Look Up, Not Just Down: Living With the Eyelash Viper

We've all learned to watch our feet here — leaf litter, tall grass, the terciopelo's favorite hiding spots. But San Mateo has a second venomous neighbor that plays by the opposite rules: the eyelash viper, or bocaracá (Bothriechis schlegelii), a small, slender snake that almost never touches the ground at all.

A different snake, a different habit

Where the terciopelo waits in leaf litter, the eyelash viper spends its life in vines, shrubs, palm fronds, and low branches, usually within a couple meters of the ground. It's named for the raised, lash-like scales above each eye, and it comes in a striking range of colors — green, brown, gray, pink, even a bright yellow morph locals call oropel. Any of these can turn up in the same patch of garden, so there's no single look to watch for.

Small, shy, and rarely serious

This is a small snake, most adults 50–70 cm, with venom that's medically significant but generally not life-threatening. Every source on it says the same thing: it wants no part of a confrontation. It doesn't chase, and it doesn't strike unless it's touched, grabbed, or pressed against. The risk isn't that it comes looking for you. It's that it rests exactly where a hand might reach.

Why lawn care matters less here

Short grass and cleared trails, so effective against the terciopelo, don't do much for this one — it isn't on the ground. What helps instead is keeping vines, hedges, and low palm fronds trimmed back from walkways, porches, and doorways, the same instinct as mowing, just aimed higher.

Moving around after dark

The eyelash viper is nocturnal, and it isn't drawn to rats and compost the way the terciopelo is — it's drawn to frogs, and frogs gather wherever insects gather, including around a lit porch after dark. A flashlight for the walk to another casita helps here just as it does for the terciopelo, and it's worth a glance at the vegetation near any lit doorway before reaching past it.

On the trail: look before you grab

The instinct to steady yourself on a vine or branch on a steep or slippery stretch is exactly the reflex that leads to a hand or arm bite. A quick glance, or a walking stick to nudge foliage aside first, does the job.

If someone is bitten

The same rules apply as for any snakebite here: get to a hospital or clinic fast, keep the person calm and the limb still, and skip every folk remedy — no tourniquet, no cutting, no ice. Costa Rica's antivenom, produced by the Instituto Clodomiro Picado, treats this species' venom effectively, and fatalities are rare with prompt care.

The eyelash viper isn't a reason for a second layer of dread on top of the terciopelo. It's a reminder that "watch your step" is only half the habit out here — the other half is watching what's at hand.

Watch your step, and your reach, pura vida.