It's hard for me to tell from the pic, old eyes and all that.
It could very well be cecal (ceacal) poop, but it could also be a sign of worms. I'm fairly certain its cecal, but I would click on the link in post #2 to compare and be sure.
Hi and welcome to BYC!
Does the diarrhea look like melted chocolate?
Without signs of illness it could be cecal poo that you are noticing; which is completely normal and happens every 6 to 10 movements.
Here's a handy guide (w/graphic pics!) to help you decide if it is cecal poo you are...