Striking differences in brain morphology between wild and domestic rabbits

Striking differences in brain morphology between wild and domestic rabbits
Illustration of striking phenotypic differences between domestic and wild rabbits including changes in the size of the amygdala and the medial prefrontal cortex. Credit: Fabian Sinzinger

The most characteristic feature of domestic animals is tame behaviour. An international team of scientists has now used high-resolution magnetic resonance imaging (MRI) to study how domestication affects brain morphology in domestic rabbits. The results show that domestication has a profound effect on brain morphology in particular regions of the brain involved in fear processing, the amygdala and medial prefrontal cortex. The study is published in PNAS.

In contrast to domestic rabbits, wild rabbits have a very strong flight response because they are hunted by eagles, hawks, foxes and humans, and therefore must be very alert and reactive to survive in the wild. In fact, Charles Darwin wrote in On the Origin of Species that " animal is more difficult to tame than the young of the wild rabbit; scarcely any animal is tamer than the young of the tame ." There is no doubt that these differences in behaviour between wild and domestic animals to a large extent are genetically determined.

"In a previous study we reported that genetic differences between wild and domestic rabbits are particularly common in the vicinity of genes expressed during brain development," explains Miguel Carneiro, from CIBIO-InBIO, University of Porto, one of the leading authors on the paper. "In the present study, we decided to use high-resolution MRI to explore if these genetic changes are associated with changes in brain morphology," says Miguel Carneiro.

The scientists raised eight domestic and eight wild rabbits under very similar conditions to minimize changes due to environmental effects. Furthermore, the brain MRI data were interpreted with sophisticated image analysis in which the scientist carrying out the analysis was unaware of the status (wild or domestic).

Striking differences in brain morphology between wild and domestic rabbits
Madonna of the rabbit, painted 1530 by Tiziano Vecellio, The Louvre, Paris. A painting illustrating a domestic rabbit from the 16th century with altered coat color and behavior compared with a wild rabbit. Credit: UM SEGUNDO FILMES/CIBIO, Porto, Portugal.

"We observed three profound differences between the brains of wild and domestic rabbits," says Irene Brusini, first author and Ph.D. student at KTH Royal Institute of Technology in Stockholm. "Firstly, wild rabbits have a larger brain-to-body size ratio than domestic rabbits. Secondly, domestic rabbits have a reduced amygdala and an enlarged . Thirdly, we noticed a generalized reduction in white matter structure in domestic rabbits."

"These differences in brain morphology make perfect sense in relation to the fact that domestic rabbits are less fearful and have an attenuated flight response compared with wild rabbits," explains Mats Fredrikson, Professor at Uppsala University and Karolinska Institutet, one of the senior authors on the paper. "Our results show that an area involved in sensing fear (the amygdala) is smaller in size while an area controlling the response to fear (the medial prefrontal cortex) is larger in domestic rabbits. The reduced amount of white matter suggests that domestic rabbits have a compromised information processing possibly explaining why they are more slow reacting and phlegmatic than their wild counterparts."

"No previous study on animal domestication has explored changes in brain morphology between wild and in such depth as we have done in this study," says Leif Andersson, Uppsala University, Swedish University of Agricultural Sciences and Texas A&M University. "When we initiated the study the concern was that any changes may be too subtle to be noticeable with MRI but that was clearly not the case as we noticed distinct changes. This study is not only important for our understanding of animal domestication but also for the basic understanding how variation in can impact a complex behaviour like fear response," says Leif Andersson.

Explore further

New study reveals how wild rabbits were genetically transformed into tame rabbits

More information: Irene Brusini el al., "Changes in brain architecture are consistent with altered fear processing in domestic rabbits," PNAS (2018).
Provided by Uppsala University
Citation: Striking differences in brain morphology between wild and domestic rabbits (2018, June 26) retrieved 18 July 2019 from
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Jun 26, 2018
"The domestication (the culture) of man does not go deep--where it does go deep it at once becomes degeneration (type: the Christian). The 'savage' (or, in moral terms, the evil man) is a return to nature--and in a certain sense his recovery, his cure from 'culture'." 

Fredrick Nietzsche

Jun 26, 2018
mqr, You might want to consider at what stage of degenerative Syphilis damage to his brain he was suffering, when Nietzsche wrote that racist screed. And how brain dead the incompetent translator. Who bungled the High German to Low English.

It would be interesting to see this same research performed on domesticated reindeer. To compare against the large population of wild reindeer.

Which may be an example of possibly similar processes during the domestication of equines and bovines and camelidae.

Jun 26, 2018
Yes I do consider that Nietzsche said wild things, and I suspect too that his brain was damaged.

But I do consider that his general view of Christianity to have valid points. Especially regarding that Eastern religions were directed towards spiritual perfection while Christians to the day keep saying that they can do whatever they want because Jesus was murdered in the cross, and somehow they interpret his death as freedom to engage in vile actions.

The other point that I mentioned above is that Western society, being strongly based on Christian ideas, is very anti intellectual and self destructive, especially is destructive towards masculinity, towards power, as Nietzsche said it, against most things that allow development and growth. Metrosexuals are a direct consequence of Christianity.

Jun 26, 2018
Syphilis to his brain he was suffering
"Friedrich Nietzsche, the philosopher thought to have died of syphilis caught from prostitutes, was in fact the victim of a posthumous smear campaign by anti-Nazis, according to new research.

"A study of medical records has found that, far from suffering a sexually-transmitted disease which drove him mad, Nietzsche almost certainly died of brain cancer."

-Hey willis have you considered that the impetus for many of your idiot ideas might be simple ignorance? It is obvious you have a preference for smear campains over facts, evidence, and truth. Tickles your fancy I suppose.

This is the place to confront your deficits and debilities.

Jun 26, 2018
Oh otto, your leadership as a prima facie examplar of crazy ignorance is such an inspiration for all of cranks who aspire to your pretentious claim to being asshattery el primo.

Jun 28, 2018
Wow otto, you are certainly a lot more "certain" than the researchers you are quoting. For the curious here is the site otto accessed & another research team with similar conclusions.
Why I am skeptical of their findings? Is the researchers reliance on Nietzsche written letters as evidence. Yet by 1880 he was going blind and a secretary was transcribing his illegible scribblings.

This wikipedia article accepts the syphilis diagnosis.

If it was possible to disprove FN's own doctors diagnosis? That he had an asymptomatic variety of the disease.

Then the evidence leads to the conclusion he suffered a life-long a genetic brain disability. Inherited from his father.
Friedrich Nietzsche endured a variety of severe injuries & diseases. Finally deteriorating into crippling insanity.

Jun 28, 2018
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Jun 29, 2018
Yes ZB, prepubescent animals including humans enjoy playing.

Then when the puberty hormones kick-in? They all go apeshit crazy!

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