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Some lizards have evolved to resist deadly snake venom

A new study led by Professor Bryan Fry at the University of Queensland offers interesting insights into how lizards have adapted to survive snake venom attacks.

Lizards and snakes have been locked in a remarkable evolutionary battle for millennia. Venomous snakes wield a powerful weapon, but their reptilian cousins have developed fascinating ways to stay alive.

Lizards, snakes, and evolution

Australia serves as a dynamic arena for an evolutionary face-off. On one side are the venomous snakes, including the lethal death adder, equipped with venom powerful enough to kill a human.

On the other side, lizards, ranging from the imposing Komodo dragon to the smaller goannas, are locked in a survival struggle.

Professor Bryan Fry and his team, partnering with museums across Australia, dove deep into this epic conflict. Their research reveals a riveting arms race.

They discovered how some lizards have cleverly evolved to resist the deadly neurotoxins of Australia’s venomous snakes.

“Australian snakes have developed potent venoms to counteract the lizards’ defenses, highlighting an intense predator-prey dynamic,” said PhD candidate Uthpala Chandrasekara. “Once the lizards evolve, the snakes fire back with even more potent toxins. It’s a biological arms race where the only constant is change.”

Lizard’s defense against snake venom

“Evolution has equipped these giant lizards with the ability to combat venoms, but not all shield themselves in the same way,” says Professor Fry. That’s where it gets really interesting.

In the battle for survival, lizards have developed some fascinating defenses against venomous snakes. Their first line of defense? A unique form of chemical resistance.

Many of these large, predatory lizards have evolved an immunity to the neurotoxins in snake venom. This venom is deadly, designed to paralyze prey by attacking the nervous system.

But for these lizards, it’s as if they’ve been granted a superpower. They can face off against venomous snakes without fearing the lethal effects of their bites.

Komodo dragon

But, not all lizards play the game of chemical warfare. Enter the heavyweights: the Komodo dragon and the perentie, Australia’s own giant lizard.

These behemoths take a different approach to defense. According to Professor Bryan Fry, they rely on sheer physical strength.

Their defense doesn’t come from within but from their armor. Thick, bone-filled scales act as a natural shield against snake bites. And if a snake does get too close?

These lizards use their massive teeth to quickly neutralize the threat, treating the snakes like “fettuccini” to be swiftly cut and dispatched. In this case, brute force trumps biochemical resistance.

Advantages of small size

Now, not all lizards are titans. What about the little ones? Smaller species, like tree monitors, have found a different path to survival. By taking to the trees, they escape the ground-dwelling predators armed with deadly venom.

This arboreal lifestyle led to an interesting shift: tree monitors gradually lost their chemical defenses against snake venom. High above the dangers of the forest floor, the need for this resistance dwindled.

But evolution is a winding road. Some of these small lizards eventually ventured back to the ground, becoming burrowers. This return exposed them to lurking dangers – the same venomous snakes their ancestors had escaped.

History of lizards and snakes

The evolutionary relation between lizards and snakes is a riveting chapter in Earth’s history, a testament to the intricate web of predator-prey relationships that shape the biosphere.

This ongoing saga, rooted in the distant past, reflects the relentless adaptation, survival, and natural selection.

Millions of years ago, the ancestors of modern lizards and snakes diverged from a common lineage. This split set the stage for a journey marked by incredible diversity.

Lizards, in their myriad forms, colonized habitats from forests to deserts. Snakes, losing their limbs, became masters of stealth and deadly precision. As these paths crossed, a dynamic predator-prey relationship ignited.

Study significance

The struggle between snakes and lizards isn’t simply about survival – it’s an engine of evolution. Venomous snakes wield potent toxins to subdue their prey, including lizards.

In response, some lizards evolved sophisticated defenses like neurotoxin resistance, a testament to the power of natural selection in shaping biological arms races. This isn’t a one-sided battle, but a constant back-and-forth, innovation met with counter-innovation.

This intricate interplay influences the broader ecosystem. Predator-prey dynamics are crucial for ecological balance, regulating populations and driving biodiversity.

Nature’s never dull

The biggest takeaway from this study? “This complex dance of adaptation has resulted in a Russian doll-like nesting of gains and losses over time and suggests that the evolutionary battle doesn’t always head in one direction,” said Chandrasekara .

Just when you think you’ve got nature figured out, it throws a curveball. Lizards gain resistance, then lose it, then gain it back. It’s proof that evolution is messy, unpredictable, and incredibly fascinating.

While there’s still more to unravel in this ongoing snake-lizard duel, remember: the next time you see a lizard basking in the sun, it might be a tiny survivor packing far more secrets and evolutionary tricks than you could ever imagine.

The study is published in the International Journal of Molecular Sciences.


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