Heterocephalus Fhtagn
BY ALPER ÖZKAN (MSN/PhDII)
I must admit with no small amount of shame that there are certain animals capable of outright shattering my suspension of disbelief concerning reality. I am not alone in this situation: at least one internet denizen has, upon observing the bizarre "looping" behavior exhibited by frightened owl hatchlings, complained that owls "were laggy and had several glitches"; while another was absolutely convinced that wombats didn't really exist and were the product of a joint practical joke by reporters, zoologists and possibly God.
Perhaps we should consider ourselves lucky to live in such an interesting world, but sometimes I do end up thinking that humanity, for all its faults and vices, deserves a saner universe, devoid of football-sized single cells that craft makeshift armor glued together by their feces or mafioso ants that force their host plant to produce more food by regularly pruning its flowers (though "pruning" is almost too kind a word here, given how they're literally and repeatedly castrating the plant).
Unfortunately for mankind, bouts of zoological insanity are in fact quite common and, once in a great while, may gather in a single animal that by all odds shouldn't be, a Lovecraftian nightmare with no other purpose than to spit upon Man's eons-old dream of understanding the world around him. While the platypus (an egg-laying, duck-billed, venomous mammal that is so unusual it was thought to be a hoax -- and this was before it was discovered that its awkward-looking bill could detect electrical currents generated by muscle contractions, and that it had ten sex chromosomes) is an oft-cited example of such avatars of madness, and the parasitic, single-celled worm jellyfish Buddenbrockia is another strong contender, I am of the opinion that eyes in the storm of biological curiosity are most commonly found in humble subterranean lairs. Featuring just about every environmental extreme, the underground is nonetheless flourishing with life, and those who delve too greedily and too deep usually have to face more than just Balrogs.
One such animal is the naked mole rat, a small rodent that exists solely to serve as a gathering point for several unique traits. While mammals are widely known to maintain a stable body temperature even during rest, the naked mole rat has abandoned this system in favor of a much lower metabolic rate -- while small birds and bats are also known to "turn off" their metabolism at times, the mole rat is permanently stuck in this mode and, like basking lizards and snakes, uses behavioral adaptations to heat or cool itself. Its skin is incapable of feeling pain: dipping the animal in concentrated acid merely results in a confused mole rat trying to swim its way out. It is, alongside the closely related Damaraland mole rat, the only eusocial mammal known, which is to say each colony has a "queen" served by sterile and morphologically distinct "workers" (unlike the system operative in the case of honeybees, but like that of certain wasps, a worker mole rat replaces the queen when the current one dies). And while an average mouse would be lucky to see its third year, naked mole rats may live for thirty.
They are also immune to cancer, or at least as resistant as any animal can be. Various other animals, such as turtles and sharks, are also lauded as being cancer-proof, though tumors have been observed in them -- but not in naked mole rats (MBG students might like to know that not even transfection with potent oncogenes can induce cancer -- their cells also naturally produce telomerase and can be cultured indefinitely without immortalization). Their success lies in a two-hit contact inhibition system. In humans, as well as other mammals, cells tend to stop growing upon contact with one another. This is regulated by a vital gene, p16, the lack of which is one of the many roads to cancer. Naked mole rats have two proteins with this function (so that even if one becomes nonfunctional, the other can shoulder the task), and their cells are particularly susceptible to this mechanism, so they tend to stop growing before any of them get the chance to multiply out of control.
Two distant (and also subterranean) cousins to naked mole rats accomplish the same feat in a much more unusual (and also insane) manner: that is, by lacking an apoptosis response, caused by a mutation in the all-important anti-cancer bulwark p53 (a protein of such profound importance that it is called the guardian of the genome). Apoptosis is an "honorable death," wherein the cell neatly destroys itself without harming its neighbors, and errors in this mechanism usually lead to cancer, so it was first thought that blind mole rats (as those rodents are called), lacking any method by which multiplying cells could be told to stop, were more susceptible to cancer. It turned out that each blind mole rat cell was a ticking time bomb that initiated necrosis (the messy sort of cell death) after a certain time period, leading to its own demise alongside that of its neighbors -- including any cancer cell unlucky enough to stand in the way.
I suppose this is a good place to end the column, since I don't have much space to mention the likes of star-nosed moles (fastest eaters in the world, featuring nose tentacles and the ability to blow snot bubbles into the surrounding liquid in order to smell chemicals in water) or caecilians (snake-like amphibians with tear duct tentacles, detachable eyes and teeth-bearing offspring that rip their mother's skin off to eat). In any case, the internet covers these species quite extensively, and I highly recommend taking a look at the Tetrapod Zoology blog's series on caecilians.
And, well, watch your step.