How do you find out if your dog as a tumor?

* Lumps (could be cysts and must be checked by a vet) * Lethargy * Not eating well * Not drinking water * Walking slow, often with tail between legs * Wanting to be alone and not with their owner or family * Not joining in with family fun as usual or any unusual difference in your dog. * Dark tarry stools. These are but a few signs and all of them don't pertain to cancer so it's important to see your pet as soon as possible for an evaluation.