Order and species

Spiral turns

Basilar membrane length (mm)

Lower and upper hearing range (kHz)

Rodentia

Guinea pig Cavia porcellus

4.25

18

19

0.045

49

Chinchilla Chinchilla langer

3

18.5

0.05

33

Laboratory rat Rattus norvegicus

2.25

9.7

0.39

72

Laboratory mouse Mus musculus

2

7

0.9

79

Mongolian Gerbil M. unguiculatus

2.75

11.67

0.1

60.0
Table 1: The spiral turns of the cochlea and basilar membrane length with the range of audible frequencies from a selection of rodents (adapted from Lovell and Harper [46]) and includes data for M. unguiculatus.