What if the brains of birds and mammals weren’t as similar as we assumed? For years, scientists believed these animals shared a blueprint for developing complex brain circuits. Surprisingly, researchers from the Achucarro Basque Center for Neuroscience in Spain and Heidelberg University in Germany reveal an entirely different story: birds and mammals evolved their advanced brain circuits independently, using different genetic mechanisms.
The research, led by Dr. Fernando García-Moreno and a global team of scientists, challenges the traditional belief that bird and mammal brains evolved in the same way. While their brains perform similar tasks, the new studies reveal that the genetic and cellular processes behind these functions are remarkably different.
Dr. García-Moreno, head of the Brain Development and Evolution laboratory at the Achucarro Basque Center for Neuroscience, explains, “Birds have developed sophisticated neural circuits through their own mechanisms, without following the same path as mammals. This changes how we understand brain evolution.” The research focused on the pallium—a brain region responsible for complex thought and sensory processing.
In mammals, this area forms the neocortex, the part of the brain that allows for higher-order thinking. Scientists previously believed that birds, reptiles, and mammals shared a common template for building this region. However, the new studies reveal a surprising twist: while the brain circuits function similarly, their building process during embryonic development varies drastically between species.
The first study, led by Dr. García-Moreno and Eneritz Rueda-Alaña, shows that bird and mammal neurons—the brain’s information messengers—are born in different places and at different times during development. Using advanced genetic techniques and mathematical modeling, the team found that birds and mammals use different genetic instructions to form brain circuits.
“The genetic tools they use to establish their cellular identity vary from species to species, each exhibiting new and unique cell types,” says Dr. García-Moreno. This suggests that these brain structures didn’t evolve from a single ancestor. Instead, they arose independently through convergent evolution, the process by which unrelated species evolve similar traits independently— that is, different species find their own way to solve the same problem.
The second study, led by Bastienne Zaremba and Henrik Kaessmann at Heidelberg University, dug even deeper. By analyzing individual brain cells in birds, mammals, and reptiles, the team built a detailed map of their neuronal diversity. They found that while inhibitory neurons—the cells that slow down brain activity—are ancient and shared across species, most excitatory neurons, which transmit signals, have evolved uniquely in each group. Only a small handful of neuron types, such as those in the hippocampus (important for memory) and claustrum (linked to attention), remain similar across species.
These discoveries change how scientists understand brain evolution. They reveal that there is no single path to developing intelligence—nature has found multiple ways to build complex, thinking brains. For decades, scientists thought that studying one species could explain brain function across all vertebrates. These findings suggest it’s not that simple—brains can evolve using different genetic blueprints, yet still perform similar tasks.
The research opens exciting new possibilities for neuroscience. By studying how different species build their brains, scientists may one day uncover new treatments for brain-related conditions, or even design bio-inspired technologies that mimic natural intelligence.
So, the next time you see a bird in flight or a mammal solving a puzzle, remember—they each got their mind through very different evolutionary journeys, proving that when it comes to building a complex brain, the mechanism is also complex.
For more details, you can refer to the first and second research articles that are published in Science.
Copyright @smorescience. All rights reserved. Do not copy, cite, publish, or distribute this content without permission.
