When they were at Marwell they were never content in their single pair situation, though they did improve a little (mentally) when they bred obviously.
The recent pair at Marwell were very quiet in comparison to the original ones (1.2) which they had. That male was extremely pugnacious, constantly calling and racing around the hardstand, or goring the fence even.
As you said they stimulate each other in a herd situation, I think they gallop and gamble and do crazy antics when in the wild in larger numbers. Other wildebeest likewise.
