Visitors and observers otter-ly influence the behavior and enclosure use of zoo-housed giant otters.

The potential impact of human presence on captive animal behavior has recently been the focus of considerable research interest, especially following 2020 and 2021 periods of enforced closure as a result of COVID-19 opening restrictions. It is important to investigate whether human presence represents an enriching or stressful stimulus to a range of zoo-housed species. In 2020, during an easing of lockdown restrictions, investigations of the "visitor effect" and "observer effect" were carried out, using the giant otter (Pteronura brasiliensis) as a model species. To investigate the impact of both visitor and observer presence, otter behavior and space use was recorded for a pair of on-show and a pair of off-show otters. Observations were conducted using either a human observer, or cameras, allowing the researchers to investigate otter behavior when no one was present at the exhibits. The Electivity Index was used to assess the otters' use of four enclosure zones. Overall, otter behavior was significantly impacted by observer presence, though the impact of an observer differed between individual otters. Visitors had a minimal effect on otter enclosure use, whereas observers had a greater impact, whereby otters used their pools less frequently and houses more frequently when observers were present. However, this change in zone use differed between individuals, with more dominant otters tending to make use of indoor zones more often when observers were present. Zoos should consider the potential impact of human presence on their animals and use both behavior and space use when conducting their investigations.