Aug 23, 2025 12:28 AM
https://www.smithsonianmag.com/smart-new...-180987224
INTRO: When humans are exposed to lead, they can develop a host of serious health problems, ranging from reproductive issues to high blood pressure. But at least one species of lizard seems to be virtually immune to the effects of this naturally occurring neurotoxin—and researchers say the creature might hold the key to combating heavy metal poisoning in other species.
Brown anole lizards (Anolis sagrei) living in New Orleans have extremely high levels of lead in their blood, according to a new study published in the journal Environmental Research. And yet, these small reptiles seem to be completely healthy.
“What’s astonishing is that these lizards aren’t just surviving, they’re thriving with [a] lead burden that would be catastrophic for most other animals,” study co-author Alex Gunderson, an evolutionary biologist at Tulane University, says in a statement.
In New Orleans, the brown anole is an invasive lizard species that has become more abundant than the native green anole. Brown anoles, native to places including Cuba and the Bahamas, have spread across a lot of the southeastern United States.
New Orleans is a relatively old North American city, with roots dating back to its time as a French settlement in the early 18th century. This means it has “a long history with things like lead paint and leaded gasoline,” Gunderson tells Popular Science’s Andrew Paul. Over time, lead from these and other sources has leached into the city’s dirt and water.
Brown anoles, meanwhile, are relative newcomers to the city. These invasive creatures, which are native to the Caribbean, showed up sometime in the 1990s and quickly adapted to their new urban habitat. But as they skitter across the ground, the reptiles breathe in lead-filled dust and ingest contaminated bugs and water. Against this backdrop, Gunderson and his colleagues were curious to know how brown anoles were faring in the face of lead exposure.
When they analyzed blood and bone samples from roughly 100 wild brown anoles found roaming in different parts of New Orleans, the researchers were shocked to find the highest blood-lead levels ever recorded in vertebrates—concentrations that would be lethal to most other species.
On average, the 40 lizards in a high-exposure area had almost 1,000 micrograms of lead per deciliter of blood. Scientists even found one individual at more than 3,100 micrograms per deciliter. In humans, for comparison, doctors say there is no safe level of lead.
Those lizards’ average lead levels were more than three times higher than those found in Nile crocodiles, the next-highest average level ever documented in a vertebrate, according to the study. They were also about ten times greater than the highest averages recorded in endangered California condors, scavenger birds that were nearly driven to extinction because of lead exposure.
The findings suggest scientists “need to reevaluate what we know about toxicity thresholds in vertebrates,” Gunderson says in the statement... (MORE - details)
INTRO: When humans are exposed to lead, they can develop a host of serious health problems, ranging from reproductive issues to high blood pressure. But at least one species of lizard seems to be virtually immune to the effects of this naturally occurring neurotoxin—and researchers say the creature might hold the key to combating heavy metal poisoning in other species.
Brown anole lizards (Anolis sagrei) living in New Orleans have extremely high levels of lead in their blood, according to a new study published in the journal Environmental Research. And yet, these small reptiles seem to be completely healthy.
“What’s astonishing is that these lizards aren’t just surviving, they’re thriving with [a] lead burden that would be catastrophic for most other animals,” study co-author Alex Gunderson, an evolutionary biologist at Tulane University, says in a statement.
In New Orleans, the brown anole is an invasive lizard species that has become more abundant than the native green anole. Brown anoles, native to places including Cuba and the Bahamas, have spread across a lot of the southeastern United States.
New Orleans is a relatively old North American city, with roots dating back to its time as a French settlement in the early 18th century. This means it has “a long history with things like lead paint and leaded gasoline,” Gunderson tells Popular Science’s Andrew Paul. Over time, lead from these and other sources has leached into the city’s dirt and water.
Brown anoles, meanwhile, are relative newcomers to the city. These invasive creatures, which are native to the Caribbean, showed up sometime in the 1990s and quickly adapted to their new urban habitat. But as they skitter across the ground, the reptiles breathe in lead-filled dust and ingest contaminated bugs and water. Against this backdrop, Gunderson and his colleagues were curious to know how brown anoles were faring in the face of lead exposure.
When they analyzed blood and bone samples from roughly 100 wild brown anoles found roaming in different parts of New Orleans, the researchers were shocked to find the highest blood-lead levels ever recorded in vertebrates—concentrations that would be lethal to most other species.
On average, the 40 lizards in a high-exposure area had almost 1,000 micrograms of lead per deciliter of blood. Scientists even found one individual at more than 3,100 micrograms per deciliter. In humans, for comparison, doctors say there is no safe level of lead.
Those lizards’ average lead levels were more than three times higher than those found in Nile crocodiles, the next-highest average level ever documented in a vertebrate, according to the study. They were also about ten times greater than the highest averages recorded in endangered California condors, scavenger birds that were nearly driven to extinction because of lead exposure.
The findings suggest scientists “need to reevaluate what we know about toxicity thresholds in vertebrates,” Gunderson says in the statement... (MORE - details)