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Reposted by James T. Stroud

Professor Goose @thundergoose.bsky.social · 36m

Supercool 🧵 on lizards missing limbs, some ways they adapt and how this relates to our understanding of evolution.

Once again, biology is more complicated

James T. Stroud @jameststroud.bsky.social · 2h

🦎THREAD: We just published something wild in @asn-amnat.bsky.social - lizards missing entire limbs not only survive, but some appear to actually thrive in the wild?!

Let me tell you about the "three-legged pirate" lizards 🏴‍☠️

[Paper: www.journals.uchicago.edu/doi/10.1086/... ]

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Reposted by James T. Stroud

Susan Perkins @nycuratrix.bsky.social · 2h

In my long career of catching anoles, it was not unusual to sometimes see lizards missing whole limbs. It was awesome to be part of this huge collaboration to study this phenomenon broadly!

James T. Stroud @jameststroud.bsky.social · 2h

🦎THREAD: We just published something wild in @asn-amnat.bsky.social - lizards missing entire limbs not only survive, but some appear to actually thrive in the wild?!

Let me tell you about the "three-legged pirate" lizards 🏴‍☠️

[Paper: www.journals.uchicago.edu/doi/10.1086/... ]

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Reposted by James T. Stroud

Oriol Lapiedra @oriollapiedra.bsky.social · 1h

👇 an interesting thread on this study, led by @jameststroud.bsky.social and emerged after long discussions about the limits of morphological performance in lizards with @jblosos.bsky.social.

A beautiful example of how natural history observations generate relevant debates in evolutionary biology.

James T. Stroud @jameststroud.bsky.social · 2h

🦎THREAD: We just published something wild in @asn-amnat.bsky.social - lizards missing entire limbs not only survive, but some appear to actually thrive in the wild?!

Let me tell you about the "three-legged pirate" lizards 🏴‍☠️

[Paper: www.journals.uchicago.edu/doi/10.1086/... ]

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James T. Stroud @jameststroud.bsky.social · 2h

📖 Read the full story: theconversation.com/3-legged-liz...

📄 Peer-reviewed paper here: www.journals.uchicago.edu/doi/10.1086/...

Thanks for following along! 🦎🧬

🧵 END (16/16)

3-legged lizards can thrive against all odds, challenging assumptions about how evolution works in the wild

Most lizards probably don’t survive devastating injuries. But a new study documents 122 cases of limb loss across 58 species – these exceptions shine a new light on natural selection.

theconversation.com

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James T. Stroud @jameststroud.bsky.social · 2h

Huge shoutout to our 50+ coauthors who contributed observations from decades of fieldwork!

This paper started from naturalists paying attention to the "weird" - a reminder that natural history observations, even of oddities, can spark major conceptual discussions about life on Earth! 🔬🦎

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James T. Stroud @jameststroud.bsky.social · 2h

Together, these challenge Arnold's classic morphology→performance→fitness paradigm - a foundational framework for understanding adaptation and evolution by natural selection.

The pipeline from traits to fitness...perhaps way messier in the wild than we expect?

Nature is complicated! 🧬🦎

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James T. Stroud @jameststroud.bsky.social · 2h

Principle 4: BEHAVIOR buffers selection

Organisms may change their behavior to avoid costly situations. Injured lizards might stay closer to refuges, rely more on crypsis, or switch habitats entirely.

To what extent does behavior act as a shield between organisms and selection pressures? 🛡️ (13/n)

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James T. Stroud @jameststroud.bsky.social · 2h

Principle 3: Natural selection is EPISODIC

In other words, the strength of selection varies through time. When prey is abundant and predators scarce, losing a leg may not matter.

The three-legged lizards we found might be living during periods of relaxed selection on these traits? ⏰

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James T. Stroud @jameststroud.bsky.social · 2h

Principle 2: Natural selection is MULTIFARIOUS

Selection acts on MULTIPLE traits simultaneously. A lizard with exceptional eyesight or camouflage might survive limb loss where others can't.

To what extent can high-quality traits in one area offset deficits in another? ⚖️

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James T. Stroud @jameststroud.bsky.social · 2h

Principle 1: Natural selection is PROBABILISTIC

If a three-legged lizard never encounters a predator, reduced running performance might not matter. Individual fitness isn't just about traits - it's about life's contingencies and chance encounters.

What role does luck play? 🎲 (10/n)

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James T. Stroud @jameststroud.bsky.social · 2h

Why does this matter to our understanding of evolution?

