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Felix Baier

@felixbaier.bsky.social

Natural behavior, brain evolution, & ecological change, with a focus on wild 🐭 and 🦎. Currently a Postdoc @mpibrain.bsky.social‬; PhD from @harvardmcb.bsky.social‬. he/him felixbaier.github.io

308 Followers  |  264 Following  |  13 Posts  |  Joined: 21.12.2024
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Posts by Felix Baier (@felixbaier.bsky.social)

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Agouti integrates environmental cues to regulate paternal behaviour - Nature Expression of agouti signalling protein in neurons in the medial preoptic area is increased by group housing and negatively associated with care, and overexpression of Agouti reduces care and enhances...

Why are some males caring toward infants while others are neglectful or abusive? I'm so pleased to share work that my colleagues and I @princeton.edu have just published @nature.com (an explanatory thread to follow!) (1/8)

18.02.2026 17:05 β€” πŸ‘ 139    πŸ” 58    πŸ’¬ 9    πŸ“Œ 6
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Predatory aggression evolved through adaptations to noradrenergic circuits - Nature Noradrenergic circuits support and balance aggressive behavioural states in predatory nematodes, distinguish predatory from non-predatory nematode species and are associated with the evolution of comp...

Why do some worms graze on bacteria while others hunt and kill?
Our study, published today in Nature, reveals how predatory aggression evolved in nematodes.
Led by @gunizgozeeren.bsky.social and @leoboeger.bsky.social across the @jameslightfoot.bsky.social and @monikakscholz.bsky.social labs.

21.01.2026 16:31 β€” πŸ‘ 80    πŸ” 35    πŸ’¬ 9    πŸ“Œ 5

I’m excited to share my PhD work on localized mRNAs and protein synthesis in cortical layer 1 on bioRxiv! www.biorxiv.org/content/10.1...

25.11.2025 16:58 β€” πŸ‘ 15    πŸ” 6    πŸ’¬ 1    πŸ“Œ 0

As a longtime fan of cool papers in @currentbiology.bsky.social, I am really thrilled to see this out!

This study sets the stage for understanding the origins of novel (vocal) behaviors.

Big shout out to the main architects of this work @xmikezheng20.bsky.social and @cliffscience.bsky.social

19.11.2025 18:42 β€” πŸ‘ 56    πŸ” 23    πŸ’¬ 8    πŸ“Œ 1
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Ancient origin of an urban underground mosquito Understanding how life is adapting to urban environments represents an important challenge in evolutionary biology. In this work, we investigate a widely cited example of urban adaptation, Culex pipie...

How does life evolve to adapt to modern cities?

Out now in Science, my PhD work with @lindymcbr.bsky.social uncovers the ancient origin of the β€œLondon Underground mosquito” – one of the most iconic examples of urban adaptation.

🧡(1/n)
@science.org
www.science.org/doi/10.1126/science.ady4515

25.10.2025 04:45 β€” πŸ‘ 251    πŸ” 101    πŸ’¬ 8    πŸ“Œ 8

Amazing, congrats Kelsey!

22.10.2025 21:26 β€” πŸ‘ 2    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0

🧠🌟🐭 Excited to share some of my postdoc work on the evolution of dexterity!

We compared deer mice evolved in forest vs prairie habitats. We found that forest mice have:
(1) more corticospinal neurons (CSNs)
(2) better hand dexterity
(3) more dexterous climbing, which is linked to CSN number🧡

22.10.2025 20:41 β€” πŸ‘ 378    πŸ” 124    πŸ’¬ 19    πŸ“Œ 26
a group of Drosophila erecta fruit flies on a small food patch. flies on white background

a group of Drosophila erecta fruit flies on a small food patch. flies on white background

Excited to share our new #biorxivpreprint

We discovered that the fruit fly #drosophila erecta requires food odor to mate and arousal is further enhanced by social group motion.

