Me and my husband were clipping snoopys claws last night. His front ones looked good, but when we got to the back ones the two claws in the middle looked funny. Where the nail bed is it looks like its a dark color. It reminds me of when someone hits their nail with a hammer really hard and it turns colors. What causes this in cats?? Is it something that should be looked at by the vet asap? Both my kitties are strictly inside kitties....