These three-legged lizards reveal 4 key principles about how natural selection might ACTUALLY work in the wild.

Let's break them down... 🧵👇

(some of these could be controversial)

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James T. Stroud @jameststroud.bsky.social · 2h

The point: Is natural selection really "daily and hourly scrutinizing" every trait like Darwin claimed?

Or is it more episodic, probabilistic, and multifarious?

These three-legged survivors suggest selection may be less omnipresent than we think 🤔

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James T. Stroud @jameststroud.bsky.social · 2h

The secret: compensation. Using @deeplabcut.bsky.social, we found injured lizards altered their gaits.

Some showed exaggerated body undulation (serpentine movement). Others cranked up stride frequency. Different strategies, same result: maintaining speed despite missing limbs! 📊🔬

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James T. Stroud @jameststroud.bsky.social · 2h

How?

We measured sprint speed in limb-damaged lizards.
Theory predicts they should be MUCH slower, right? Shorter limbs = reduced stride length = slower speeds. That's textbook biomechanics.

Wrong! Some ran just as fast - even FASTER - than intact lizards. Wait, what?! 🏃‍♂️🦎

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James T. Stroud @jameststroud.bsky.social · 2h

But wait - this should be IMPOSSIBLE, right?

Lizard limbs are a *textbook* example of adaptation.

Decades of research show even SLIGHT differences in leg length affect sprint speed, survival, and fitness.

So lizards missing entire limbs should be... dead? Yet here they were, thriving? 🤯

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James T. Stroud @jameststroud.bsky.social · 2h

The response was incredible! We documented 122 cases of major limb loss across 58 species spanning 21 lizard families on 4 continents.

From geckos to iguanas, chameleons to skinks - missing feet, legs below the knee, even ENTIRE limbs. And many looked... healthy? Fat, even? 🤔

🦎

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James T. Stroud @jameststroud.bsky.social · 2h

That moment stuck with him. Over the years, he kept finding more three-legged lizards--when we met, we talked about it and I had seen the same! So, we thought we would ask other lizard biologists... 🦎🦎🦎

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James T. Stroud @jameststroud.bsky.social · 2h

It all started with this beautiful brown anole found by @jblosos.bsky.social nearly 20 years ago! He'd marked this lizard the year before with 4 normal leg, but now it was missing its ENTIRE hind leg - yet was "fat and sassy," nimbly evading capture on narrow branches like nothing happened 🤯

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James T. Stroud @jameststroud.bsky.social · 2h

🦎THREAD: We just published something wild in @asn-amnat.bsky.social - lizards missing entire limbs not only survive, but some appear to actually thrive in the wild?!

Let me tell you about the "three-legged pirate" lizards 🏴‍☠️

[Paper: www.journals.uchicago.edu/doi/10.1086/... ]

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Reposted by James T. Stroud

IUCN SSC Chameleon Specialist Group @iucnchameleons.bsky.social · 1d

122 cases of limb loss in lizards revealed that these these rare survivors of traumatic injuries can run just as fast, maintain healthy body weight, reproduce successfully & live surprisingly long lives.
Article: www.journals.uchicago.edu/doi/10.1086/...
Summary: theconversation.com/3-legged-liz...

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Reposted by James T. Stroud

Anderson Lab @andersonlabusd.bsky.social · 1d

Some fun chameleon and Anolis contributions from the Anderson Lab to this work!

IUCN SSC Chameleon Specialist Group @iucnchameleons.bsky.social · 1d

122 cases of limb loss in lizards revealed that these these rare survivors of traumatic injuries can run just as fast, maintain healthy body weight, reproduce successfully & live surprisingly long lives.
Article: www.journals.uchicago.edu/doi/10.1086/...
Summary: theconversation.com/3-legged-liz...

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Reposted by James T. Stroud

Science X / Phys.org @sciencex.bsky.social · 22h

Three-legged lizards across diverse species can maintain healthy body weight, reproduce, and even match or exceed the speed of fully-limbed individuals, challenging assumptions about evolutionary constraints. doi.org/g96qz6

3-legged lizards can thrive against all odds, challenging assumptions about how evolution works in the wild

We are lizard biologists, and to do our work we need to catch lizards—never an easy task with such fast, agile creatures.

phys.org

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Reposted by James T. Stroud

The Conversation U.S. @us.theconversation.com · 18h

Among certain lizard species, “three-legged pirates” — rare survivors of traumatic injuries — can run just as fast as their four-legged counterparts, maintain a healthy weight, reproduce successfully and live surprisingly long lives.