In recent years the importance of observing zoo animals throughout 24 hour periods to fully capture their behaviour and thus welfare state has been advocated. Yet there are difficulties associated with observing animal behaviour over-night, when typically keepers are not present. Camera systems may be absent from zoological facilities or may be of poor quality in lower light levels and this makes observations difficult to undertake. It is possible that animal behaviour differs when keepers are absent and being able to identify important behavioural indicators of welfare (e.g. sleep patterns) overnight are important. For many zoo species there is a paucity of information as to overnight behaviour, despite the recognised need for this information. As there are large periods of time when animals are left alone overnight it is paramount that means of assessing overnight animal behaviour are identified, especially in intelligent species who may be highly influenced by observer presence.
The presence of an observer, especially during zoo closure hours has the potential to impact on behavioural observations. Tracksys Ltd provided a Hikvision video camera with infra-red recording capabilities which was installed in the spider monkey enclosure at Bristol Zoo Gardens to capture overnight behaviour of the group. This video camera enabled Violet Hunton, a masters student from University of Bristol to conduct some preliminary work to understand more about behaviour of the spider monkeys, a critically endangered primate species, when keepers and visitors are not present.
Increasing our understanding of animal behaviour overnight is advocated and is being increasingly incorporated into best practice recommendations for animal care. The use of video cameras with infra-red recording capabilities is important in order to non-invasively monitor animals throughout 24-hour periods. This research can contribute towards the validation of a sampling method which enables routine assessment of overnight behaviour to be incorporated into behavioural assessments of zoo animals moving forwards.