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'Scuba-diving' Lizards Breathe Underwater By Wearing Air Bubbles On Their Noses — Just Like In A Cartoon

Scuba-diving lizards have an aquatic trick up their sleeves: They can create air bubbles on their foreheads to breathe underwater, enabling them to stay submerged for long periods and escape predators, researchers say.

In 2018, scientists captured the first-ever footage of a semi-aquatic lizard known as a stream anole (Anolis oxylophus) breathing underwater using a bubble of stored oxygen surrounding its snout — an ability that had never been seen before in lizards. Since then, at least 18 other species of anoles have been found to do this too, including water anoles (Anolis aquaticus).

However, until now, researchers had no idea if this bubble enabled these lizards to stay underwater for a long time or if it merely formed as a side effect of their water-repelling skin.

In a study published Sept. 18 in the journal Biology Letters, researchers tested nearly 30 water anoles and found that those using air bubbles stayed underwater 32% longer than anoles without bubbles. In the wild, this extra time underwater likely helps them to evade predators.

"There are a lot of threats in their environment, and it makes sense that they would evolve a unique way of dealing with them using the resource — water — that they have available," study author Lindsey Swierk, assistant research professor in biological sciences at Binghamton University in New York, told Live Science in an email.

Related: Watch chameleon erupt in color 'as if uttering her last words' in her final moments before death

Semi-aquatic water anoles spend most of their time living on boulders close to river banks in forests in Costa Rica and Panama. They are small lizards that can grow up to 8 inches (20 centimeters) long. When threatened, they have been observed jumping into nearby water to escape.

"We know that they can stay underwater at least about 20 minutes, but probably longer," Swierk said.

Upon diving, these anoles exhale to create a bubble that surrounds their head, held on by the lizards' water-repelling skin. "When water anoles dive, their hydrophobic ("water-repelling") skin keeps a slick of air over the body surface," Swierk said.

As the anoles exhale and inhale, the bubble expands and collapses. The researchers suggest this redistributes air on and in an anole's body, giving it sufficient oxygen for long dives.

To test this, scientists collected 28 water anoles from the Rio Java in Costa Rica. The team applied a substance to 13 of the anoles' heads to stop their skin from being water repellant, meaning the bubble would fail to attach, Swierk said.

"We then compared the dive length and the ability to rebreathe bubbles in anoles with and without emollient applied," Swierk said.

In the control group — the anoles with no substance applied — the longest dive recorded was 477 seconds (nearly eight minutes), although this was excluded from the analysis for being an outlier. The longest dive included in the analysis was 308 seconds (just over five minutes). In the group with the substance applied, the longest dive was 254 seconds (over four minutes).

On average, anoles without the substance applied spent 67.5 seconds longer underwater than those with the substance. "These results show that when semi-aquatic anoles are allowed to rebreathe using bubbles, they can dive longer," Swierk said.

Swierk suggests the difference between dive times may have been greatly different if this experiment was conducted in the wild and not in tanks. "The pressure to stay concealed from a real predator, which we didn't use in our study, could nudge the control group's dive times much longer," Swierk said.

Anoles are not the only animals known to use bubbles underwater. For example, diving beetles carry trapped air behind them at the tip of their wing covers. This bubble acts as a "physical gill," exchanging oxygen with the water to replenish the supply inside the bubble.

The team now wants to find out if water anoles use their breathing bubbles in the same way.

It's Not Easy Being A Green Anole

Green anoles are less frequently seen near the ground as brown anoles become more prolific, instead evolving to a better suited life in the tree canopy. (Augustus Hoff/WUFT News)

She sits, her sleek, green body invisible in the tangle of leaves, and waits.

High up in the trees, in her favorite hunting spot, the green anole is patient, her bright, black eyes swiveling independently of each other, searching for the smallest flicker of movement.

The green anole isn't picky when it comes to food. Special sensors on her tongue will let her know if what she catches is edible, and most anything able to fit in her mouth will do just fine as a meal.

A slight rustle of branches dissolves the silence of her vigil. Her eyes pause their scanning, then snap in tandem to the roach that has just landed on a branch about 10 inches from her face. The bug is oblivious to the silent, scaled creature that could spell its demise. Now 3 inches away, 2 inches…

The anole strikes forward, breaching through her protective canopy of leaves towards the roach. She crunches her mouth down around the roach, its struggle to escape ceasing as she swallows it whole. Satisfied, she climbs up once again to her favorite spot, a cleverly camouflaged crusader among the leaves.

Green anole lizards, the only anole native to North America, stalk the treetops across the southeastern United States.

