Sexing Rodents and Rabbits Sexing Mice Anogenital distance
Sexing Rodents and Rabbits
Sexing Mice • Ano-genital distance (Longer in males) • Nipples Only in female mice • Notes: – Mice have an open inguinal canal – Testicles can be retracted into the abdomen – The scrotum is often not obvious (not a reliable indicator of gender)
Sexing Mice* *The Biology and Medicine of Rabbits and Rodents, 4 th ed. Harkness & Wagner, 1995.
Adult Mice
Sexing Adult Mice Ano-Genital Distance (Female) Ano-Genital Distance (Male) Nipples (Female)
Weaning Age Mice
Sexing Mice (Weaning Age) Nipples Ano-Genital Distance (Female) Ano-Genital Distance (Male)
Rat* Mouse* *Rats and Mice are born naked and helpless (Altricial)
Sexing Rats • Ano-genital distance (Longer in the male) • Nipples – visible by 14 days • The scrotum is more obvious in the rat
Sexing Rats* *The Biology and Medicine of Rabbits and Rodents, 4 th ed. Harkness & Wagner, 1995.
Rat
Sexing Adult Rats Short Ano. Genital Distance (Female) Obvious Scrotum (Male)
Sexing Hamsters • Scrotum is prominent • When the tail end is viewed from the top : – Male is rounded due to scrotal sacs – Female is pointed • Flank glands (more prominent in males) • Ano-genital distance
Sexing Hamsters* *The Biology and Medicine of Rabbits and Rodents, 4 th ed. Harkness & Wagner, 1995.
Hamsters
Sexing Hamsters Short Anogenital Distance (Female) Obvious Scrotum (Male)
Hamster Flank Scent Glands (More obvious in the male)
Hamsters Flank Scent Glands (Male) Posterior rounded scrotal sacs (Male) Pointed posterior (Female)
Sexing Gerbils • • Obvious scrotum Ano-genital distance is greater in the male Scent gland of the male is larger Female has nipples male does not
Sexing Gerbils* *The Biology and Medicine of Rabbits and Rodents, 4 th ed. Harkness & Wagner, 1995.
Gerbils
Ventral Abdominal Scent Gland (Larger in male) Ano-Genital Distance (Longer in Male)
Sexing Guinea Pigs • Scrotal pouches • Penis can be extruded from prepuce • Female has a U shaped vaginal opening – May be closed by vaginal closure membrane • Both Male and Female have nipples • Ano-genital distance is not a good indicator of the gender of a guinea pig
Sexing Guinea Pigs (Male) *The Biology and Medicine of Rabbits and Rodents, 4 th ed. Harkness & Wagner, 1995.
Guinea Pig (Male) Prepuce Anus
Guinea Pig (Male) Digital pressure extrudes the penis from the prepuce
Guinea Pig (Female) *The Biology and Medicine of Rabbits and Rodents, 4 th ed. Harkness & Wagner, 1995.
Guinea Pig (Female) Urethral opening “U” Shaped vaginal opening Anus
Sexing Rabbits • Mature males – Penis is easily extruded – Hairless scrotal sacs • Ano-genital distance is not an indicator of gender
Rabbit (Male) Hairless Scrotal Sacs
Rabbit (Male) Penis is extruded by stretching the perineal skin
Female Rabbit Male Rabbit Anus Penis Vaginal opening Stretching the perineal skin of the female reveals a slit like vaginal opening Stretching the perineal skin of the male prolapsed the penis
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