In the animals natural enclosure I would presume and not under the glare of studio lights.
From the guardian.co.uk
Their enclosure is a natural setting, with a waterfall, rock formations and fallen trees for climbing.
From the newsobserver.com
Their enclosure is designed to resemble a dry river bed, the Dragon's natural habitat, and sounds of Indonesian birds are regularly played into the enclosure.
From the en.wikipedia.org
Also, the sample must be at room temperature to prevent natural convection from forming air currents inside the enclosure, affecting the measure of mass.
From the en.wikipedia.org
However, the generally messy nature of swamps, with their diffuse boundaries and lack of enclosure, prevents humans from being able to collect and capitalize on their natural resources.
From the en.wikipedia.org
Enclosure tours last 90 minutes to two hours and visit six areas where lemurs can be seen roaming freely in something approximating their natural environments.