Many Southerners witness these friendly creatures hunting for moths near the porch light. They might remember summertime stretches of childhood boredom spent catching green anoles and coaxing them to bite down on the soft flesh of their earlobes, wearing the live green earrings with pride, always a nice shock to the grown-ups.

Anoles display their own fanciful adornment. Males have bright red neck flaps known as dewlaps that puff out from under their chin in a crimson crest when calling for a mate or challenging another anole to a duel.

They pump their bodies up and down in an impressive show of their pushup abilities, like middle-school boys in a gym-class contest. They "drop" their tails to distract a predator, or mischievous child, the detached appendage wiggling with a life of its own, allowing the crafty crawler to slip away.

But today, the green anole faces a more dire threat. Its new competitor is none other than its own cousin: the brown anole.

Since the 1940s, the brown anole, otherwise known as the Cuban or Caribbean anole, found its way to Miami and has since spread rapidly across the South. As climate change expands its warm, habitable range northward, the prolific nonnative lizard is spreading further across the American South.

"It's really good at traveling with humans," said Yoel Stuart, an assistant professor and evolutionary ecologist at the University of Loyola Chicago who specializes in evolutionary biology through the study of the green anole.

The brown anole is not picky about its mode of transport.

It travels in the wheel wells of cars, in the hidden crevices of boats and shipping containers, tucked away in bundles of firewood and, most frequently, in exotic plants, carted from lands afar and put up for sale at garden centers across the U.S.

The brown anoles are much more aggressive than the greens. They outcompete green anoles for food on the ground, fight even harder for territory and have even been known to prey on green anoles.

Plus, they're everywhere. In Florida, brown anoles are now the most abundant vertebrate, according to Stuart. Researchers there put their numbers at 10,000 per hectare, or more than 5,000 lizards in a single acre.

Anoles lay eggs every four to six days during the spring and summer, and it takes only a little more than a month for baby anoles to emerge.

Brown anoles, native to Cuba and the Bahamas, have encroached on the territory of the green anole in the Southeast, forcing the green anoles to adapt to life in the treetops. (Getty Images stock)

But the story of the anoles is more than just a lizard battle royale.

Their story of survival is also the story of human survival.

Biodiversity supports the stability of food chains and ecosystems, which provide sustenance and income for people and protect the built environment from natural disasters. The introduction of species to an environment can have complex, unintended consequences that impact people, animals, plants and the landscape itself.

The case of the anoles is one small instance of how something as simple as a stowaway lizard can have a massive effect on ecosystems.

The brown anoles were not necessarily spread with intention by humans like other invasive species such as kudzu, nutria or Burmese pythons. But negligence and willful ignorance can have just as powerful an effect.

Green anoles, previously left undisturbed on the entire continent, have never faced pressure like they do from brown anoles today.

In a turn of events that intrigues evolutionary biologists, the presence of the brown anole on the ground has pushed the green anole from the lower parts of trees upwards, climbing skyward for a new chance at survival. There in the canopy, something extraordinary happened.

"As anoles moved up into the trees, they tended to have larger toe pads," Stuart said. "The exciting bit about that is, it happened quite fast," he said.

Evolutionary change typically happens on a timescale of hundreds of years, if not thousands. This 5% increase in toepad size for green anoles happened over the course of only 20 generations.

This means that, with an average life span in the wild of 5.5 years, this evolution is happening on a fast track within the last century.

That's like seeing the average height of humans going from 5-foot-9 to the size of "NBA players," according to Stuart. It's a brown anole world in the modern-day South, and the greens are changing in order to survive.

These little green lizards show remarkable resilience. Faced with the options of total domination or change, they've adapted to the new world they find themselves in, those larger, grippier toes learning to climb on ever more delicate branches high up above the ground because they have to. Change is the only option for them.

But a new home higher up in the canopy isn't necessarily what will save the green anole.

Knight anoles pose a threat to their smaller, green relatives. They are 13-20 inches in length, about 20 times heavier, compete for the same food sources and even eat adult green anoles. (Getty Images stock)

Martin Main, professor of wildlife ecology and conservation at the University of Florida, said the knight anole — another invasive, even more aggressive, predatory lizard from Cuba, also poses a serious threat to the green anole.

They eat the same food as the green anole, prey on adult green anoles and live mostly an "arboreal" lifestyle, according to Main.

Knight anoles are also huge by comparison, at 13-20 inches in length and weighing in at close to 5 ounces at their largest — or about 21 times the size of the green anole.

The potential loss of the green anole comes with the potential for biodiversity losses, too.

