I have found that there is approximately a 92.8% chance for the gnu to retaliate when attacked. Here is how I drew this conclusion:
1. Spawn 1 gnu at a time and hit it once with the players bare hand.
2. Leave site and go to another spot (with no existing gnus) and repeat.
3. Keep careful record of the gnu's behavior. Did they attack or run?
4. Calculate chance to retaliate with this formula: # of time gnu attacked / 1000 total
- 928 Gnus attacked
- 71 Gnus ran
- 1 Gnu didn't respond in any way
71 running gnus / 1000 total gnus = 7.1% chance to run when provoked
1 unresponsive gnu / 1000 total gnus = .1% chance not to respond
There is quite a high chance for the gnu to retaliate, but they do not all of the time. Personally, I was quite surprised to find that there was a chance (a small one) that the gnu would remain unresponsive!!
I'm glad to have cleared up the argument on the SC Wiki, and I hope this helped anyone else caught up in an argument as well!!