According to Wikipedia.com Toto went missing during a storm and was later found to have passed away.
You can find this under the Big Cat Diary entry under "The cats: Cheetahs".
Big Cat Diary - 1996 Little Toto was released on: USA: 12 June 2009
The cast of Big Cat Diary - 1996 includes: Toto The Cheetah Honey The Cheetah Bella The Leopard Tamu The Lion
Big Cat Diary - 1996 Where's Toto? was released on: USA:12 December 2007
The duration of Big Cat Diary is 1800.0 seconds.
Big Cat Diary ended on 2008-12-24.
Big Cat Diary was created on 1996-09-11.
Big Cat Diary - 1996 is rated/received certificates of: Australia:PG USA:TV-G
Big Cat Diary - 1996 The Ambush was released on: USA: 3 February 2001
Big Cat Diary - 1996 Update was released on: USA: 3 December 2005
well i hope big cat diary comes back on i love that show but now i neever see it and now my hart is broe i will miss you big cat diary i hope you come back from oliviaharvey
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Big Cat Diary - 1996 Cub's in Peril was released on: USA:31 July 2008