Feeding interactions in Pygoscelid penguins normally involve chases where a parent runs and is closely followed by its chicks. Several hypotheses have been advanced to explain this behaviour. Studies with chinstrap and Adélie penguins indicate that feeding chases are mostly associated with a one-parent/two-chick situation. Chases are almost absent in one-chick broods, or situations in which one sibling is removed from the crèche and only the remaining sibling begs for food. Data are consistent with the hypothesis that chases serve to separate siblings in two-chick broods in order to feed them more efficiently.