It may be that as the dog ages, he will develop dark spots caused by pigmentation, endocrine and other reasons. If the dark spots on your dog's testicles feel smooth and flat and cannot be rubbed off, they are normal pigmentation. If your dog’s black spots are scabbed and your dog has other adverse symptoms, you should go to the pet hospital to check the cause in time.

If there are dark spots on the dog's testicles, you can wipe them to see if they are dirty. If not, check to see if the dog's testicles are inflamed. There may also be black spots caused by mites, and special anthelmintics can be used to remove the mites.