Japanese scientists discovered that rats like stroking of human. To do this, they for eight weeks through the day for five minutes stroking young rats: some — all the time, others only the first or last four weeks. Rats who got used to the stroking, squeaking with a frequency of 50 kHz, when they are stroked (this vocalization is associated with pleasure) and also in the open space followed the hand of experimenter, which they are stroked. In addition, in their brain after strokes was observed increased concentration of oxytocin, write scientists in Scientific Reports.
Physical contact (e.g. grooming — cleaning combing and licking) is quite common among social animals: he, in particular, helps to establish the relationship between individuals and can even reduce stress. Slightly less common interspecific physical contact; it is often the case, the touch between people and their Pets, which can be beneficial to both sides.
In this context, however, more study of dogs and cats, but other animals who are often in contact with the person (e.g., laboratory), pay a little less attention. Tatsushi Onaka (Tatsushi Onaka) and his colleagues from the Medical University Jichi decided to focus on rats. Their experiment involved 44 males, which were divided into four groups at the age of three weeks. Over the next eight weeks, the experimenter stroked the rats arm, across his knees, within five minutes through the day, recording their sound. The first group was stroking all eight weeks, second four weeks and the third in the last four weeks. Rats from the control group were not touched at all.
At the end of eight weeks the researchers conducted several additional experiments: they watched whether the animals behind the hand that stroked, give her preference in an open space where you can come either to the hand or another object (in this experiment the bottle), as well as whether the pats rewarding stimulus for rats: in other words, will they to go from one room to another only to be petted.
Scientists have found that rats, which was stroking the last week of the experiment, and eight weeks significantly (p < 0.0001), more likely to squeak at a frequency of 50 kilohertz compared to the rats which were only ironed in the first four weeks, and rats in the control group. Such vocalization, according to scientists, is characteristic of rats suffering joy — this allowed the scientists to conclude that rats pats a person in reality like.
In addition, rats of all their experimental groups were much (p < 0.0001) more time with the hand that stroked, and not to another object, compared with the control group, for which the difference between the bottle and the hand was not. In addition, rats that were accustomed to the stroking of a man also often followed his arm (p < 0.0001).
After all behavioral experiments, the researchers took several rats from each group: one half stroked, and the second no, and then slew to analyze the expression of the transcription factor c-Fos in oxytocin immunoreactive neurons is a characteristic indicator of the activity of neurotransmitter that can be measured in brain tissue immediately after exposure to the stimulus. All rats were accustomed to the strokes, markers of the activity of oxytocin post mortem immediately after the strokes were observed more than in the control rats (p = 0.03).
The authors concluded that rats can exhibit affiliative behavior in relation to the person if they are accustomed to the strokes. From strokes, in turn, in the brain of rats increases concentarte oxytocin — peptide hormone and neurotransmitter that is responsible for building and maintaining social ties.
In General, the man and the rat can communicate with each other quite closely — and even play: for example, in September last year, neuroscientists have been able to teach rodents to play hide and seek with them.