create a loop that adds values

is it poissible vba code to loop down column A for and for each value "cat" add up the associated value for it in column B on the same row and show the answer in column C?
i.e
A B C
cat 1 answer 9
dog 2
cat 5
dog 1
cat 3

hope someone can help thanks

lol thats exactly what i wanted thanks, think i was tyring to overcomplicate it.
many thank yous