Mystery pond berries 2020-05-03

What are these mystery berries that grow on the beaver dam and on islands in the pond?

[Closeup]
Closeup

We think they’re probably some species of Smilax.

[Smilax berries]
Smilax berries

They apparently like to grow in secluded spots.

[In situ]
In situ

Here are more of them on a small island in the beaver pond.

[Context]
Context

[Closeup]
Closeup

[More berries]
More berries

-jsq