Rats know where other rats are through activation of particular cells in the hippocampus
I know where you are! Social place cells in the hippocampus tell me!

Bats and rats use the same neural region, the hippocampus, to orient themselves in space, and to track the whereabouts of their conspecifics, two independent research groups found. The animals use the already known “place cells” that encode their own location, and newly-found “social place cells” to code for the position of the others. These cells may be especially important for social animals (like rats, bats and humans), as knowing where conspecifics are facilitates communication, learning, or moving together.

Read the full story: www.nature.com/articles/
Scientific publication: science.sciencemag.org/content/bats
Scientific publication: science.sciencemag.org/content/rats