### STUDIES ON THE AGE DETERMINATION INDICES OF YARKAND HARE(LEPUS YARKANDENSIS)

CHEN Yongguo, ZHOU Yongheng, NIE Wenkui

• Online:2006-07-29 Published:2008-07-07

### 塔里木兔年龄鉴定指标的研究

1. 新疆八一农学院，乌鲁木齐

Abstract: In order to determine the ages of Yarkand Hare(Lepus yarkandensis)，seveen growth indices of the specimens were studied by using prineipal component analysis，They were body weight，head and body lengths，full skull length，zygomatic width，the length of incisive foramen，mandibular length and the dry weight of eye lenses．On the first principal component axis (Z1)， the contribution rate of the male correlation matrix was 79．36 %while the female one was 88.97%． The analyzed indices arranged in order of factor load Oil the first principal component axis， showed the following findings：
1．On the axis of Z1 male and female full skull lengths had the greatest factor
Loads．So，full skull length could reflect the growth best．
2．The factor loads of the length of incisive foramen and mandibular length on Z1
were above 0．93． So both the lengths could be used as age indices．
3．Although body weight and head and body lengths were convenient age indices，it was not easy to measure the head and body lengths accurately and the exact body weight would be affected when female hare were pregnant．
4．Dry weight of eye lenses was not a suitable age index for Yarkand Hare because of their small factor loads on Z1.
To sum up，the full skull length would be used as the age indicator for Yarkand
Hare． Through further analysis， the population of Yarkand Hare could be divided into three age groups：juvenile (full skull length was less than 69．00 mm )， subaduh(69．OO一75．5O mm) and adult groups (over 75．50 mm)