James T. Stroud
@jameststroud.bsky.social
Asst Prof @ Georgia Tech. Evolutionary ecology using lizards 🦎🦎🦎 most interested in connecting micro-scale processes to macro-scale patterns
Great time talking to 50 10th graders from Miami's BioTECH high school about lizards and how we study them for our ecological and evolutionary research!
🦎🦎🦎
@gtresearch.bsky.social @gtsciences.bsky.social
🦎🦎🦎
@gtresearch.bsky.social @gtsciences.bsky.social
October 22, 2025 at 2:24 PM
Great time talking to 50 10th graders from Miami's BioTECH high school about lizards and how we study them for our ecological and evolutionary research!
🦎🦎🦎
@gtresearch.bsky.social @gtsciences.bsky.social
🦎🦎🦎
@gtresearch.bsky.social @gtsciences.bsky.social
Had the most amazing morning talking to the next generation of lizard biologists in Miami, Florida! Hopefully inspired some future lab members!
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October 17, 2025 at 10:14 PM
Had the most amazing morning talking to the next generation of lizard biologists in Miami, Florida! Hopefully inspired some future lab members!
🦎🦎🦎
🦎🦎🦎
I’m beyond honored and thrilled to have been selected in the 2025 class of #PackardFellows - what a dream!! 😀
No better way to spend it than right here on Lizard Island with an A+ lizard catching team!! 🦎🦎🦎
Honored to be such an amazing cohort: www.packard.org/2025fellows
@packardfdn.bsky.social
No better way to spend it than right here on Lizard Island with an A+ lizard catching team!! 🦎🦎🦎
Honored to be such an amazing cohort: www.packard.org/2025fellows
@packardfdn.bsky.social
October 16, 2025 at 10:48 PM
I’m beyond honored and thrilled to have been selected in the 2025 class of #PackardFellows - what a dream!! 😀
No better way to spend it than right here on Lizard Island with an A+ lizard catching team!! 🦎🦎🦎
Honored to be such an amazing cohort: www.packard.org/2025fellows
@packardfdn.bsky.social
No better way to spend it than right here on Lizard Island with an A+ lizard catching team!! 🦎🦎🦎
Honored to be such an amazing cohort: www.packard.org/2025fellows
@packardfdn.bsky.social
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! 🧬🦎
(14/n)
The pipeline from traits to fitness...perhaps way messier in the wild than we expect?
Nature is complicated! 🧬🦎
(14/n)
October 14, 2025 at 1:52 PM
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! 🧬🦎
(14/n)
The pipeline from traits to fitness...perhaps way messier in the wild than we expect?
Nature is complicated! 🧬🦎
(14/n)
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)
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)
October 14, 2025 at 1:52 PM
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)
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)
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? ⏰
(12/n)
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? ⏰
(12/n)
October 14, 2025 at 1:52 PM
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? ⏰
(12/n)
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? ⏰
(12/n)
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? ⚖️
(11/n)
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? ⚖️
(11/n)
October 14, 2025 at 1:52 PM
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? ⚖️
(11/n)
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? ⚖️
(11/n)
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)
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)
October 14, 2025 at 1:52 PM
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)
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)
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)
(9/n)
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)
(9/n)
October 14, 2025 at 1:52 PM
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)
(9/n)
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)
(9/n)
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 🤔
(8/n)
Or is it more episodic, probabilistic, and multifarious?
These three-legged survivors suggest selection may be less omnipresent than we think 🤔
(8/n)
October 14, 2025 at 1:52 PM
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 🤔
(8/n)
Or is it more episodic, probabilistic, and multifarious?
These three-legged survivors suggest selection may be less omnipresent than we think 🤔
(8/n)
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! 📊🔬
(7/n)
Some showed exaggerated body undulation (serpentine movement). Others cranked up stride frequency. Different strategies, same result: maintaining speed despite missing limbs! 📊🔬
(7/n)
October 14, 2025 at 1:52 PM
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! 📊🔬
(7/n)
Some showed exaggerated body undulation (serpentine movement). Others cranked up stride frequency. Different strategies, same result: maintaining speed despite missing limbs! 📊🔬
(7/n)
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?! 🏃♂️🦎
(6/n)
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?! 🏃♂️🦎
(6/n)
October 14, 2025 at 1:52 PM
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?! 🏃♂️🦎
(6/n)
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?! 🏃♂️🦎
(6/n)
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? 🤯
(5/n)
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? 🤯
(5/n)
October 14, 2025 at 1:52 PM
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? 🤯
(5/n)
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? 🤯
(5/n)
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? 🤔
🦎
(4/n)
From geckos to iguanas, chameleons to skinks - missing feet, legs below the knee, even ENTIRE limbs. And many looked... healthy? Fat, even? 🤔
🦎
(4/n)
October 14, 2025 at 1:52 PM
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? 🤔
🦎
(4/n)
From geckos to iguanas, chameleons to skinks - missing feet, legs below the knee, even ENTIRE limbs. And many looked... healthy? Fat, even? 🤔
🦎
(4/n)
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... 🦎🦎🦎
(3/n)
(3/n)
October 14, 2025 at 1:52 PM
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... 🦎🦎🦎
(3/n)
(3/n)
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 🤯
(2/n)
(2/n)
October 14, 2025 at 1:52 PM
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 🤯
(2/n)
(2/n)
🦎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/... ]
(1/n)
Let me tell you about the "three-legged pirate" lizards 🏴☠️
[Paper: www.journals.uchicago.edu/doi/10.1086/... ]
(1/n)
October 14, 2025 at 1:52 PM
🦎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/... ]
(1/n)
Let me tell you about the "three-legged pirate" lizards 🏴☠️
[Paper: www.journals.uchicago.edu/doi/10.1086/... ]
(1/n)
Amazingly successful Lab night out on campus....38 green anoles in just over an hour!