Cross-species analysis of brain activity reveals a novel gate evolved from within a conserved circuit

shorturl.at/gGYm7

16.10.2025 06:33 β€” πŸ‘ 83    πŸ” 44    πŸ’¬ 12    πŸ“Œ 3
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Family-based selection: an efficient method for increasing phenotypic variability This article introduces a model comparing various selection regimes for increasing phenotypic variability. Individuals with the same genotype, reared in id

Our new study modeling selection for (behavioral) variability has been covered in a lovely @genetics-gsa.bsky.social podcast featuring first author Shraddha Lall and @ecoevogal.bsky.social

academic.oup.com/g3journal/ad...

08.10.2025 16:26 β€” πŸ‘ 40    πŸ” 16    πŸ’¬ 5    πŸ“Œ 0
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🚨Hiring Alert! Join Gregor Schuhknechts’s
new group Brain Algorithms and Circuits @mpibrain.bsky.social !

🧠 Fully funded PhD & Postdoc
🐟 Larval #zebrafish model
πŸ”¬ Imaging, electrophysiology, EM
πŸ’» #SystemsNeuroscience

πŸ‘‰ brain.mpg.de/schuhknecht

01.08.2025 13:49 β€” πŸ‘ 3    πŸ” 4    πŸ’¬ 0    πŸ“Œ 0
Postdoctoral Position (f/m/d) at the Chair of Behavioral Physiology & Sociobiology Biocenter of the University of WΓΌrzburg Am Hubland 97074 WΓΌrzburg

We are looking for a Postdoc (up to 5 years) who wants to study neural mechanisms of spatial memory in honeybees.

This includes tetrode recordings in behaving honeybees.

Application Deadline is 1st of October 2025.

More details:
www.biozentrum.uni-wuerzburg.de/en/services/...

01.08.2025 08:44 β€” πŸ‘ 49    πŸ” 42    πŸ’¬ 1    πŸ“Œ 5

Thanks Ivan, and congrats on your amazing work!

31.07.2025 09:01 β€” πŸ‘ 0    πŸ” 0    πŸ’¬ 0    πŸ“Œ 0
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A hypothalamic circuit that modulates feeding and parenting behaviours - Nature Single-cell transcriptomic analysis of mouse hypothalamus and behavioural experiments show that specific hypothalamic networks regulate conflicting feeding versus parenting behaviours of female mice.

How do animals decide if they should forage for food or stay home to take care of newborn offspring? Whose needs come first? For my PhD work now out in Nature, we examined how hunger and parenting neurons interact and are reshaped postpartum in mice πŸ§΅β¬‡οΈ www.nature.com/articles/s41...

30.07.2025 16:35 β€” πŸ‘ 179    πŸ” 50    πŸ’¬ 14    πŸ“Œ 3
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Computational Urban Ecology of New York City Rats Urban rats are highly adaptable, thriving in the dynamic and often inhospitable conditions of modern cities. Despite substantial mitigation efforts, they remain an enduring presence in urban environme...

New preprint!



tl;dr β€” We ran around late at night to record wild rats in NYC and figured out how to quantify their behavior and environment. 🧡

w/ Dima Batenkov, @zamakany.bsky.social, Emily Mackevicius

www.biorxiv.org/content/10.1...

25.07.2025 15:57 β€” πŸ‘ 135    πŸ” 47    πŸ’¬ 6    πŸ“Œ 4

🧡8/8 We conclude that evolution adjusted the role of the dPAG in the computation of escape, thereby raising the escape threshold in P. polionotus.

Special thanks to co-first Katja Reinhard and co-last Karl Farrow for superb collab, to @hhmi.org for πŸ’°, and to the 🐭 for holding fascinating insights πŸ₯³

23.07.2025 15:05 β€” πŸ‘ 10    πŸ” 0    πŸ’¬ 4    πŸ“Œ 0
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🧡7/8 When referees requested loss-of-function expts, @arnausd.bsky.social and Chen Liu jumped in and carried us to the finish line.