Lots of species diversity means better chances of survival against diseases, severe heat and changes to the environment; all features associated with a warming global average temperature.

A loss of biodiversity can lead to a "homogenization" of species in that niche of the food web, meaning only one species is occupying that space. This can have unintended consequences.

"If everything is exactly the same, there's going to be very little of that variety that provides us resistant individuals that allow a particular species to continue," Main said.

One study from The Royal Society Publishing found that brown anoles as more vulnerable to extreme temperatures caused by climate change than green anoles. The loss of brown anoles to extreme heat after after out-competing green anoles could result in the spread of diseases, with fewer creatures to eat pests like mosquitoes and attract their bite.

This disruption of the food chain could lead to the spread of insect-borne diseases such as West Nile virus.

Lawrence Reeves, entomologist, assistant professor and researcher at the Florida Medical Entomology Laboratory, described how lizards are "dead-end hosts" for the West Nile virus, meaning that lizards cannot pass on the virus when bitten by an infected mosquito, unlike other animals that harbor West Nile.

"Every bite that goes toward a lizard is a bite that goes away from a bird or a mammal," Reeves said.

A green anole waits patiently by a spider's web for a meal at La Chua Trail in Gainesville, Florida. (Augustus Hoff/WUFT News)

This is just one instance of how life could be affected by the loss of a species. Ecosystems are so complex and delicately balanced that it can be hard to determine what impact an introduced species will have, experts say.

"By introducing new species and causing native species to disappear, we're fooling with stuff that we don't really understand," Main said. "You never really know what's going to happen when things change in an environment. It's so complicated."

Consider the green anole roach hunter who used the structures available to her: green leaves, brown stems and extra grippy toes. She took advantage of her natural surroundings rather than seeking to become dominant over them.

The idea that humans better connect with their environment when viewing their place on the planet as part of a system isn't new. In Rachel Carson's iconic environmental book "Silent Spring," she argues that "man is a part of nature, and his war against nature is inevitably a war against himself."

Jennifer Skene, clinical lecturer at Yale Law School and the natural climate solutions policy manager with the Natural Resource Defense Council, describes how that shift in thinking can allow humans to adapt just as the green anoles have.

"I think conceptually, the way that conversations are moving gives me a lot of hope," Skene said. "The rights of nature, conversations about rights of animals and animal welfare, and the way that we think about all of these is interconnected."

Like the SC Daily Gazette, Louisiana Illuminator is part of States Newsroom, a nonprofit news network supported by grants and a coalition of donors as a 501c(3) public charity. Louisiana Illuminator maintains editorial independence. Contact Editor Greg LaRose for questions: info@lailluminator.Com. Follow Louisiana Illuminator on Facebook and X.

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What Is Up With All The Brown Lizards In Houston? The Difference Between The Green Anole And Brown Anole

HOUSTON – If you've lived in Houston or Southeast Texas for any period of time, chances are you have probably noticed the small green lizards known as the Green Anole.

These guys are one of the most common species of lizards in our area and can often be seen scurrying along fences, on the sides of potted plants, or climbing up area trees.

Something I have noticed this year is it appears there are way more brown lizards then green ones showing up in the area.

There is another species of lizard that has been introduced into our area that competes with the native Green Anole. This lizard is known as the Brown Anole.

However, just because a lizard is brown does not necessarily mean it is actually the Brown Anole species.

What's the difference? Photo courtesy mypetjoy.Com

The area's native Green Anole prefer to live more on trees than on the ground. Brown Anoles by contrast are more comfortable scurrying along the ground.

Green Anoles, as their name suggests, are normally green, but depending on certain environmental conditions, they can turn dark brown. Brown Anoles are always either gray or brown.

Both male Green Anoles and Brown Anoles have dewlaps, which are large throat fans they use to communicate with each other. The dewlap is used for attracting females during mating season, communicating when anoles enter each other's territories, as well as establishing dominance over each other. In the Green Anole, the dewlap is pink while in the Brown Anole, it is orange.

Brown anole lizard (University of Florida)

Unlike the native Green Anole, the Brown Anole is actually an invasive species to the southeastern United States. They are native to Cuba, the Bahamas, and places like Jamaica and the Cayman Islands.

Brown Anoles are also more susceptible to cold temperatures than Green Anoles.

Have you seen anoles in your yard?

If you have seen either Green Anoles or Brown Anoles in your yard, we want to hear from you.

What are your thoughts on them? Do you enjoy seeing them? Do you consider them a nuisance?

We also want to see your photos of these guys. You can send your photos to Click2Pins here.

Fish and Amphibians