Can animal personalities save human lives? Evidence for repeatable differences in activity and anxiety in African giant pouched rats (Cricetomys ansorgei)

Abstract

Scent-detection animals require an exceptional sense of smell as well as a unique set of behavioural traits. Regardless of species, there are specific characteristics that influence the animal's success in a detection career. However, few studies have tested these characteristics in species other than dogs (Canis lupus familiaris). APOPO, a global non-profit organisation based in Tanzania, trains giant African pouched rats (Cricetomys ansorgei) to save human lives by leveraging their olfactory abilities. The rats can detect explosives in post-conflict zones and serve as a second-line screening tool to sniff out tuberculosis (TB) in human sputum samples. The rats' scent-detection behaviours are influenced by a myriad of external (e.g., scent training) and internal (e.g., instinct) forces. Rats also present unique personality traits (repeatable behavioural differences among individuals across time and contexts) which likely contribute to their success as scent-detection animals. Considering a rat's personality traits and related cognitive styles when determining their scent-detection task assignment may improve training efficiency. We conducted open-field tests to characterise 25 rats' anxiety, exploratory, and locomotory behaviours. Exploratory and anxiety behaviours were repeatable across the year (exploratory: R = 0.38; anxiety: R = 0.30), indicating consistent personality traits. We also discovered female rats exhibited more exploratory behaviour than male rats. These results provide initial evidence for unique personalities in giant African pouched rats and support future investigations exploring if matching personalities to the specific demands of the scent detection task could bolster training.