They found that chemogenetic inhibition of dPAG during looming delays escape onset in P. maniculatus, such that the species appear almost identical!

23.07.2025 15:05 β€” πŸ‘ 5    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0
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🧡6/8 To test for a causal role of the dPAG, I joined Katja in Belgium, and with help from undergrad Julie Murmann, we set up optogenetics in these wild mice.

Remarkably, dPAG activation alone triggered similar species differences - suggesting sufficiency of this brain region for the behavior.

23.07.2025 15:05 β€” πŸ‘ 5    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0
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🧡5/8 To dissect further, we shipped mice to Belgium and teamed up with the @farrowlab.bsky.social: @katjareinhard.bsky.social, now w/ her own lab, figured out how to record from escaping mice - and with @bramnuttin.bsky.social, found that dPAG neurons in the two species encode behavior differently.

23.07.2025 15:05 β€” πŸ‘ 6    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0
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🧡4/8 Indeed, by staining for FOS in mice exposed to visual threat, we found that retinorecipient superior colliculus is activated in both species.

However, the periaqueductal gray (dPAG), known for its role in escape, was activated much less in P. polionotus, even when they strongly escaped!

23.07.2025 15:05 β€” πŸ‘ 7    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0
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🧡3/8 We were curious: where did evolution act in the brain to adjust behavior?

To narrow down our search, we exposed mice to an auditory stimulus – and observed the same behavioral differences.

This suggested a mechanism downstream of sensory detection, relevant across modalities.

23.07.2025 15:05 β€” πŸ‘ 5    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0
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🧡2/8 Inspired by work in lab mice, Hopi and I asked how wild-derived deer mice respond to visual threat.

With help from undergrad Tori Tong, we discovered robust variation: while P. maniculatus escaped, much like Mus, sister species P. polionotus, from open habitats in Florida, briefly froze!

23.07.2025 15:05 β€” πŸ‘ 6    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0
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🚨Very happy that my PhD work is now out in @nature.com!

We discovered that evolution, by acting in the midbrain, shifted the threshold to escape in Peromyscus mice, to fine-tune defensive strategies in different environments

www.nature.com/articles/s41...

This was a truly collaborative effort! πŸ§΅β¬‡οΈ

23.07.2025 15:05 β€” πŸ‘ 473    πŸ” 103    πŸ’¬ 26    πŸ“Œ 5
Graphical abstract for "Vocal communication is seasonal in social groups of wild, free-living house mice."

The abstract has, from top to bottom, a title, four middle image panels, and two bottom text panels.

Image title: "Vocal communication in social groups of wild-free living house mice"

Middle image panels from left to right: (1) An aerial snap shot of the region where the study site is located, an agricultural landscape in rural Switzerland. (2) An image of the study site, a small barn in the forest inhabited by mice. (3) An image of a radio frequency identification (RFID) box used to track mouse social interactions. A mouse is entering the box from the left while another sits outside. (4) A spectrogram showing example vocalizations - one low frequency squeak and one ultrasonic call - recorded from an RFID box.

Bottom panels:
Left: Data CollectionΒ 
-Β 10 years of RFID-based tracking data (from 6,946 mice)
-Β 15 months of acoustic monitoring (totaling 6,594 hours)
-Β Machine learning for vocal detection and labeling (CNN)

Right: Key Findings
-Β Vocalization is seasonal (most in spring and summer)
-Β Vocalization is associated with the presence of pups
-Β Vocalization is correlated with social group dynamics

