Historical clue formulations

• So-called "African unicorns" — 2020-01-18
• Cousins of giraffes — 2014-10-13
• Rain forest denizens — 2007-04-27
• Striped animals — 2006-04-01
• Striped African animals — 2005-08-21
• Congo forest dwellers — 2001-11-29
• Nocturnal animals of the upper Congo — 2000-08-06
• Giraffes' cousins — 1998-08-16
• Giraffe-like ruminants — 1997-09-03