Cx43OT mice exhibit increased cortical bone resilience to fracture that is maintained with advanced age. Cortical bone biomechanical properties structural (A) and material (B) were evaluated by femoral 3‐point bending testing. Six‐month‐old mice: n = 7 WT and n = 5 Cx43OT, 14‐month‐old mice: n = 11 WT and n = 8 Cx43OT. Bars represent mean ± SD, *p < 0.05, versus 6‐month‐old genotype‐matched mice by two‐way ANOVA, Tukey, black line: p < 0.05, versus old control mice by t test.