Mammillary Bodies: Size Comparison in Humans vs. Sheep

The mammillary bodies are paired, oval nuclei on the ventral hypothalamus, part of the limbic system critical for memory (especially episodic) and emotional processing.

Human Mammillary Bodies

• Dimensions: ~10–12 mm length × 6–8 mm width
• Location: Base of the brain, inferior to the hypothalamus, adjacent to the pituitary stalk

Sheep Mammillary Bodies

• Dimensions: ~15–18 mm length × 10–12 mm width
• Location: Anatomically similar—ventral hypothalamus at the brain base

Comparative Note

Sheep mammillary bodies are ~50% larger in linear dimensions, consistent with overall brain size scaling. Both species rely on these structures for hippocampal-hypothalamic connectivity via the fornix, supporting spatial memory and neuroendocrine integration.