Reducing stress and stereotypic behaviors in captive female pygmy slow lorises (Nycticebus pygmeaus)

Abstract

Improving captive conditions of pygmy slow lorises (Nekaris and Nijman have recently suggested that the pygmy slow loris should be called the pygmy loris and is distinctive enough to warrant a new genus, Xanthonycticebu) (Nycticebus pygmeaus) poses many challenges because detailed aspects of their lives in the wild are incomplete. This hinders efforts to replicate sustainable environments for them. To improve their well‐being in captivity, eight rescued female pygmy slow lorises at the Japan Monkey Center (JMC) were socially housed in two types of groups following their solitary housing: two pairs and one group of four individuals. They spent much of their time in affiliative behaviors, as well as sharing sleeping sites after placement in a social group. The purpose of my study was to examine whether social housing helped in reducing stress by comparing fecal glucocorticoids and stereotypic behaviors when housed alone and when with conspecifics. Overall, the levels of fecal glucocorticoids were significantly lower when socially housed than when kept alone. One individual exhibited stereotypic behavior when housed alone, but this behavior disappeared after social housing. These findings support recent evidence that pygmy slow lorises are social animals and will benefit from group housing in captivity. We conclude that social housing of pygmy slow lorises improves their well‐being by reducing stress levels, and that their group housing in captivity can provide dividends for the conservation of this endangered nocturnal primate because lorises intended for release should find it easier to adapt to natural conditions.

Reproductive Behavior and Hormone Metabolite Profiles in Captive Breeding Female Sumatran Slow Lorises (Nycticebus hilleri)

“…K2 was observed to commonly rest in front of the cage, whereas K5 commonly rested on left front side of the cage near the cage door. In contrast to the pygmy slow loris (Nycticebus pygmaeus) at the Slow Loris Conservation Center at the Japan Monkey Center, the behavior of resting with other females in a wooden nest box (Yamanashi et al, 2021;Alejandro et al, 2023). Autogrooming behavior, which included scratching, licking, or pulling the subject's own hair, accounted for 5% of the observed behavior.…”

“…The pairing of the animals aims to maintain their social behavior as it is in the wild, especially reproductive behavior. Generally, unpaired animals tend to show negative behavior, and even stereotyped behavior (Gursky, 2002;Moore et al, 2015;Alejandro et al, 2023). Paired male and female animals, in general, do not face many obstacles.…”

“…However, not all pairs will exhibit reproductive behavior. This can occur if the pairing is not suitable (Alejandro et al, 2023;Jolles et al, 2020) and may depend on the influencing conditions and levels of reproductive hormones (Alejandro et al, 2023).…”