Creatures of Habit

Here it is a lazy Saturday and my fingers are drawn to keyboard. I guess I’ve got a writing habit, which is probably a good thing for a blogger. But it feeks like a day to let my thoughts wander to the peculiar habits of the Monarch butterfly colony that spends its winters in my Northern California city of San Leandro. The Monarch is a lovely creature that has long fascinated naturalists and scientists. Among other noteworthy characteristics, it is poisonous. “Animals that eat a Monarch get very sick and vomit (but generally do not die). These animals remember that this brightly-colored butterfly made them very sick and will avoid all Monarchs in the future.” Other species of butterflies have evolved markings similar to those of the Monarch to ward off potential predators, a self-defense strategy called mimicry. Like many species of birds, some Monarchs also migrate from colder to warmer climates in the winter. Unlike birds, however, these short-lived butterflies cannot complete the round-trip in one lifetime. It takes takes more than one generation for a flock of Monarchs to make the round trip. It is the offspring of the Monarchs wintering right now in my town that will return here next January. Even more amazing, the Monarchs that make this intergenerational journey are not created equal. “Adults that emerge in early summer have the shortest life spans and live for about two to five weeks. Those that emerge in late summer survive over the winter months. The Monarch that emerge in late summer and then migrate south, live a much longer life, about 8-9 months.” I can’t imagine what mechanism, presumably coded into its genes, makes the summer-born Monarchs live fast and die young, while fall butterflies must hunker down for the long flight that became their lot through the evolutionary luck of the draw. I have always believed in free will and argued the nurture side of the nature-nurture debate. But thinking about the Monarch always makes me wonder how much of our own behavior is hard-wired -- and all the more grateful for the things about myself that I can control.