Episode 5

Hidden away above the bat cave, conservationists are investigating a worrying decline in one of the park's rare native bat colonies. Numbers have fallen sharply, and there are fears another species may be threatening the next generation. As the team search for answers, they hope to discover whether the colony can recover before more bats are lost. As part of the show's silver anniversary celebrations, Ben and Kate revisit one of the most memorable stories from the past 25 years.

As the anniversary celebrations continue, Ben and Kate look back at the time a binturong mysteriously started refusing food, seriously worrying the keepers. The only option is an anaesthetic to try to get to the root of the problem, but with any procedure of this kind there is always a worry that the animal may never wake up.

Elsewhere, the keepers celebrate an important milestone as a critically endangered white-backed vulture chick reaches a crucial stage in its development. Megan McCubbin also joins the keepers to weigh the park's three male gorillas. With each weighing more than twice as much as the average adult man, it's no easy task getting them onto the scales.