Conversation so far:
What period of history was th Jumbo article about?
1860
Do you know where Jumbo the elephant first came from?
East Africa
What was significant about Jumbo compared to other circus elephants?
Jumbo became a crowd favorite due to his size

Question: Why was he grinding his tusks? Was he going crazy or sick?
Self-contained rewrite: Why was Jumbo grinding his tusks? Was he going crazy or sick?