The purpose of this study is to establish reference data on several he
matological parameters in the cotton rat. Eight hematological values w
ere measured in 28 males and 29 females at 16 to 18 weeks of age. Fema
les showed significantly lower RBC, Ht and MCV values than males. Fema
le Hb and PLT values tended to be lower than male values, although dif
ferences did not reach a conventional level of significance. WBC and P
LT values varied widely in both sexes.