It is no doubt common knowledge that the leech is, by nature, a parasitic creature. Of course this well known, and yet so many of us still fall victim to the selfish intentions of the leech. Why might this be? To explain this phenomenon, there exists no greater demonstration than to compare the very natures of both the human being and the leech. We humans demonstrate remarkably complex and nuanced social interaction, a nature that is matched in few other species on Earth. As such we have been fitted with a far-spanning set of evolutionary tools in service to this communicative nature: not only vocal utterances, but detailed respiratory and vocal anatomy to support rich spoken language; a wide range of discernible frequencies of sound, specially tuned to best hear the voices of others of our kind; arms and hands and dexterous digits with which to gesture, emphasize, scribe, touch. But the grandest of these features, unarguably, is one that is oft overlooked or perhaps forgotten entirely: empathy. You see, this evolutionary focus on communication is not simply a cause of our nature, but an effect of something greater: we are inherently codependent on one another for continued survival of the species. We give, we take. At first glance this may seem somewhat counteractive to individual survival-- and indeed, you may be correct. Yet the individual is not the focus here. We see another human starving, we give them our food. Another is thirsty, we relinquish to them our water. Another is cold and wet, we offer to share our shelter. In order for this exchange to function for long-term survival, a sense of empathy is required, and it all starts the moment we gaze upon another in need. We imagine what it must be like to suffer as they do, and we selflessly offer to bear some of their burden in order to ease their suffering. The leech is not capable of such things. By stark contrast, the physical build of the leech is quite simple, efficient for the one task that evolutionary destiny has called it to. The form of the leech consists of a smooth, featureless tube, equipped with a set of blades on one end (and even in some cases, both ends.) These blades are capable of latching onto the hide of a larger organism, the mouth behind will administer an anticoagulant to prevent clotting, and from here the leech draws out the sole substance it is capable of subsisting off of: the very lifeblood of greater beings. You see where this is going, yes? While simple, the leech has developed a fascinating ability over millions of years: the leech can detect our compassion, the empathy unique and inherent to humankind, and take advantage of it. The leech looks starving, pathetic and withered and weak, and in natural response we graciously offer our own being. The key difference in this scenario, however, is that the leech cannot give anything back, neither to you nor to any host it may feed off of next. The exchange between the two species is purely one-sided, imbalanced. Parasitic. We give. The leech takes and takes and takes, yet provides nothing in return. How dreadfully selfish... To some, the leech could be interpreted as considerate. While the leech feeds off the very life force of another, it is not often likely that it-- alone, at least-- is capable of outright killing its host. The leech latches on and suckles to the point of gorging, then detaches itself as it digests its meal over the course of days, weeks, months, before finding a new host on which to feed. When compared to other parasites, at least, the leech may appear to be quite gracious. Do regard that this rather charitable interpretation is, simply put, not reflective of reality. The leech does not care for you. It does not look out for you, nor bear your interests in mind. The leech knows no bounds, and will continue to suckle on your generous arm until every last drop of life is drawn out from you. While doing this the leech may croak out a dreadful imitation of the human voice, it may claim it cares about you, it may even state that it loves you. In such cases the leech has simply taken note of your inherent empathy, something it could never attain, and has sought to take advantage of such a nature for its own selfish gain. The leech is not capable of love. Tear it off. Our empathy is not a perfect trait. Like most aspects of human nature, it is fundamentally flawed. It is easy to be taken advantage of. It can be easy to believe that even a leech can have good intentions. However it is imperative to understand that the leech is, by nature, a parasite.