How to choose Marker based upon 'type' field

I have a field that is different from the 'content type' field. I dont want to add another field to hold the markername, so I was looking for an easy work around where the marker could be determined by the contents of another field.

For instance.

if $type = "snake" then $marker = "green"

if $type = "bear" then $marker = "brown"

etc.

Just trying to cut down on the number of fields in my DB that hold redundant information.