Anthropologist and spider monkey expert Dr. Christina Campbell joins the gang this week to get an update on Jesse's kidney stones and talk about her field of expertise, including research on Barro Colorado Island, the snubbing of Darwin contemporary Alfred Russel Wallace, Jesse trying to adopt a wallaby, Chris Burke’s Eating Is Fun/Eating Is Serious, Dr. Campbell's book on spider monkeys, the torture tape experiment, wombats and wallabies, barrel of monkeys vs. barrel of apes, chimps catching bushbabies with spears, the relative intelligence of Koko vs. Kanzi, the 1980s orangutan movie Link, spider monkey trivia, why you shouldn't use sign language in front of primates, why you shouldn't tickle a slow loris, spider monkey sexual rendezvous and the drunken monkey hypothesis.