What does Topdeck mean by Gorilla & Chimp Excursion permit?

For many of Topdeck passengers, the opportunity to trek through the Ugandan jungle to witness rare mountain gorillas in the wild is a rewarding and memorable experience.

This excursion is entirely optional, but due to admirable conservation efforts being made to ensure the gorillas' survival, only a limited number of gorilla permits are available per day. These permits must be pre-booked and paid in advance, and the cost is listed on each itinerary page featuring the Gorilla Trek. Please be aware that no company can reserve permits in bulk and they are assigned on a first-come, first-served basis, meaning that the sooner you book, the more likely it is that you'll be able to do this incredible trek.

Included in the permit cost is an excursion to track chimpanzees in their natural habitat at Kyambura Gorge, another unforgettable African wildlife encounter.