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George Lauder

@georgelauder.bsky.social
1.2K followers 399 following 288 posts

Prof. at Harvard University: research on fish biorobotics, biomimetics, biomechanics, morphology, shark locomotion and skin function, and fish schooling people.fas.harvard.edu/~glauder/ and scholar.google.com/citations?user=s…

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George Lauder @georgelauder.bsky.social · 03/02/2025
4. The keel lateral line canal (pink color) is quite strange: neuromasts are surrounded by modified scales (shown in blue), and keels have an odd set of elongated skeletal elements posteriorly. Tuna keels are clearly mechanosensory.
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George Lauder @georgelauder.bsky.social · 03/02/2025
3. Now, a team led by @juliachaumel.bsky.social and published in iScience @cp-iscience.bsky.social shows that tuna keels have a sensory function too! Each keel has a peculiar lateral line canal with small tubules that extend to the upper and lower keel surfaces (www.cell.com/iscience/ful...
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George Lauder @georgelauder.bsky.social · 03/02/2025
2. And here’s a view of the caudal fin and keels from behind during #tuna locomotion. Our previous work has shown that the keels decrease power requirements during swimming, likely by reducing lateral forces and yaw torques. But wait, there's more!
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George Lauder @georgelauder.bsky.social · 03/02/2025
1. #Tuna have well-developed bilateral keels extending to the right and left sides at the caudal peduncle area just in front of the tail. This movie shows the keel area during locomotion in yellowfin tuna. What is the function of keels in #tuna? A🧵 and new hypothesis.
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George Lauder @georgelauder.bsky.social · 22/01/2025
We propose that the ray tail acts like a “hydrodynamic antenna” providing detailed information to the ray on water movement behind the body. This video shows the effect of moving water near the tail of a cownose ray as it passes by.
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George Lauder @georgelauder.bsky.social · 22/01/2025
There are paired lateral line canals along both sides of the entire length of the tail with a remarkable branched structure that ends at the tail surface with clusters of pores. Each canal has a continuous neuromast that extends the entire tail length!
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George Lauder @georgelauder.bsky.social · 22/01/2025
What is the function of the elongate tail in elasmobranch #rays? A 🧵 and a new hypothesis. A paper with @juliachaumel.bsky.social in @royalsociety.org Proceedings B (shorturl.at/PmfYD) shows that the tail of cownose rays (and a few other species studied so far) has an elaborate lateral line.
The elongate tail of a ray
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George Lauder @georgelauder.bsky.social · 31/12/2024
What is the significance of the tremendous diversity of #shark skin #denticles? Presenting our experimental approach to understanding this at the Atlanta #SICB2025 meetings. Come to the session for all things shark skin!
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George Lauder @georgelauder.bsky.social · 28/06/2024
This occurs largely because individuals within the school alter the flow environment with their undulating bodies and proximity: fish within schools in turbulence swim more closely together as speed increases compared to schools in laminar flow:
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George Lauder @georgelauder.bsky.social · 28/06/2024
We showed that swimming in turbulence by fish schools dramatically reduces both the cost of swimming (orange curve, left panel, compared to purple curve), and the cost of transport (right panel) when in turbulence compared to individuals swimming alone.
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George Lauder @georgelauder.bsky.social · 28/06/2024
A new idea: the “turbulence sheltering hypothesis”. Fish in a school could modulate surrounding turbulence so that chaotic fluid motion increasing swimming cost is less. Fish in a group would use less energy compared to swimming alone in turbulent conditions.
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George Lauder @georgelauder.bsky.social · 28/06/2024
Why do #fish swim in #schools? A🧵and new hypothesis. Schooling could help fish avoid predators, navigate, communicate, find mates and food, and save energy. Here we propose and test a new hypothesis: tinyurl.com/yc764d74
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George Lauder @georgelauder.bsky.social · 21/02/2024
There are a wide variety of hydrodynamic mechanisms that allow energy savings as fish swim near each other and in each others wake, and fish in schools are changing relative positions dynamically through time.
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George Lauder @georgelauder.bsky.social · 21/02/2024
We also showed that schooling fishes saved relatively more energy as they moved faster compared to solitary fish, and that the cost of transport curve is also U-shaped with clear benefits to swimming in a group.
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George Lauder @georgelauder.bsky.social · 21/02/2024
By swimming both schools and solitary fish over a wide range of speeds, we showed that (1) very low speed swimming involves as much energy use as swimming at 3 body lengths/sec, and that the metabolism-speed curve is U-shaped over this speed range.
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George Lauder @georgelauder.bsky.social · 21/02/2024
And, we need to study school and solitary swimming over a range of speeds and measure energy use both during swimming and during post-exercise recovery to quantify EPOC: the energy used to sustain swimming at high speeds beyond the aerobic threshold.
