The FeCl3 cartoid artery injury model [24], a well-characterized arterial thrombosis model, was used to induce an occlusive thrombus in the B6 and A/J mouse strains under investigation. A marked difference in arterial thrombus occlusion time was found between the B6 and the A/J mice (Figure 1A). The occlusion time in the A/J mice was 2-fold less than for the B6 mice. A 5% dose of FeCl3 was tested in the A/J and B6 mice and the occlusion time was lower in the A/J than the B6 mice, the same results as with the 10% dose. The occlusion time (min for both B6 (15 ± 3, n = 3) and A/J (8 ± 1, n = 3) at 5% were longer than at 10% for B6 (10 ± 1, n = 17 and A/J (5 ± 2, n = 14). The curves of blood flow after FeCl3 application indicated a pattern with a gradual decrease before occlusion for the B6 mice (Figure 1B), but for the A/J mice the blood flow decreased abruptly to zero (Figure 1C), demonstrating a marked difference from the B6 strain. The mean occlusion times were significantly different between the two strains (Figure 1A). The size of the carotids in the two strains was noticeably different. The area (mm2) of the lumen (0.066 ± 0.007, n = 6) was significantly less in the A/J mice than for B6 mice (0.128 ± 0.007, n = 6). However, the ratio of the thrombus to lumen was similar for A/J (0.63 ± 0.03) compared to B6 mice (0.67 ± 0.09). Calculated sheer stress rates [25] were 14% less in the A/J mice when compared to B6 mice.