Effects of honey locust seed pods on the behavior and nutrient intake of zoo-housed François langurs and prehensile-tailed porcupines.

Seed pods represent an under-utilized and valuable dietary resource for zoos because they encourage naturalistic extractive foraging behavior and because seeds pods, like leafy browses, are more fiber-rich than most dietary items typically offered in zoos. The primary goal of this study was to examine the effects of honey locust (Gleditsia triacanthos) seed pods on the behavior and macronutrient intake of zoo-housed François' langurs (Trachypithecus francoisi; n = 3) and prehensile-tailed porcupines (Coendou prehensilis; n = 2) using a pre- versus postdiet implementation design. From December 2019 to April 2020, we recorded behavior using instantaneous interval sampling and daily macronutrient intake via dietary intake records. We found that time spent feeding increased (p < .001) and stereotypic behaviors decreased (p < .001) for the François' langur group during the seed pod phase. The prehensile-tailed porcupines also exhibited increased time spent feeding and decreased inactivity (p < .001 for all comparisons) during the experimental seed pod phase. We found no differences in macronutrient intake for the François' langur group. The female prehensile-tailed porcupine consumed more neutral detergent fiber (NDF) in the seed pod phase (p = .003) and the male consumed more crude protein, NDF, nonstructural carbohydrates, and crude fat (p < .001 for all comparisons). We stress that honey locust seed pods are a fiber-rich (i.e., ~40%-55% NDF by dry weight) dietary option for zoo-housed folivores and promote positive welfare by encouraging naturalistic foraging behavior and may help increase foraging time and decrease stereotypic behaviors.