Chicks' Begging Calls are Graded in Intensity

Question

Chicks' begging calls are graded in intensity. This is a signal that appears to be
A) dishonest, because each chick will always benefit by out-begging its sibling, whether it is really hungry or not.
B) dishonest, because there is little cost associated with begging too much.
C) honest, because research has shown that the vigor of begging increases with hunger.
D) honest, because the parents can always detect a manipulative message by a chick.

Accepted Answer

The vigor of begging in chicks has been shown to increase with hunger, indicating that the intensity of their begging calls is an honest signal of their need for food. This relationship suggests that the more a chick begs, the more likely it is that it is genuinely in need of nourishment, making the signal honest rather than manipulative or dishonest.