My column about Jacob and his pet tarantula led to several conversations regarding spider phobias, and that led to the internet for some interesting reading. Ten percent of Americans are affected by phobias (per the American Psychiatric Association), 40 percent of which relate to animals, and fear of spiders (arachnophobia) ranks high on that list (along with other bugs, snakes, bats, mice). (Arachnophobia is also the name of a cheesy 1990 film about a South American killer spider who hitches a ride inside a coffin to the United States, breeds like mad and, along with her offspring, goes on a murderous rampage. Probably a coincidence that one year later, a 1991 London University study of undergrads found a much higher percentage suffered spider-angst: fully 75 percent were either mildly or severely afraid of spiders).

Few U.S. spiders have mouth parts strong enough to bite through human skin (black widows, brown recluse, some wolf) and fewer yet have bites dangerous to people which means this is not likely a fear born from experience since most of us are never bitten by a spider. In a 1997 study at Maastricht University (The Netherlands), kids listed spiders as their #1 fear (ahead of #2 being kidnapped, #3 predators, #4 the dark). A 2003 Virginia Institute study of identical twins (which means, of course, identical DNA) revealed that the genetic tendencies to arachnophobia were “substantial”; the fear is inheritable.

So the best research explains that fear of spiders runs in families but is not likely something “learned” from our own or the experience of those we know. What makes spiders so terrifying? There’s likely some genetic traits carried over from our early ancestors’ ability to survive in a much more dangerous world combined with spiders’ “legginess” and resulting erratic skittering (that “otherness” which informs so many fears). Meanwhile, a spider-less world would be overrun with pest insects (and, absent spider silk, also without parachutes or bulletproof vests). I say embrace, metaphorically, our eight-legged co-inhabitants.

Ken White is the president of the Peninsula Humane Society & SPCA.