It is related that Rubens caused a remarkably fine and powerful lion to
be brought to his house, in order to study him in every variety of
attitude. One day, Rubens observing the lion yawn, was so pleased with
his action, that he wished to paint it, and he desired the keeper to
tickle the animal under the chin, to make him repeatedly open his jaws;
at length, the lion became savage at this treatment, and cast such
furious glances at his keeper, that Rubens attended to his warning, and
had the animal removed. The keeper is said to have been torn to pieces
by the lion shortly afterwards; apparently, he had never forgotten the
affront.