🦎🦎🦎
@gtsciences.bsky.social @gtresearch.bsky.social
🦎🦎🦎
@gtsciences.bsky.social @gtresearch.bsky.social
September 30, 2025 at 2:45 AM
Amazingly successful Lab night out on campus....38 green anoles in just over an hour!
🦎🦎🦎
@gtsciences.bsky.social @gtresearch.bsky.social
🦎🦎🦎
@gtsciences.bsky.social @gtresearch.bsky.social
Lizard drawings are the best drawings. Can't beat coming in to the lab to see this
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September 30, 2025 at 2:36 AM
Lizard drawings are the best drawings. Can't beat coming in to the lab to see this
🦎🦎🦎
🦎🦎🦎
Interested in measuring trees and branches from Lidar data? Don't want to use Matlab? (who does).
Take a look at our new Python package for reconstructing trees from point cloud data using quantitative structure models (QSM's).
Fun with @jefferybcannon.bsky.social!
ecoevorxiv.org/repository/v...
Take a look at our new Python package for reconstructing trees from point cloud data using quantitative structure models (QSM's).
Fun with @jefferybcannon.bsky.social!
ecoevorxiv.org/repository/v...
September 17, 2025 at 12:51 PM
Interested in measuring trees and branches from Lidar data? Don't want to use Matlab? (who does).
Take a look at our new Python package for reconstructing trees from point cloud data using quantitative structure models (QSM's).
Fun with @jefferybcannon.bsky.social!
ecoevorxiv.org/repository/v...
Take a look at our new Python package for reconstructing trees from point cloud data using quantitative structure models (QSM's).
Fun with @jefferybcannon.bsky.social!
ecoevorxiv.org/repository/v...
Yesterday my lab x-rayed a green anole collected exactly half a century ago at our main field research site. Super cool!
🦎🦎🦎
🦎🦎🦎
September 5, 2025 at 3:45 PM
Yesterday my lab x-rayed a green anole collected exactly half a century ago at our main field research site. Super cool!
🦎🦎🦎
🦎🦎🦎
First day of Intro Ecology at @gtsciences.bsky.social -- 150 budding ecologists in the wings! Class 1 activity included thinking about all of the abiotic and biotic factors that determine green anole ecology on campus (obvi) 🦎🦎🦎
August 18, 2025 at 5:14 PM
First day of Intro Ecology at @gtsciences.bsky.social -- 150 budding ecologists in the wings! Class 1 activity included thinking about all of the abiotic and biotic factors that determine green anole ecology on campus (obvi) 🦎🦎🦎
And a huge shout out to the other 2025 award winners! What amazing company!!
(4/4)
(4/4)
July 17, 2025 at 7:03 PM
And a huge shout out to the other 2025 award winners! What amazing company!!
(4/4)
(4/4)
For info on #foundation investing in people – scientists, teachers, conservationists and creators –
visit www.maxwell-hanrahan.org #science #philanthropy
(3/n)
visit www.maxwell-hanrahan.org #science #philanthropy
(3/n)
July 17, 2025 at 7:03 PM
For info on #foundation investing in people – scientists, teachers, conservationists and creators –
visit www.maxwell-hanrahan.org #science #philanthropy
(3/n)
visit www.maxwell-hanrahan.org #science #philanthropy
(3/n)
The away recognizes my lab's fieldwork studying the evolutionary ecology of lizards and will provide incredible support for us to continue!
(2/n)
(2/n)
July 17, 2025 at 7:03 PM
The away recognizes my lab's fieldwork studying the evolutionary ecology of lizards and will provide incredible support for us to continue!
(2/n)
(2/n)