to turn to our near-relatives for improvements. The fastest land animal is still the cheetah, but its speed lies mostly in its shape and in its oversized heart. We need something that will make the actual muscles fast. A bat's muscles move around a hundred times as fast a human muscles do (and the muscles in a bat's larynx move faster than that).
Scientists believe the source of this speed is the sarcoplasmic reticulum, a store of calcium in the bat's muscle cells that spring into action and make the muscles contract extremely quickly. We'd have to increase our calcium intake, but this is worth choking down some yogurt.
Next we need strength, and for that we need to go a little closer to home. Chimpanzee muscle fibers are approximately five times as strong as human muscle fibers. This has a specific fix. There are genes, in humans, that limit muscle development. These same genes are in chimpanzees, but they've been deactivated. Deactivate them in humans as well, and they'll have more muscle development. Chimpanzee muscle fibers are also longer than human being's muscle fibers. The fibers contract to contract a muscle, so a chimp's muscle contraction will naturally do more work than a human's.
So far we've looked at the superficial stuff — let's take a look at the interior, starting at the bottom of the world. Down in Antarctica, penguins spent entire winters huddled around together to survive the elements. Although their bodies are layered with insulation, their feet are exposed.
It seems like either the feet would freeze off, or the incoming rush of cold blood would freeze the rest of the penguin. They've gotten around this like many cold-weather animals do: excellent plumbing. Outgoing blood, about to be exposed to the cold and lose a lot of its heat, is routed right near incoming blood from the feet. What happens is a heat-exchange. The cool incoming blood is given rush of heat before it comes back into the body. The outgoing blood cools down, still delivering heat to the extremities, but losing some of its extreme heat, which would have been sucked away by the ice and snow anyway. It's a much more efficient system, made with only a few changes to blood vessel placement, and we should have it.
While we're making adjustments to how the blood flows, let's tweak the blood itself Why bother adding that clear eyelid that we get from crocodiles if we can't go in the water? There are a few problems with aquatic life - the primary one being that we need air.
The secondary problem is that, when we have air but we go too far down, it dissolves into the blood and then bubbles up again during the release of pressure when we surface. These bubbles can kill us. Seals don't seem to have this problem. They dive deep, and they do it without bubbles in the blood. But these bubbles are a result of pressurized gas. And when you bring gas (such as the gas in the lungs) underwater, it will always be under pressure. That's physics, not biology. The seals can't overcome that, but they can circumvent it.
Seals simply empty their lungs of oxygen before they dive. No gas, no pressure difference, no bubbly blood. They manage to do this by transferring all the oxygen in their lungs to the massive quantities of hemoglobin and myoglobin, two proteins that grab oxygen and ferry it around the body, in their blood. We have these proteins as well. We just need more. Then we'd be able to dive like seals, and stay underwater.
But what's the good of having a lot of oxygen underwater if we can't even oxygenate ourselves on land? Put a human too far up in the world and they'll just flat-out drop over from lack of oxygen. The increase in hemoglobin and myoglobin will help that, but how to get oxygen in there in the first place? Once again birds need to be our inspiration.
The Himalayan goose is the perfect oxygenator. It literally lifts itself over Everest twice a year when its migrating, and for that to work its muscles need to be oxygenated with as little effort as possible. It does this by having little balloons at the bottom of its lungs. When oxygen floods into human lungs, it fills the little sacs called alveoli inside each lung. Blood passes along the alveolus wall, picks up oxygen, drops off carbon dioxide, and then the lungs exhale, pushing the gas out again.
During this exhalation period, humans don't pull in any more oxygen. But these geese do. The small balloon-like sacks at the bottom of their lungs fill up with extra air during the inhalation. When humans exhale, the sacks squeeze out that air, which again fills the tiny alveoli with oxygen. The goose literally gets air twice with each breath. If we were to engineer ourselves right, even breathing would be easier.
And so we have the ultimate human. No messing around in the brain. No cat-like face or giant teeth. No paws, no claws, no gaping maws. Just a few internal tweaks that could let us swing through the trees like chimps, dive like seals, run races with cheetahs, breath easier underwater and above the clouds, and see and smell everything. It's enough to make you think that scientists need to get a little madder.
Bottom image: Brian Bolland's and Travel Foreman's Animal Man. Eyes Image: Funny Crazy Animal Photos. Bat Image: Wiki Commons Seal Image: US Fish and Wildlife Service. Via PBS, Web Exhibits, University World News, eHow, Ask a Biologist, and Audobon Magazine.