Bayou-Diversity (9 September 2018) We humans describe the world that we see around us as our environment. Our perception of this world is unique in that none of the other living creatures on the planet share our experience. Each species has its own awareness of what we call the environment. The term for what an animal perceives is Umwelt, or self-world. There can be as many different Umwelten in a particular environment as there are kinds of animals.
The Umwelt for any creature is dependent upon the types of sensory receptors that it possesses and its capability to process stimuli of those receptors. Our awareness is based on the five senses of sight, smell, touch, hearing and taste, each with it own limits. Various animals have these senses and often more that function within different parameters. For example, humans have about 4 sq. cm. of membrane that detect odors. Dogs have 150 sq. cm. of this organ to find the perfect stench to roll in. Humans can hear sound frequencies between 20 and 20,000 hertz. Elephants can hear in the ultra-low range of 1 hertz, and some moths can hear frequencies of 240,000 hertz. Even Chef Paul Prudhomme had only 10,000 taste buds, but the catfish in his famous dishes have 100,000. A burrowing mole has six times more touch receptors in his nose than in the human hand. As for sight, the normal vision for people is 20/20. A hawk’s vision is equivalent to 20/5.
And then there are those animal senses that we can barely imagine. Whales and bats use echolocation to navigate. Rattlesnakes use infrared vision to hunt warm-blooded prey in the dark of night. Fish use electric fields to monitor their surroundings. Bees, sea turtles, migratory birds, and tuna can detect the magnetic fields of the earth and orient themselves with this mysterious process. It is easy to forget that the wildlife around us view reflections of southern sunsets on our bayous from a different perspective, one defined by their own Umwelt.