One of the main challenges with photographing the non-human animals at the zoo is shooting through glass. Sometimes you just can’t get an angle without any glare, but sometimes it doesn’t matter.
What is culture? One simple definition might be: a distinctive behavior shared by two or more individuals, which persists over time, and that ignorant individuals acquire through socially-aided learning.
Chimpanzees have a lot to gain from climbing the social ladder. It now appears that lower-ranking male chimps strengthen bonds with their friends in high places by alerting them to some good eats.