A Large, Invasive Lizard Was Spotted in a California Park
Hikers at Joseph D. Grant County Park, just outside of San Jose, saw an Argentine black and white tegu last week—and rangers are now searching for the out-of-place reptile
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Authorities in California’s Bay Area are on alert after a large, invasive lizard was spotted in a 10,882-acre park located in Santa Clara County.
Last week, hikers were out exploring Joseph D. Grant County Park when they came across an unusual creature lurking in the brush: a big, mostly white lizard with black stripes. It was an Argentine black and white tegu, a land-dwelling reptile that’s native to South America.
They snapped a few photos, then reported their disconcerting discovery to officials. Rangers are now searching for the out-of-place reptile, and asking members of the public to keep an eye out, too.
“These lizards are not native to the area and tend to eat bird eggs, small birds, small lizards and various small mammals and invertebrates,” Santa Clara County Parks posted on Facebook. “They are docile, so they won't harm people, but they do not belong in county parks.”
Argentine black and white tegus are native to parts of eastern and central South America, including Brazil, Paraguay, Uruguay and Argentina. Roughly 30 years ago, traders began importing them to the United States as exotic pets. However, over time, the creatures escaped or were released into the wild, where they began to develop self-sustaining populations.
Tegus can weigh up to ten pounds and can grow to lengths of nearly five feet long. As omnivores, they’re not picky about what they eat and will happily chow down on everything from vegetation to crustaceans. But they’ve also acquired a taste for eggs and hatchlings, including those of ground-nesting birds, snakes, alligators and tortoises.
Tegus have established populations in several parts of Florida, where they’ve been declared an invasive species. The lizards have also infiltrated southeast Georgia, and they have been spotted in Alabama, Texas, South Carolina and Louisiana.
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Officials in Florida are trying to trap and euthanize as many tegus as they can. However, the lizards have relatively long lifespans—they can live up to 20 years—and females can begin reproducing when they’re just a few years old. They lay roughly 35 eggs per year, on average.
“We can slow them down, but we can’t stop them,” Kevin Donmoyer, an invasive species biologist at Everglades National Park, told National Parks magazine’s Jacob Baynham in 2022. “They’re here, and they’re reproducing.”
It’s illegal to own, breed or sell tegus without a permit in Florida, Georgia, Alabama and South Carolina. However, they are legal to own in California, per SFGate’s Sam Mauhay-Moore.
It’s possible the lizard spotted in Joseph D. Grant County Park last week is an escaped pet. Over the years, tegus have made headlines in California for breaking out of their homes and showing up in unsuspecting neighbors’ backyards or wandering around on the street.
“Please do not go searching for the tegu or trap it,” Santa Clara County Parks wrote on Facebook. “If you see it, back away safely and notify rangers as soon as possible.”
Though tegus are thought to be relatively new inhabitants of the United States, research suggests they’ve lived here at least once before—between 15 million and 17 millions years ago. Scientists at the Florida Museum of Natural History recently identified a previously unknown, extinct species of tegu, based on a fossilized vertebra that had been discovered in Georgia in the early 2000s.
The creature, called Wautaugategu formidusi, likely swam from South America to the U.S. during a warm period when sea levels were higher. While W. formidusi may have temporarily thrived in its new home, the climate eventually got colder and the species died out.
