Help Identify these

I am finding these under what appears to be BlackJack Oaks, not sure if they are some kind of fruit or egg for some bug. They look to have a hole in the middle and something is opening them up, maybe squirrels.
It's a new home to us, so I haven't seen them before.

Oak galls.

What does that mean

It's just a defect in leaves and twigs. Typically harmless.

https://entomology.ca.uky.edu/ef408

Gall wasp larva cause this.

Learned something new. Thanks

Not always. Some are caused by gall wasps but others naturally occur and the gall wasp will impregnated the gall with a larva.

Thanks for the info. I saw a whole bunch of those also under very old oak at lease last weekend

I've never seen one that didn't have the larva inside or a hole where it ate it's way out, so I'm thinking virtually all are from gall wasps. I'm sure there are exceptions to everything in nature though.

They may all have a larva inside but not all galls are made by the wasp itself.

Well...mystery solved, Thanks gentlemen.

Yup..wasp galls.....