The rat tail contains a dorsal vein ... Collecting blood from rodents: a discussion by the Laboratory Animal Refinement and Enrichment Forum. Anim. Technol. Welf. 4(2), 99–102 (2005).
Furthermore, the animal is free to move about ... First, she submerges the rat's tail in a cup of warm water (50°C) for 3–5 min. Next, she rubs gently both lateral sides of the tail ...