The study of animals, be they living or a long extinct species, requires a whole series of tests and experiments. Scientists have done a number of works to better understand modern animals and their evolutionary history, but recently something strange happened – a group of researchers took a small number of Nile Crocodiles (Crocodylus niloticus) under MRI scanners and played classical music by Johann Sebastian Bach
Although playing music for a cold-blooded reptile may sound very strange and dangerous, the international group is performing this daring task to better understand reptilian brains and how to respond to various complex sounds. 
Today ancient fossils help us to understand the evolution of mammals and birds, but when it comes to looking specifically at their brains there is not enough evidence to study. That is, we can not tell how the brains functioned and changed over millions of years. However, crocodiles, which are among the oldest species of vertebrates, could give some answers. The animals represent a crucial link between the age of dinosaurs and today's birds and have barely changed in the last 200 million years.
"Analyzes of crocodile brains thus provide deep insights into the evolution of the mammalian nervous system and can help us understand where specific brain structures and related behaviors have arisen," said Felix Ströckens, the lead researcher behind the work.
The group took five small, young crocodiles to a functional MRI or fMRI scanner – commonly used for clinical diagnosis and research – and played classical music to see how their brains responded. The task was not easy and required a whole series of modifications.
"We had to overcome some technical obstacles," said research team Mehdi Behroozi in the statement. "For example, we had to adapt the scanner to the physiology of the crocodile, which differs massively from mammals in several ways."
The analysis of neural activity as classical music – with rapid amplitude changes and broad frequencies – was played The researchers found that additional areas of the animal's brain were activated by complex sound, which was not the case with simple sounds. More importantly, these patterns of neural activity closely match those of mammals and birds that were part of other similar studies.
As a result, the group believes that the neural mechanisms for processing sensory stimuli may have evolved in an early evolution Stage and tracked back in all vertebrates
"As birds themselves produce quite sophisticated & # 39; music & # 39; "It can be assumed that they have special brain areas for processing complex sounds, but we did not expect crocodiles to have areas that look and work that much," Ströckens told CNET. In addition, the latest work also shows a technical breakthrough and proves that non-invasive MRI scanning technology can provide a reliable method of researching cold-blooded reptiles has never been done in the past. It could also help scientists study species that have not been thoroughly studied.
The study entitled "Functional MRI in the Nile Crocodile: A New Path for Evolutionary Neurobiology" was published on April 25 in the journal Proceedings of the Royal Society B: Biological Sciences.