When I was a student at San Diego State I took an experimental psychology course in primate behavior. The proffessor was Dr. Chris Parker. WE spent a lot of our time at the San Diego Zoo observing the primates there.

Chris had done a lot of work with the gorillas and the orangutans there and related a story to us about one of his experiments.

He was in the crowd one day observing Albert,the patriarch Silverback who used to be at the zoo. Someone in the crowd made the comment that a gorilla was as strong as ten men. Chris began to wonder "How do you prove that statement"? Do you put a gorilla at one end of a rope and ten men at the other?

What he came up with was a tube filed with garage door springs witha handle at one end and a tension gauge at the other.This extended through a concrete wall into the gorilla enclosure.Albert would get a reward of a banana slice upon reaching a predetermined tension. The interesting part came when Albert started placing his banana slices on the window where Chris was observing. When Albert failed to pull the handle sufficiently to get a reward he would reach up and take one of his stockpiled slices and reward himself anyway.

As to the strength of the pull? Well over 800 lbs and when Albert reached the point of reward he would simply let go of the handle allowing every thing to crash back into place. Chris said the entire building shook when he did that.

Another interesting note was that Chris also tried the experiment wth Bob, the old orangutan. Bob not only pulled more than Albert(over 1000lbs) he did it one handed and with complete control would slowly let the springs return with nary a sound.

rr