The word crepuscular is derived from the Latin crepusculum, meaning “twilight”. A crepuscular animal is one that is active only at dusk and dawn. Sometimes its a mosquito or a beetle. Often its a predator because they can still see well enough to hunt and yet be hard to detect. Sometimes the animal is only there to eat other species that are themselves crepuscular. And there is a very old ecological rumor that beavers are crepuscular, and apparently all of the Canadian park service believes it.
First: credit where credit is due. She is very, very good, and the rap is enormously clever, tight and well filmed. But I would argue that the division of science that has determined in their infinite wisdom that beavers are crepuscular is the same school of thought that produced the tireless theorem postulating that if you shut your eyes tightly enough no one can see you.
In fact, the notion that a large animal that survives entirely by digesting plant cellulose could make a living by feeding for around 40 minutes a day, during which time they also have to chop down trees, build dams and block culverts, is patently insane. How much time, for instance, do cows spend chewing?
I suppose if the animal were like an anaconda, that eats only once per month, and happily digests the other 29 days, being crepuscular would be possible. (Well, except for the cold blooded part). But willow bark is such a fibrous, nutrient-lacking diet that beavers even have to eat it twice to break it down. They can’t possibly do everything they need to do at dusk and dawn, and any field scientist in the history of the world who stayed awake to watch them in the wild would know that.
Let’s see if I can inspire a retraction….
