How to Sum based on criteria

Hi,
Look This example :
-------A---------------B
blastranger------100
rangerblade-----200
blastranger------200
Monkey----------300
Rabbit------------400
rangerblade-----500
Monkey----------100
Rabbit-------------200

I want to sum the Value of blastranger and Rabbit which will return result :
900

I use SUMIFS(B1:B8,A1:A8,"blastranger",A1:A8,"Rabbit")
the result is 0

I wonder why it is 0, how to sum using SUMIFS, or do I make some mistake here?