As of 2015, there are 10 mountain gorilla groups habituated making it 80 gorilla permits for visitors to Rwanda available every single day. 8 people per group can trek to these endangered apes. With a gorilla permit costing US $ 750 per person per trek, part of your contribution goes to conserving these mountain gorillas. Armed guards follow the groups 24 hours a day! The decision of which group you may visit is made on the morning of your trek by the wardens. Consideration is given to fitness levels and desires of length of trek may be considered.