1979 - 1997
Note: This comes from The Lego Book.
The DUPLO rabbit was first used on packaging in 1979. In 1997, it was redesigned with a friendlier appereance to match the new PRIMO elephant logo for infant toys.
1997 - 2002
Note: This also comes from The Lego Book.
It disappeared in 2002, when DUPLO was merged into the new LEGO Explore theme for young children, but returned when the DUPLO name appeared once again in 2004.