Table 1.

Resident-intruder test in MSM and B6 males.

	B6		MSM
	1st	2nd	1st	2nd
NUMBER OF ANIMALS
Total resident males	19	19	16	16
Males that showed attack bites	2	4	14+	15+
% aggressive males	10.5 %	21.1 %	87.5 %	93.8 %
DETAILED BEHAVIORS
Attack bites (f)	3.4 ± 2.3	5.7 ± 2.7	42.9 ± 6.0**	33.8 ± 6.1**
Sideways threats (d)	2.9 ± 2.0	5.7 ± 4.0	6.2 ± 1.7	4.0 ± 0.9
Tail rattles (d)	1.2 ± 0.8	2.5 ± 1.4	8.8 ± 1.4*	8.1 ± 3.5
Pursuit (d)	0.8 ± 0.7	0.7 ± 0.5	70.3 ± 10.2**	50.1 ± 8.9**
Walking (d)	124.8 ± 8.8	102.5 ± 7.4	57.4 ± 5.8**	62.1 ± 8.0**
Rearing (d)	43.1 ± 3.9	34.6 ± 4.6	18.5 ± 3.9**	18.7 ± 4.1*
Grooming (d)	7.8 ± 1.8	8.6 ± 2.0	6.3 ± 3.7	9.3 ± 4.9
Contact (d)	44.7 ± 5.5	39.6 ± 6.3	21.7 ± 12.7	11.9 ± 10.1*
Attack latency	287.9 ± 9	263.5 ± 18	172.7 ± 23**	99.2 ± 24**

Significant strain differences between B6 and MSM are indicated as

⁺p < 0.05 by Fisher's exact test, and

^*p < 0.05 and

^**p < 0.01 by the Tukey-Kramer test. (f): frequency, (d): duration.