Why are my dogs testicals swollen?

I have an 8 year old miniature schnauzer who is not neutered. He isn't on any medications and he is an indoor dog, only goes outside to play or do his business.

I'm sitting on the couch with him right now and I just noticed that his testicles are huge and shiny looking.. Weird I know.. He doesn't appear to have any bites and he doesn't seem to be in any pain, he's moving around normally. I have another much larger labradoodle that just turned 1, so he's very hyper and rough with him. What could cause this and what should I do?

?2016-10-01T17:16:09Z

Swollen Testicals

?2013-07-24T22:19:36Z

My mini mix schnauzer/dachshund about 6 years old, male has a hard swollen testes. He acted unwell, no appetite yesterday. Another large female dog had been in heat. Not sure what is wrong with the male dog.

I am a Soldier2013-07-24T21:05:25Z

He needs to release.

Anonymous2013-07-24T21:03:05Z

Why are you looking at your dogs testicles?

Anonymous2013-07-24T21:02:46Z

testicular cancer?