Tick Worlds

Jacob von Uexkull, writing in 1934, made the unusual assertion for the time that “All animal subjects, from the simplest to the most complex, are inserted into their environments to the same degree of perfection.” (50) He doesn’t mean we all have the same perceptions or same intelligence or same worlds for that matter, but he does mean that we as humans are in any way the pinnacle of evolution, the best yet at being adapted to the conditions of Planet Earth, which was a truism of Western philosophy and science of the time. What Uexkull says is rather that each creature lives in its own unique lifeworld, or Umvelt, which is created by their particular perceptual tools.

So instead of an objective world, to which each creature has particular limited access, with human beings at the top with the most, he describes interlocking lifeworlds as something like a Venn diagram of overlapping spheres, the overlap being made up of those perceptual tools we share with, say, dogs, ants or birds. A dog, of course, totally outdoes us in the power and acuity of their sense of smell, and its impossible to imagine what impact this has on the picture of the world as experienced by the dog. A bloodhound comes top of the league, with 300 million scent receptors, compared to a mere 5 million for humans.

One of Uexkull’s most famous and evocative examples of a nonhuman lifeworld is his description of the sensory perceptions of the Tick: “From the enormous world surrounding the tick, three stimuli glow like signal lights in the darkness and serve as directional signs that lead the tick surely to its target…” 51 “…this eyeless animal finds the way to her watchpoint [at the top of a tall blade of grass] with the help of only its skin’s general sensitivity to light. The approach of her prey becomes apparent to this blind and deaf bandit only through her sense of smell. The odor of butyric acid, which emanates from the sebaceous follicles of all mammals, works on the tick as a signal that causes her to abandon her post (on top of the blade of grass/bush) and fall blindly downward toward her prey. If she is fortunate enough to fall on something warm (which she perceives by means of an organ sensible to a precise temperature) then she has attained her prey, and thereafter needs only the help of her sense of touch to find the least hairy spot possible and embed herself up to her head in the cutaneous tissue of her prey. She can now slowly suck up a stream of warm blood.”


Erm, yum 😉