Historical clue formulations

• ___ brain (source of our primal instincts, it's said) — 2024-10-29
• Monitor, e.g. — 2021-02-13
• Source of some leather — 2016-06-10
• Skink, e.g. — 2014-11-20
• Komodo dragon, for one — 2013-07-10
• Some shoe material — 2006-10-06