Rattlesnakes in Nuevo León: How to Identify Them, What to Do If You Meet One and First Aid

For practical purposes, there are only two kinds of snake envenomation in Mexico, and treatment depends on which one you got.

• Vipers: rattlesnakes, cantiles and nauyacas. Their venom destroys tissue. The area swells from minute one and the damage is local and progressive.
• Elapids: coral snakes. Their fangs are short and fixed, at the front of the mouth. Their venom is neurotoxic: it does not destroy tissue, it causes flaccid paralysis. It can fool you because symptoms sometimes take up to 12 hours to show.

And here is the point that matters most: Mexico has only two antivenoms, one for vipers and one for coral snakes. So if you get bitten, the most useful thing you can do —after calming down— is take a photo of the snake. Not so you can identify it, but so the hospital knows which of the two to give you.

This is the fact that most changed how we walk, and probably the most important one in this guide.

The image we all carry is the rattlesnake coiling into an S and making its stay away sound. That still happens in remote areas like China and Los Ramones, where snakes still have to defend themselves from coyotes and bobcats. But in Mina and García the opposite is happening: the specimens found today barely make noise and stay completely still. You can be thirty centimeters away and the snake will not move.

Why? Because the ones that rattled gave away their position and people killed them. The quiet ones survived and bred. It is not that they learned to keep quiet: we are selecting for silent snakes, generation after generation. It is evolution happening in front of us, driven by the habit of "a snake I see is a snake I kill".

The practical consequence for you is direct and uncomfortable: you can no longer count on hearing the rattle. You have to walk watching where you step and where you put your hands, instead of waiting for the snake to warn you.

Let us start with the serious part: the coral snake is dangerous. Its venom is neurotoxic —it does not destroy tissue, it paralyzes— and it has a trap that makes it especially treacherous: symptoms can take up to 12 hours to appear. It bites you, you feel fine, and hours later you start losing the ability to fix your gaze or to coordinate. That is why a coral snake bite means going to hospital immediately even if you feel nothing, with 24 hours of observation recommended.

That said, the good news is that it is very hard for one to bite you, and it is worth understanding why. Its fangs are short, fixed and very small, so it needs direct skin contact. In practice it only happens if you step on it barefoot, if you grab it, or —this happens more than you would think— if you kill it and then handle the head, because the muscles stay active for a couple of hours. Ordinary shoes protect you; you do not need steel-toe boots because of a coral snake.

It does not hiss or lunge either. Its defense is to hide its head among its coils and raise its tail, waving it to distract you. Leave it alone and it has no way of reaching you.

The one we have in Nuevo León and Coahuila is the Texas coral snake, and it does follow the red-yellow-black-yellow pattern. That rule works well here, as long as you do not meet an odd, albino or melanistic individual. It is slim and small —a one-meter animal is already huge— with tiny eyes because it barely uses them: it is fossorial, burrowing and moving through leaf litter. One caveat: in Mexico there are more false coral snakes than true ones, so most of the ones you see are not the venomous one. But it is not your job to tell them apart in the field: treat them all as the real thing and do not touch them.

Rule number one is the simplest and the one that prevents the most accidents: do not bother them.

The fright is unavoidable —fear of snakes is factory-installed in primates, even those that have never seen one— but it lasts two or three seconds. After those seconds, all you have to do is walk around it and carry on. Do not move it, do not poke it with a pole, do not try to relocate it.

Handling snakes with a hook is for trained people who can identify them. If you do not know the species and lack that practice, trying is exactly how people end up bitten.

If you are left wondering what it was, photograph it from a distance and post it to an identification group or to iNaturalist. It is infinitely safer than getting close enough to count its scales.

First, the part that lowers the anxiety: it is very rare for anyone to die from a snakebite if they get treatment. The clock starts at the moment of the bite, but it is not a countdown in minutes.

1. Calm down. The fright lasts two or three seconds; after that you need a clear head.
2. Remove rings, watch, bracelets and any tight clothing from the affected limb. It will swell from minute one, and if you do not do it now, they will have to be cut off later.
3. Take a photo of the snake. That determines which antivenom you get: there are only two, one for vipers and one for coral snakes.
4. Wash the wound with soap and water. Nothing else.
5. Start walking down, calmly and at your own pace. Do not run: raising your heart rate speeds up distribution of the venom, which is already in your bloodstream.
6. As soon as you have signal, call ahead to the hospital to say you are bringing a snakebite and your estimated arrival. In Monterrey, the Hospital Universitario always has antivenom.
7. Get there and insist on the antivenom. This is a medical emergency.

The reasonable margin is about 4 hours to reach hospital: within that range there are usually no permanent effects. Past 6 or 7 hours the risk of lasting damage begins, including kidney problems. And something worth understanding: antivenom stops the venom from acting, but does not restore what has already been destroyed. That is why time matters.

With coral snakes the math changes: symptoms can take up to 12 hours to appear, so the advice is to go immediately even if you feel fine and stay 24 hours under observation. Warning signs: not being able to fix your gaze, drooping eyelids, trouble coordinating.

Almost all the extra harm in a snakebite comes from home treatment. None of this works:

• Tourniquet. No, not for a viper bite.
• Sucking out the venom. Neither with your mouth nor with the extractor kits on sale. Venom enters the bloodstream immediately and cannot be pulled back out. Also, if whoever sucks has a mouth wound, they get envenomed too.
• Cutting or cauterizing the wound.
• Ice.
• Electricity. Yes, someone has used a personal-defense taser.
• Alcohol, neither drunk nor applied: it is a vasodilator.
• Strange remedies. Wild herbs, the snake’s own flesh or blood, and worse. There is a documented case of someone tying a duck to their leg, and another who applied a cow-dung dressing and made punctures: that person died, but of septicemia, not of the venom.

The one exception is the coral snake: there a pressure bandage —which does not cut circulation, only compresses slightly— can be used, because the venom is neurotoxic. But if you do not have one at hand, do not waste time looking for it: the gain is tiny compared to getting to a hospital.

One last point almost nobody knows: a second bite can be worse than the first. Your immune system already recognizes the venom and can overreact, like a severe allergy. There is no such thing as "building up a tolerance".

• "If a viper bites you, you have to kill it, because it gets used to it." False. Snakes do not hunt humans: we are not prey. A bite to a person is always defensive.
• "It latches on." Vipers bite and release; their skull is flexible and the strike is a defensive move, not an attempt to eat you. Coral snakes do tend to hang on a bit longer.
• "Killing them makes the mountain safer." Quite the opposite: that is exactly what is producing silent rattlesnakes in García and Mina. Killing them removes your alarm.
• "You should raise the bite above your heart." It makes little difference; walk down calmly and get to a hospital.
• "Repellents work." They do not.

It is worth remembering why this matters beyond your own safety: snakes control rodent populations, and where there is trash there are mice, and where there are mice there are snakes. Cutting down on trash in the mountains is, literally, a way to have fewer encounters.

On our route cards we use the Cascabel icon to flag the trails where you are most likely to meet them. You can review them in the catalog, ordered from the easiest routes to the most demanding:

Hiking Route Catalog near Monterrey | La Cumbre Cotidiana

You can also learn how we rate physical effort, technical difficulty and exposure on each route in our difficulty classification page:

Difficulty Classification (lacumbrecotidiana.org)