Wikipedia
A bear-leader was formerly a man who led bears about the country. In the Middle Ages and Tudor times these animals were chiefly used in the brutal sport of bear-baiting and were led from village to village. Performing bears were also common; their keepers were generally Frenchmen or Italians.
Later, the phrase "bear-leader" came colloquially to mean a tutor or guardian, who escorted any young man of rank or wealth on his travels.
In the 18th and 19th centuries, a bear-leader was a colloquialism for a man who escorted young men of rank or wealth on their travels, such as young gentlemen on the Grand Tour. The role of bear-leader blended elements of tutor, guardian, chaperon and companion. A late example in literature can be seen in the ambitious Oxford tutor hired to keep an increasingly alcoholic young man out of harm's way – and out of the way – in Brideshead Revisited.