What the Heck Happened to our Horny Toads?
When I was a kid in the ’60s, my friends and I spent hours hunting lizards in the many vacant lots in CV. It was strictly catch-and-release, mind you. The point was the thrill of the chase, a brief moment of triumph while the panic-stricken lizard tried to squirm out of our dirty hands, and then the escape back to the omnipresent rock piles. Blue-bellies (western fence lizard) and fierce alligator lizards made up the bulk of our catch, but the most sought-after prey was the prehistoric-looking “horny toad.”
Horny toads, actually called horned lizards, have a range throughout Western North America. More than a dozen different species exist, but in our area the coast horned lizard dominates. The horned toad is the most charismatic of the local lizards, due in part to its resemblance to cartoon dinosaurs. It is flat and round, its body covered in short spikes. A wide crown or collar of longer spikes around the blunt head completes a fearsome appearance. If this weren’t fantastical enough, it can squirt a small amount of blood from its eyes from a couple of feet when threatened. Despite all these seemingly horrifying descriptions, the lizard is actually endearing in a “so ugly, it’s cute” sort of way.
But about 20 years ago this interesting little lizard that could be found in any backyard in the valley seemingly disappeared. Despite there being no shortage of other lizards, the horny toad population collapsed, so much so that they are on the verge of being declared an endangered species. Their particular lizard dynasty was destroyed by a small problem (very small – the size of an ant) – specifically the Argentine ant.
The Argentine ant is the basic black ant that we are all familiar with. But they aren’t from around here – they’re invasive. In the 1890s a little colony of Argentine ants came into California from South America with a load of coffee or sugar. This small colony has expanded into a single massive colony that incredibly now encompasses nearly the entire state. Our native ants spend a good amount of their time competing with other native ant colonies, even those of the same species. The Argentine ants, however, because they belong to a single massive colony, don’t compete with other Argentine ants, and instead focus their collective energies on destroying the native colonies. They are incredibly efficient at this, and have entirely eliminated the native ants in some areas. For those familiar with Star Trek terminology, Argentine ants are the Borg and, for native ants, “Resistance is futile.”
Why is this a problem for the horny toad? Their diet is almost entirely ants, but they hate Argentine ants! They’ll eat them if they have to, but they can’t thrive on a diet of only Argentine ants. Biologists experimenting with horny toads found that diets of exclusively Argentine ants caused weight loss and decline in the lizards. Apparently the ants don’t contain the right nutrients. Not only are Argentine ants multiplying and destroying the horny toad’s food source but now a fire ant invasion is occurring. Fire ants can actually attack and bring down small animals, and pose an ecological nightmare for horned lizards. Combine this with loss of habitat (more parking lots and housing developments), and the horny toads might soon be a thing of the past.
But I try never to be all doom and gloom. Argentine ants need more water than California can naturally supply, and a drier state means fewer Argentine ants. And biological surveys have shown that wildfire burn areas show a resurgence in native ant populations and a corresponding resurgence in the horny toad numbers. Recently one native ant population in northern California actually developed a chemical secretion that kills invasive ants. You can never predict the twists and turns of natural selection.
On a recent hike in the Verdugo Mountains I found a baby horny toad for the first time in years. After catching and releasing the cute little guy, I reflected on how much I miss the horny toad, and how much I hope for its future.