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George Lauder @georgelauder.bsky.social · 21/02/2024
Do #fish swimming in a #school actually save energy? A🧵on this as our paper in @eLife elifesciences.org/articles/90352 by @TheYangfanZHANG addresses this question. This is a challenging issue to study: energy use by a school should be compared to solitary locomotion
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George Lauder @georgelauder.bsky.social · 21/02/2024
Do #fish swimming in a #school actually save energy? Our paper on this in eLife elifesciences.org/articles/90352 addresses this question. This is a challenging issue: energy use by a school needs to be compared to solitary locomotion on a per gram basis under the same swimming conditions.
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George Lauder @georgelauder.bsky.social · 02/01/2024
The shark #denticle #multiverse will be on display at #sicb2024 this week. See talks in the @SICB_DCB_DVM sessions. So much diversity, so little time ... below the #ontogeny of sleeper shark denticles from Vaz et al. 2023: mdpi.com/1424-2818/15...
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George Lauder @georgelauder.bsky.social · 02/01/2024
The shark #denticle #multiverse will be on display at #sicb2024 this week. See talks in the @SICB_DCB_DVM sessions. So much diversity, so little time ... below the #ontogeny of sleeper shark denticles from Vaz et al. 2023: www.mdpi.com/1424-2818/15/11/1105
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George Lauder @georgelauder.bsky.social · 02/01/2024
Getting ready for #SICB2024, and all things #shark skin! Testing patches of skin to measure the shear stress (friction) of water moving over the skin, and how #denticle orientation alters flow patterns.
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George Lauder @georgelauder.bsky.social · 02/01/2024
Getting ready for #SICB2024, and all things #shark skin! Testing patches of skin to measure the shear stress (friction) of water moving over the skin, and how #denticle orientation alters flow patterns.
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George Lauder @georgelauder.bsky.social · 24/03/2023
We showed that fish tune their tail beat to the foil, intercept vortices, slightly alter body motion, and tune phase based on their distance from the foil. Due to how the head intercepts the foil wake we propose that fish can reduce swimming costs even in a thrust wake.
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George Lauder @georgelauder.bsky.social · 24/03/2023
@rthandiackal and I conducted experiments to simplify the in-line swimming condition and allow a fish to swim in a thrust wake generated by a flapping foil (the @eLife link makes it easy to see the videos embedded into the main text): elifesciences.org/articles/81392
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George Lauder @georgelauder.bsky.social · 24/03/2023
The difference between fish swimming in reduced flow (a drag wake) and in-line (with a thrust wake impacting the following fish) is nicely summarized by the graphic below from the commentary by @icouzin and Liang Li in @eLife: elifesciences.org/articles/86807
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George Lauder @georgelauder.bsky.social · 24/03/2023
Why might #fish in a #school swim behind one another? A🧵.This question arises because being behind another fish involves #swimming in faster flow. A cyclist can draft because oncoming velocity is reduced. A thrust wake is like a cyclist facing a leader with a large fan.
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George Lauder @georgelauder.bsky.social · 02/01/2023
The #shark #denticle #multiverse is vast, and @MarBioMoll will present at #SICB2023 on ontogenetic changes in skin denticles in leopard sharks. So much variation and so few previous studies of denticle ontogeny @SICB_ @SICB_DCB_DVM
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George Lauder @georgelauder.bsky.social · 02/01/2023
Gearing up for the #SICB2023 meetings … first up is the #shark #denticle #multiverse! Talks by @dfbvaz and Tess Avery will describe remarkable changes in denticles during ontogeny in the Portuguese dogfish, accompanied by lots of variation around the body @SICB_ @SICB_DCB_DVM
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George Lauder @georgelauder.bsky.social · 17/06/2022
There are many methods that comparative biologists can use to understand the diversity of life: let’s make robotics one of them!
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George Lauder @georgelauder.bsky.social · 17/06/2022
The performance landscape for any behavior can be complex with more than one peak. Here’s one for swimming … it has two peaks! How would we determine this studying living species alone, without the ability to alter all experimental parameters to generate the surface?
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George Lauder @georgelauder.bsky.social · 17/06/2022
Designing a robotic mechanism where we can vary individual traits on demand avoids the challenge of uncontrolled variables. A robotic fish allows us to identify the effect of specific changes that would be impossible to study in a living fish: bit.ly/3mXyJz7
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George Lauder @georgelauder.bsky.social · 17/06/2022
When making comparisons among organisms it is extremely challenging to isolate only the trait of interest. We could compare the function of a tuna and sunfish tail, but these two fish species differ in countless other traits.
