Figure 1:

Apparatus and tethering setup for partner preference test. A: Linear apparatus and tether setup. One familiar and one novel individual are tethered in the end chambers. In the standard PPT, the focal animal is of one sex and the partner and stranger are of the opposite sex. In the peer partner preference test (pPPT), all animals are of the same sex. B: Close-up of tethered meadow vole showing attachment of the swivels to the crimped wire loop of an anchor. Metal components are used for the reusable portion of the tether; plastic zip-ties are cut at the end of each test. C. Close-up on a prairie vole, tethered to a fixed anchor. D. Slide-in and clip-on tether attachment systems. E. Schematic of a branched PPT setup. Branched apparatuses may be constructed of cages covered with clear, perforated lids, or as tall-sided custom chambers.