How domestication can change animals' facial features

Date: April 10, 2017

Source: Universitaet Tübingen

Domesticated animals, compared to their wild counterparts, have undergone numerous changes in physiology, behavior and morphology. These changes are commonly referred to as the domestication syndrome and include behavioral changes, such as increased docility as well as genetic alterations in size, color and facial characteristics. In attempting to find whether these changes have a single cause, Russian zoologist Dmitry Belyaev conducted a series of selection experiments with silver foxes, hypothesizing that behavior, specifically tameness, was the key driving factor behind the changes brought about by domestication. After generations of selecting foxes for tameness, they were found to display phenotypes similar to those observed in domesticated species. Since then, it has been further hypothesized that selection for social tolerance and reduced aggression may also have played an important role in shaping the modern human anatomy, which is remarkable for the reduced face and gracile overall features.

In parallel to his fox experiment, Belyaev also selected rats over 64 generations for their behavior: either tameness or defensive aggression towards humans. In the first ever quantitative study on the facial anatomy of Belyaev's selected rats, an international team of researchers from the Senckenberg Center for Human Evolution and Paleoenvironment at the University of Tübingen and Pennsylvania State University collected 3-D measurements on the skulls of both tame- and aggressive-selected rats, in order to evaluate Belyaev's hypothesis that tame behavior correlates with the facial changes similar to those seen in domesticated animals. The study found that rats selected for tame behavior show some -- though not all -- traits present in domesticated animals and the tame silver foxes. The findings are published in the latest Plos One.

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Dogs Recognize Familiar Faces from Images

Dec. 18, 2013 — So far the specialized skill for recognizing facial features holistically has been assumed to be a quality that only humans and possibly primates possess. Although it's well known, that faces and eye contact play an important role in the communication between dogs and humans, this was the first study, where facial recognition of dogs was investigated with eye movement tracking.

Main focus on spontaneous behavior of dogs

Typically animals' ability to discriminate different individuals has been studied by training the animals to discriminate photographs of familiar and strange individuals. The researchers, led by Professor Outi Vainio at the University of Helsinki, tested dogs' spontaneous behavior towards images -- if the dogs are not trained to recognize faces are they able to see faces in the images and do they naturally look at familiar and strange faces differently?

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