|
Male rat
|
Female rat
|
|
1.
Larger in size
|
Smaller in size
|
|
2.
Nipples are degenerate
|
6 pairs, fully functional, 3 pairs in thorax and 3 pairs
in abdomen
|
|
3.
Scrotal sacs present
|
Absent
|
|
4.
Penis present
|
Absent
|
|
5.
Vulva absent
|
Present
|
|
6.
Urethral opening at the tip of the
penis is common opening for the passage of the sperms and urine
|
Separate opening in front of vulva
|