I was struck by this map depicting global distribution of the Brown Rat. Their range of habitat roughly mirrors that of human beings. Very deliberately included, I’m sure, are all of the little islands in Polynesia and in the Indian Ocean. We’ve brought rats to every spot of land on the globe. There is an island in the Aleutians, “Rat Island,” that’s infested with rats. They were first brought there by a Japanese crew who shipwrecked on the island in 1780. In the time since, the place has become overrun with rats. They’ve chocked out all other forms of life and enjoy absolute supremacy over every inch of land. The island used to be a nesting ground for millions of migratory birds. When the rats came, they flourished on bird eggs and decimated the native avian colonies.
In most places, the rat is prey to queue of predators. Few rarely live out their entire lifespans. The annual mortality rate for a typical population of rats is 95%, meaning that an astounding Ninety Five per cent of all rats alive today will be dead this same time next year. The “crude death rate,” as it’s called, of human beings living in the United States in 1800 would have been about 2 to 2.5%.
There are many animal species that seem to exist only to be a plentiful food source for all of the other animals: Herring, phytoplankton, antelope, insects. Such animals are hunted nearly every moment of their lives. They exhibit fear and alarm so commonly that it could be considered a phenotypic trait.
What is the experience of fear when it is constant? I wonder if rats sense it as something negative, or if they even could since being afraid is, in fact, implicit in being rat. Do rats who live in security and comfort suffer a kind of insanity because of it? Is there, extending from this fear, some recognition on the rat’s part of its imminent fatality? Or is it that unbroken terror and agitation actually hide the cataclysm from the rat, causing it to think only of the immediate and remain blind to the end.