Graphical abstract for "Vocal communication is seasonal in social groups of wild, free-living house mice." The abstract has, from top to bottom, a title, four middle image panels, and two bottom text panels. Image title: "Vocal communication in social groups of wild-free living house mice" Middle image panels from left to right: (1) An aerial snap shot of the region where the study site is located, an agricultural landscape in rural Switzerland. (2) An image of the study site, a small barn in the forest inhabited by mice. (3) An image of a radio frequency identification (RFID) box used to track mouse social interactions. A mouse is entering the box from the left while another sits outside. (4) A spectrogram showing example vocalizations - one low frequency squeak and one ultrasonic call - recorded from an RFID box. Bottom panels: Left: Data CollectionΒ  -Β 10 years of RFID-based tracking data (from 6,946 mice) -Β 15 months of acoustic monitoring (totaling 6,594 hours) -Β Machine learning for vocal detection and labeling (CNN) Right: Key Findings -Β Vocalization is seasonal (most in spring and summer) -Β Vocalization is associated with the presence of pups -Β Vocalization is correlated with social group dynamics

Very happy to share the latest from my postdoc‬!

10 yrs of mouse social networks + 1.25 yrs of acoustic data ➑️ insight into vocalization & sociality in a wild population of your favorite lab model 🐁

paper: bit.ly/4n93yyD
data: bit.ly/4lfFBEk
code: bit.ly/4kNnMwx

#bioacoustics #neuroskyence

1/8

18.06.2025 18:25 β€” πŸ‘ 138    πŸ” 48    πŸ’¬ 4    πŸ“Œ 8
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The Functional and Genetic Architecture of Olfaction in Deer Mice Mammals have well-developed olfactory systems, but the molecular logic driving the extraction of biological information, how this logic evolves and contributes to differences in behavior remain unclea...

🧬 New study out: we report a chromosome-level assembly of the deer mouse Peromyscus maniculatus! A launching pad for chemosensory-evolution research. Read more πŸ‘‰ www.biorxiv.org/content/10.1...

13.05.2025 10:47 β€” πŸ‘ 16    πŸ” 7    πŸ’¬ 2    πŸ“Œ 0
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The parenting styles of deer mice Single-nuclei RNA-sequencing sheds new light on how two closely related species of deer behave differently when mating and caring for young.

A nice, layperson writeup of my latest work, which is now out on eLife!

TLDR: Using snRNA-seq, we find cell type abundance differences and sex-biased gene expression differences that may explain innate differences in mating + parenting behavior

elifesciences.org/digests/1031...

10.04.2025 14:54 β€” πŸ‘ 15    πŸ” 8    πŸ’¬ 3    πŸ“Œ 0
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Evolution of temperature preference in flies of the genus Drosophila - Nature A study using flies of the genus Drosophila adapted to life in diverse thermal environments shows how evolution has shaped temperature preference by acting on both molecular heat receptors and th...

πŸŽ‰ so excited to share my first first-author paper is out in @Nature.com, from my PhD work in the Gallio Lab! we uncover the neurobiological mechanisms that drive the evolution of temperature preference behavior in flies of the genus Drosophila πŸ‘‡

go.nature.com/4i1VQn9

06.03.2025 14:51 β€” πŸ‘ 23    πŸ” 9    πŸ’¬ 0    πŸ“Œ 1

This is a few weeks old, but LIZARDS NEVER GET OLD πŸ¦ŽπŸ˜‡ Find out what makes them so interesting in our Creature Column @naturemethods.bsky.social

12.02.2025 14:41 β€” πŸ‘ 11    πŸ” 5    πŸ’¬ 0    πŸ“Œ 0

Having flashbacks to my time in the US during Trumpβ€˜s first term. Lots of sympathy and hugs to everyone on the ground. Hang in there ❀️

05.02.2025 09:03 β€” πŸ‘ 0    πŸ” 0    πŸ’¬ 0    πŸ“Œ 0

Congrats Saikat, amazing work!!

03.02.2025 09:02 β€” πŸ‘ 2    πŸ” 0    πŸ’¬ 0    πŸ“Œ 0

SfN is thrilled to launch a new webinar series in collaboration with the @kavlifoundation.bsky.social exploring how different species’ nervous systems acclimate to environmental changes!

#NeuroSky

23.01.2025 14:59 β€” πŸ‘ 8    πŸ” 3    πŸ’¬ 1    πŸ“Œ 0