Wednesday, 21 January 2015

A Horse by Committee: Why Camels are Actually Amazing

Devoting a whole article to one animals is a little out of character for Sketchy Science. With a few exceptions that were screaming out to be explained (the disgusting lives of sloths, the indestructible tardigrades) we tend to relegate interesting facts about well-known animals to the world of Sketchy Facts. The thing is, if we tried to do that with camels, our loyal readers would miss out on a more complete understanding of one of the most incredible animals on the planet.

You often hear that a camel is just a horse designed by committee, meaning that the focus was on the details at the expense of the beauty and functionality of the overall animal. Despite the fact that no animal is designed at all, there are other reasons that this cliché is just dead wrong. All those details evolved over millions of years to make camels almost ridiculously well-suited to their environments (which, as we will see, vary insanely) and have left these creatures with a capacity to surprise that is beyond belief.

If you think you know about camels, odds are you haven’t even scratched the surface (unless you are some sort of camel biologist). Even the things the average person thinks they know about camels are just plain wrong. For example, a camels hump doesn’t store water. If it did, humps would jiggle around like elevated waterbeds with every step the animal took. In reality, the camel’s most defining feature is a massive mound of fat that can weigh as much as 80 lbs (41 kg). Having all their body fat in one place means the rest of the camel’s body is super-efficient at shedding heat, a handy adaptation to desert life. Their humps also contribute to their ability to go weeks without a real meal. They can use their humps as fuel (which is all fat really is anyway) and the longer they go without food, the more shriveled their humps get.

So if their humps aren’t thirst quenching reservoirs, how do camels go so long without drinking anything? As it turns out, camels are not the arid-loving beings we all think they are. It is true that some camels can go months without drinking water, but how they do it has less to do with storage and more to do with economy. The camels that can go seemingly forever on grass alone are the ones that are adapted to the cold areas of the Mongolian steppe. Since mammals lose most of our moisture when our bodies overheat, cold weather is a great mechanism to holding in water. As a side note: scientists think that camels actually evolved in the Canadian arctic before migrating to Asia during the last ice age. Camels also have another wacky, water-saving adaptation that is far less obvious.

If you looked at camel blood under a microscope and compared it to the blood of, say, a wombat or Bratt Pitt you would notice that the camels red blood cells look warped in the manner of a Salvador Dali painting. Camel’s red blood cells are oval (egg) shaped whereas most mammals have circular cells. The cool thing about oblong blood cells is that they can keep flowing easily, even when the liquid they flow through (plasma) starts to dry up. Their blood cells can also expand to 240% their normal size to hold water without bursting compared to 150% in most mammals. In the end, the blood cells do the trick that most people credit the humps with.

The other thing camels have going for them in terms of water conservation is that their body temperatures can vary wildly before their start to feel any stress. Humans start to feel sick if our core temperature fluctuates more than a few degrees, but camels are comfortable with an internal temperature anywhere from 33 to 40 degrees C (93 to 105 F). They accomplish this with another amazing adaptation: the ability to cool their brains independently from the rest of their bodies. Camels use their massive, cavernous nasal cavities to cool blood before it enters their brains, protecting neurons from heat damage. The veins in their heads are also located right up next to their arteries, allowing the oxygen depleted (and cooler) venous blood to absorb some of the heat from the arteries fueling the brain.

Finally, while we are hanging out in the camel’s head, there is one last crazy thing we should check out before calling it a day. If we manage to prop open the camel’s mouth without getting spit on (camel spit is actually a mix of their stomach contents and saliva, used to ward of predators) most of us will probably recoil in fear at the sight of what appear to be inch long fleshy spiked sticking out of the animal’s cheeks. The inside of a camel’s mouth looks like some kind of alien bear-trap, but those spikes are just another awesome adaptation. The “papillai” as they are called are just grotesquely enlarged versions of the same structures that human taste buds grow on. For camels, they help direct chewy food items like sticks and leaves to the stomach while protecting the cheeks and throat from damage. When you live in the desert you have to take whatever food you can get.

Hopefully you found this tangent-filled exploration of one of nature’s most amazing animals interesting and ideally you will remember all the incredible things about these misunderstood animals next time you are tempted to use a judgey cliché. Lest ye get spit on. 

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