Giraffe diurnal recumbent behavior and habitat utilization in Katavi National Park, Tanzania

Resting behaviors play an important role in animals' daily activities by minimizing energy consumption. Although this may be equally important to other behavioral states for sustaining life, it has not been well studied in the giraffe (Giraffa camelopardalis). This study characterized the bout duration, frequency, and age-sex class differences in diurnal recumbent behavior of free-ranging giraffe. Additionally, it is currently unknown whether giraffe utilize shady or safe areas for diurnal recumbency, as many other animals do. Therefore, we also investigated this in the present study. Data were collected in Katavi National Park, Tanzania, during four time periods. The duration of recumbency bouts was calculated from 170 episodes, and the frequency of recumbency was determined by following 24 individuals for more than 10 h each. Habitat type was categorized into wooded grassland or miombo woodland, and habitat preference was analyzed based on 173.6 h of observations. We found no significant difference in the duration of recumbency bouts among the four age-classes and between sexes in adults. On the other hand, calves (n = 2) rested more frequently than did other age-groups, possibly due to differences in predation risk or activity budgets. Adult males had a higher frequency of recumbency compared to adult females, possibly because pregnant/nursing females were hindered in adopting this posture. We also found that giraffe primarily utilized the miombo woodland for daytime recumbency, likely because the high tree density reduces heat stress, and its seclusion from the river reduces predation risk.