Behaviors related to positive, neutral, or negative valence in Odocoileus virginianus in below-ground-level or ground-level exhibitor and influx of visitors

Abstract

The frequency of behaviors related to positive, neutral, or negative emotional valence in Odocoileus virginianus in two zoos was compared, with below-ground-level (3 m) (BGe) or ground-level (Ge) exhibitor during days of no, low, and high influx of visitors. In BGe, 11 deer with visual barriers and 4 m from visitors were used and in Ge 18 deer without visual barriers and 2 m from visitors. The rest-relaxed, rest-alert, rest-on feet, and grooming were considered behaviors of positive valence. Trophic behaviors interaction, elimination, intake of feed, and intake of water as neutrals. The alarm-head posture, alarm-body posture, flight, and interruption as behaviors of negative valence. Scan sampling observations were performed in both zoos on alternate days, 6 days per week. During each week, a day of no, low, and high influx was used to determine the number of visitors and crowd noise (in decibels). The weekly observations were performed three times on each exhibitor 14 days apart. The medians of visitors’ affluence were compared using Mann–Whitney test and the means of crowd noise with analysis of variance (ANOVA) and post hoc Tukey HSD. A one-way multivariate ANOVA was used to identify which of the observed behaviors were sensitive to the exhibitor type or influx. Post hoc median comparisons served to establish differences between significant behaviors. In addition, Χ2 tests served to compare the cumulative frequencies of positive, neutral, and negative behaviors between exhibitors for the same influx. A different number of visitors was confirmed (P < 0.05) between low and high influx in both exhibitors but similar (P > 0.05) between exhibitors at the same influx. In BGe, the crowd was higher than in Ge only during no influx (P < 0.05), more visitors were not translated on significant higher crowd. On decrease order, the behavior displayed was positives > neutral > negatives that confirm the good general conditions in both exhibitors. Flight, intake of feed and water, and rest of feet resulted affected by the exhibitor type. During the absence of visitors, a lower frequency of intake of feed was observed in BGe and lower frequency of rest-relaxed in both exhibitors, probably due to a silent environment that demands on prey animals, higher levels of alertness, but also habituation could be involved. Positive behaviors were more frequent during low and high influx in both exhibitors suggesting habituation, probably stronger on Ge.