What did Mambo the aquarium sunfish regain his appetite for when pictures of human expressions were posted?

Mambo the aquarium sunfish regained his appetite for "faces" when pictures of human expressions were displayed. This phenomenon emphasizes the significance of visual stimuli in animal behavior, particularly how certain images can trigger responses in animals. In Mambo's case, the presence of human faces likely piqued his curiosity and social interest, which is essential for engaging the sunfish and encouraging him to eat.

Research has shown that many animals respond to social cues and visual stimuli in their environments, which can influence their behavior including feeding habits. The images of human faces could have created a more stimulating atmosphere for Mambo, motivating him to eat as a result of increased engagement with his surroundings.

The other options, while potentially relevant to a discussion about animal behavior, do not capture the specific relationship between Mambo's appetite and the images of human expressions seen in the aquarium.