Turning on the dirt road to the Gibbon Conservation Center (www.gibboncenter.org) in Santa Clarita, California, I had a random thought and asked my co-worker, Todd, who was driving, if monkeys (at that time I did not know that Gibbons are actually apes) screamed. “I don’t think so, I think they are quiet creatures,” Said Todd. Todd was wrong.

Maybe screaming isn’t the right...