Domestic pigs are quite social animals and if they grunt, they would like to say something like, that they care about the offspring. Or they call for the other pigs while foraging. And they squeak when they are scared or uncomfortable. "The sounds they make convey a lot of information about the animal's emotional, physical, and motivational state, " explains Lisa Collins of the University of Lincoln. Together with Mary Friel from Queens University in Belfast she wanted to know if the well-being of Sus scrofa domestica can be read by his grunts. Especially in terms of the environment in which the animals grow up.
Desolate environment makes restless
Because depending on the environment, pigs develop a different personality, explain Collins and Friel. If the omnivores die their existence in a desolate and poorly adapted stable, they tend to behave restlessly and aimlessly. If, on the other hand, they live in a cage with sufficient "enrichment", ie type-typical employment opportunities for wallowing, rooting or scratching, the animals show no behavioral problems, the researchers say.
For their study, the researchers distributed a total of 72 young pigs, including 38 male and 34 female, to two different types of pigs. One group was allowed to wallow in a straw bedded stable, the other was housed in a cage with grid floor. Now the researchers each led an animal from both types of stable into a room with concrete floor and left the pig for a few minutes themselves. Then it came into a room with a bucket and a traffic cone, with which the animals could deal. During the experiments, the scientists recorded the sounds of the animals, more precisely how and how often the pigs grunted.
Male pigs are more susceptible
Collins and Friel first noticed that the pigs from the straw boxes in the concrete rooms were much more agile. They spent less time exploring the new environment and turned to the toy faster. At the same time, they emitted more grunts than the animals from the grid floor. These roamed the concrete room for a longer time and were hardly interested in buckets or traffic cones. The researchers repeated the tests after two weeks to see if the pigs continued to behave the same way in the "isolation custody" and reveal certain personality patterns - which was the case in the end. display
However, the animals did not only differ according to which colony they grew up in, but also according to their gender. Because the male pigs showed particularly clear differences in the Grunz frequency. The sows, on the other hand, could hardly be impressed by their surroundings in the long term. "This suggests that male pigs respond differently to chronic stress than females, " the researchers conclude. They are therefore more sensitive to their environment than their female counterparts. Ultimately, therefore, the well-being of the pigs can be read off the lute - if one knows how to understand them.
- Mary Friel et al., Acoustic signaling re fl ects personality in a social mammal, Royal Society Open Science 2016, 3: 160178