Testis of Different Species: Size, Shape, and Position Across Animal Species

Testis of different species vary in shape, length, diameter, weight, and anatomical plane, reflecting species-specific reproductive physiology.

These variations influence not only reproductive function but also clinical approaches in diagnostics, fertility assessment, and surgical procedures across species.

Bull

The bull has vertically oriented, oval-shaped testes located in the anterior prepubic region. Their anatomical features are well-defined and consistent across breeds.

• Shape: Oval
• Length: 10–15 cm
• Diameter: 5–8 cm
• Weight: 200–500 gm
• Long Axis: Vertical
• Head of Epididymis: Lies dorsal to the testis
• Body of Epididymis: Lies caudal and medial to the testis
• Tail of Epididymis: Lies ventral to the testis
• Vas Deferens: Lies parallel to the body of the epididymis and is medial and cranial to it
• Location: Anterior prepubic region

Stallion

The stallion has horizontally oriented, oval testes that are slightly compressed laterally. They are positioned between the prepubic and perineal regions.

• Shape: Oval, compressed laterally
• Length: 7.5–12.5 cm
• Thickness: About 5 cm
• Weight: 200–300 gm
• Long Axis: Horizontal
• Head of Epididymis: Lies cranial to the testis
• Body of Epididymis: Lies dorsal to the testis
• Tail of Epididymis: Lies caudal to the testis
• Vas Deferens: Lies dorsal and medial to the body of the epididymis and testis
• Location: Intermediate to the prepubic and perineal region
• Appendix Testis: Present on the cranial pole; also seen occasionally in rams

Ram and Buck

In rams and bucks, the testes are vertically placed, oval in shape, and situated in the anterior prepubic region. They share similar dimensions and anatomical orientation.

• Shape: Oval
• Length: 7.5–11.5 cm
• Diameter: 3.8–6.8 cm
• Weight: 200–400 gm
• Long Axis: Vertical
• Head of Epididymis: Lies dorsal to the testis
• Body of Epididymis: Lies medial to the testis
• Tail of Epididymis: Lies caudal to the testis
• Location: Anterior prepubic region

Boar

The boar has large, vertically oriented testes located in the perineal region, with a long spermatic cord and distinct epididymal positioning.

• Shape: Oval
• Length: 10–15 cm
• Diameter: 5–9 cm
• Weight: 500–800 gm
• Long Axis: Vertical
• Head of Epididymis: Lies ventral to the testis
• Body of Epididymis: Lies cranial to the testis
• Tail of Epididymis: Lies dorsal to the testis
• Vas Deferens: Lies medial and cranial to the testis
• Spermatic Cord: Long
• Location: Caudal to thighs, caudal and ventral to the ischiatic arch (perineal region)

Dog

The dog has small, horizontally and obliquely placed testes, located intermediate to the prepubic and perineal regions. The epididymis follows a classic cranial-dorsal-caudal orientation.

• Shape: Oval
• Length: 2–4 cm
• Diameter: 1.2–2.5 cm
• Weight: 7–15 gm
• Long Axis: Horizontal and oblique
• Head of Epididymis: Lies cranial to the testis
• Body of Epididymis: Lies dorsal to the testis
• Tail of Epididymis: Lies caudal to the testis
• Vas Deferens: Lies dorsal and medial to the body of the epididymis
• Location: Intermediate to the prepubic and perineal region

Tom Cat

The tom cat possesses small, oval testes that are located in the perineal region. Though compact, they are anatomically distinct in terms of size and placement.

• Shape: Oval
• Length: 1.2–2 cm
• Diameter: 0.7–1.5 cm
• Location: Caudal to thighs, caudal and ventral to the ischiatic arch (perineal region)