Do goats exhibit prosocial motivation? Insights from a novel food-giving paradigm

Abstract

Research on prosociality in animals has largely focused on a few model species and a limited range of experimental paradigms. To expand this scope, we developed an ecologically relevant food-giving paradigm, the Fake Apple Tree, designed to assess prosocial motivation in goats (Capra hircus) by stimulating their natural climbing behaviour. In this set-up, when a 'donor' goat stepped onto a platform attached to a pivoting arm, the arm lowered a food dispenser within reach of conspecific 'recipients', while the donor itself could not access the reward. Ten out of twelve goats spontaneously learned to operate the device. In dyadic trials, goats interacted with the Fake Apple Tree more frequently when the food dispenser was active compared to control sessions where no food was provided. The frequency of interactions remained stable across test sessions. We classified platform interactions as prosocial if the donor left without approaching the food dispenser and selfish if it attempted to access the food afterwards. Consistent with findings in primates, prosocial interactions were significantly longer than selfish ones. Our results provide insights into potential prosocial tendencies in goats and highlight the utility of ecologically relevant paradigms in studying cooperative behaviours in ungulates.

Keywords: Fake Apple Tree; altruism; cognition; farm animals; prosociality; ungulates.

Figure 1.

Left image: the test arena with the Fake Apple Tree apparatus on which the platform (a) and dispenser (b) were attached. Right image: the dispenser, containing raw pasta, attached to the pivoting arm.

Figure 2.

The test arena with the testing apparatus and the three different zones for observation: platform zone coloured in red, dispenser zone coloured in blue and other zone in yellow.

Figure 3.

(A) Total number of platform interactions of 10 individuals across all three sessions, divided into ‘selfish’ and ‘prosocial’ interactions. (B) Estimated probability of selfish motivation. Animals with values <0.5 are regarded as prosocial animals, and animals with values >0.5 are regarded as selfish animals. Presented are EMMs with 95% confidence intervals of a binomial GLMM.

Figure 4.

Number of platform interactions per session per individual (log-transformed) in all three sessions (control, test 1, test 2). Boxes show the interquartile range (25th percentile to 75th percentile) and median. The variability outside the upper and lower quartiles (up to 1.5 times the interquartile range) is depicted by the whiskers. Points represent the sum of platform interactions of an individual per session.

Figure 5.

Duration (log-transformed) of platform interactions, divided into selfish and prosocial acts. Boxes show the interquartile range (25th percentile to 75th percentile) and median. The variability outside the upper and lower quartiles (up to 1.5 times the interquartile range) is depicted by the whiskers. Points represent the duration of individual platform interactions.