Try this Formula instead
Substitute the NEW for the OLD in the supplied Spreadsheet.

OLD =LOOKUP(F3,A$3:A$7,B$3:B$7)

NEW =VLOOKUP(F3,A$3:B$7,2)

And again, your database of animals must be in alphabetical order.

EDIT : The above Formula goes into cell G3 in the spreadsheet.
Copy this cell all the way down to G7