“…Although the intromission ratio calculated for Straiko's subjects was 15% lower than that presented in the current report (35% vs. 50%, respectively), this may result from differences in the duration of exposure to receptive females. Straiko et al (2007) were interested in the subjects copulating to a single ejaculation to use for place conditioning, and thus there was no recording of a PEI, precluding a comparison. Aside from specific reports using the SD strain, male sexual behavior has been well characterized in other outbred rodent strains (e.g., for Wistar rats see Agmo & Berenfeld, 1990;Agmo & Gomez, 1993;Camacho et al, 2004;Martinez & Paredes, 2001;Paredes & Alonso, 1997; for Long-Evans rats see Damsma, Pfaus, Wenkstern, Phillips, & Fibiger, 1992;Pfaus et al, 1990;Robertson, Pfaus, Atkinson, Matsumura, Phillips, & Fibiger, 1991;Westerman, Roma, Creed, Hurwitz, & Dominguez, 2009).…”