91热爆

Infra-red lighting doesn't disturb the bats' natural behaviour and allowed covert filming with tiny IR sensitive cameras inserted inside the bamboo. The high definition cameras used for the series were only able to slow action down to half speed, so to slow the fast-flying bats down sufficiently to see them as they left the nest, good old-fashioned super-16 film was used and the resulting footage slowed down six times.