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George Lauder @georgelauder.bsky.social · 11/02/2022
We developed a special filming setup for kinematics and hydrodynamics so as not to kill the heart cells. Swimming performance of the biohybrid fish in the nutrient solution improved for the first 30 days and then was sustained for 108 days!
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George Lauder @georgelauder.bsky.social · 11/02/2022
This biohybrid fish demonstrates by far the fastest directed movements of any such system to date, and shows the importance of antagonistic muscular design to move the body. This is hard to achieve!
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George Lauder @georgelauder.bsky.social · 11/02/2022
Why heart cells? Cardiac cells are perfect because they are electrically connected and produce a wave of activity and body bending to power swimming, and they are stretch-activated so that body bending on one side stimulates contraction on the other side … closed-loop behavior!
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George Lauder @georgelauder.bsky.social · 11/02/2022
Very happy to have been part of the large team led by the amazing Gilyong Lee (in Kit Parker’s lab @Harvard) and Prof. Sung Jin Park (@GeorgiaTech) including work on the biohybrid fish kinematics and hydrodynamics by grad student Dave Matthews (@Orang_Hutan_ )
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George Lauder @georgelauder.bsky.social · 11/02/2022
A small robotic fish powered by human heart cells??!! A thread on biohybrid robots to celebrate the large collaborative effort just out in Science (bit.ly/3Jj13VS)
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George Lauder @georgelauder.bsky.social · 11/01/2022
Can robotic systems improve swimming by tuning body stiffness as speed increases? Yes! Tuna-inspired robotic platforms show that altering body stiffness during faster swimming allows energetic economy to be maintained.
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George Lauder @georgelauder.bsky.social · 11/01/2022
Fish alter body stiffness via antagonistic muscle activity but experimental evidence from freely-swimming fishes showing active tuning of stiffness as swimming speed changes is still lacking.
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George Lauder @georgelauder.bsky.social · 11/01/2022
Dan Quinn @UVA and I review mechanisms that both fish and robots use to tune their body stiffness in a new paper in @BioinspBiomim (bit.ly/3qhb0wf).
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George Lauder @georgelauder.bsky.social · 11/01/2022
Most fish have very flexible bodies as seen here in an anesthetized trout. But how stiff should fish be to swim effectively, and how can fish (and robots) modulate their body stiffness to improve swimming performance? – a thread.
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George Lauder @georgelauder.bsky.social · 04/01/2022
Much this goes back to Dick Lewontin’s famous paper on adaptation where he makes it clear that a major issue in comparative biology is frequent violation of the ceteris paribus assumption: that organisms can be compared assuming that all else is equal.
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George Lauder @georgelauder.bsky.social · 04/01/2022
Quantifying the performance landscape in particular is extremely challenging in living organisms. Here’s a swimming performance surface from work that Dan Quinn, Lex Smits, and I did (bit.ly/3qNZK9N): It has two peaks!
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George Lauder @georgelauder.bsky.social · 04/01/2022
Why should robotics be part of our toolkit? Robotic systems allow: (1) Precise control so that only the trait of interest can be varied; (2) Quantification of the performance landscape; (3) Direct measurement of energetic cost.
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George Lauder @georgelauder.bsky.social · 04/01/2022
When we make comparisons among organisms to examine the role of one specific feature, it is extremely challenging to isolate only the trait of interest. Who would want to compare the function of the tail in these two species, assuming that all else is equal?
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George Lauder @georgelauder.bsky.social · 04/01/2022
What role can #robotics play in #ecology and evolutionary biology? – a thread. My talk at #SICB2022 has the goal of discussing why and how I think that robotics should be thought of as a “comparative method” @SICB_DCB_DVM.
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George Lauder @georgelauder.bsky.social · 30/12/2021
Hence the need for dynamic testing of shark skin either in live sharks or 3D prints attached to a swimming robotic system (movie below). Experiments show that the shark skin surface both reduces drag AND increases thrust. Denticles are not just about drag reduction!
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George Lauder @georgelauder.bsky.social · 30/12/2021
Most engineering studies of shark denticles use static experiments, but shark skin clearly moves with the body during undulatory locomotion, a dynamic flow condition not captured by static analyses.
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George Lauder @georgelauder.bsky.social · 30/12/2021
At the @SICB_ #SICB2022 meeting Dylan Wainwright will present our experimental results on flow over branchial skin denticles in live sharks. The jet of water is visualized as each breath passes over the downstream denticles (colors show water velocity exiting the gill slits).
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George Lauder @georgelauder.bsky.social · 30/12/2021
So why is this important? A key reason: #denticles on branchial pouch skin are amenable to experimental measurement in the laboratory. We can measure flow over these denticles in live sharks to understand the relationship between denticle shape and flow.
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