Aggression, Boldness, and Exploration Personality Traits in the Subterranean Naked Mole-Rat (Heterocephalus glaber) Disperser Morphs

SIMPLE SUMMARY: Naked mole-rats have a unique social system similar to insects, where there is one reproductive female, one to three reproductive males, and the rest are non-reproductive members of the colony. Within the non-reproductive members, there are dispersers that attempt to leave the colony. We aimed to investigate if naked mole-rat dispersers have consistent behavioral responses to situations and therefore possess animal personality traits. The naked mole-rat dispersers showed consistent responses to different situations, and had consistent differences between individuals. In addition, we recorded how naked mole-rats respond to situations that threaten their survival, such as a new environment and predators. Further investigation into these animal personality traits and how they compare between other colony members, such as workers and soldiers are needed to understand the naked mole-rat social system. ABSTRACT: Animal personality traits (consistent behavioral differences between individuals in their behavior across time and/or situation) affect individual fitness through facets, such as dispersal. In eusocial naked mole-rat (Heterocephalus glaber) colonies, a disperser morph may arise with distinct morphological, behavioral, and physiological characteristics. This study aimed to quantify the personality traits of a cohort of disperser morphs of naked mole-rat (NMR). Behavioral tests were performed on twelve disperser morphs (six males and six females) in an observation tunnel system that was novel and unfamiliar. Novel stimuli (fresh snakeskin, tissue paper, and conspecific of the same sex) were introduced for fifteen minutes, and the behavioral acts of the individual were recorded. A total of 30 behaviors were noted during the behavioral tests of which eight were used to quantify aggression, boldness, and exploration. The NMR disperser morphs showed consistent individual differences in boldness, and exploration across time and test, indicating a distinct personality. In addition, new naked mole-rat responses including disturbance behaviors; confront, barricade, and stay-away, were recorded. Further investigations into the relationships between animal personality traits and social hierarchy position in entire colonies are needed for more informative results as we further investigate the role of personality in cooperatively breeding societies.