 When Mrs. and Mr. Test aren't around, Dukey will stand on his hind legs rather than all fours.The reason for this is that Hugh banned Susan and Mary from DNA experiments, which was how they gave Dukey human-like intelligence.There have been a few "close calls" around the series, such as when Mr. Test got trapped inside of one of Johnny's video games and Johnny and Dukey also went inside the game to rescue him, and Dukey accidentally spoke in front of him, causing Hugh ask, "Did Dukey just talk?"