*5.6. Evaluation of Maternal Behavior*

Each female was provided with shredded paper one day before delivery for nest making. Maternal care was recorded with a digital camera (Canon Vixia HF R800, Tokyo, Japan) for 2 h after venom or 0.9% NaCl injection on PN2, PN10, and PN16. The time of arched-back nursing posture was recorded. Statistical analyses were performed by two-way ANOVA, and the level of significance was set at *p* < 0.001.
