後足長，耳長からの日本産イエネズミ3種の同定方法の再検討

抄録

To confirm the usefulness of ear/hindfoot ratio (ear length/hindfoot length) in the identification of three house rats/mice, we measured ear/hindfoot ratio and tail ratio (tail length/head body length) for 45 black rats and 42 brown rats every seven days from 23 to 149 days of age. Ear/hindfoot ratio of 399 black rats, 142 brown rats, and 113 house mice carcasses were also measured. Ear/hindfoot ratios did not change significantly with growth in black rats and brown rats, and there was no overlap between species, but tail rates changed significantly and there was overlap between species. The maximum hindfoot length of house mice was 17.0 mm, and the minimum hindfoot length of black rats and brown rats was 19.5 mm and 25.0 mm. Ear/hindfoot ratio of the carcasses showed that the minimum value of black rats was 0.58 and the maximum value of brown rats was 0.55. These results indicate that, regardless of developmental stage, it should be possible to discriminate house mice from black rats and brown rats by hindfoot length and discriminate between black rats and brown rats by ear/hindfoot ratio.