Ben Fogle and Kate Humble are back for another sun-filled summer series, following the extraordinary lives of the exotic animals at Longleat Safari Park and the keepers who look after their every need. Today, we find out how the keepers' continued vigilance and dedication to the animals' welfare can alert them when something seems to be wrong.There's another milestone for Hazel, the first southern koala born in Europe. She has to be separated from her mother for a short period. This is to ensure that the keepers earn the baby's trust before she becomes impossible to work with. Without this, the park wouldn't be able to perform their routine and important health checks. But can the keepers separate Hazel from her mum for ten minutes without distressing either of them?Also, one of the keepers has noticed that the park's monitor lizard has a worrying issue with his spine. A specialist osteopath, who takes care of zoo animals that suffer from muscle or joint problems, is brought in to investigate. If he can't treat the lizard, the keepers will have to resort to giving him medication, a dangerous job for those who look after him. The osteopath decides to use laser therapy on the lizard, but will it work?Elsewhere in the park, it's not just the animal keepers who are kept on their toes. The housekeepers of Longleat have their hands full hunting for carpet beetles that munch away on natural fibres like wool and silk. Kate heads inside to help in one of the house's 135 rooms. Ben celebrates a white-fronted brown lemur's 28th birthday, but what type of cake does a lemur enjoy?Megan McCubbin finds out how the keepers train the nervous bongos to accept medical procedures like medicine and blood tests. Hamza Yassin has been given a task by the head of animal operations: to record the number of different wild birds he can spot in the park in just an hour. It's a useful barometer of the diversity of native species in the park.