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Cetacean Anatomy · Interactive Diagram

Dolphin Mammary System
Concealed Slits & Aquatic Nursing

Blowhole (naris) Rostrum (beak) Mammary slit (click & drag to express) Paired slits (concealed nipples) Genital slit Ventral (belly) surface Cross-section detail Mammary slit (open) Skin (epidermis) Blubber layer Mammary gland tissue (one each side) Milk duct openings
Click & drag down on a mammary slit to express milk
Collected 0 mL

Concealed within slits

Dolphin nipples sit inside protective mammary slits, kept flush with the body for hydrodynamics. The slits open only during nursing bouts.

Muscular milk ejection

Unlike land mammals, dolphins actively squirt milk under muscular pressure directly into the calf's mouth — no sustained suckling required.

Paired mammary glands

Two mammary glands sit beneath the blubber layer, one behind each slit, on the ventral surface between the navel and genital slit.

Extended nursing

Despite each bout lasting just 5–10 seconds, dolphin calves nurse for up to three years — dozens of times per hour while swimming alongside their mother.

Milk Profile

15–20%
Fat
8–11%
Protein
~1%
Lactose
~1,400 kcal/L
Energy
Calf Daily Intake
~1.5 L
In 5–10 sec bursts, dozens of times/hr
~2,100 kcal per day
vs
Human Serving
240 mL
1 standard cup
~336 kcal per cup

Taste & Texture

Extremely thick and oily, resembling heavy cream infused with fish oil. Ivory to pale yellow in color with an intensely marine aroma. Near-zero lactose prevents the milk from dispersing in seawater.

Nutritional Notes

Roughly 8–15× richer in fat than cow's milk. Very high in protein to support rapid muscle and organ development. Rich in omega-3 fatty acids including DHA, which is critical for the calf's brain development.

Minerals & Vitamins

High calcium and phosphorus content supports rapid skeletal growth. Significant vitamin A supports vision development in an aquatic environment. Contains elevated sodium and iodine relative to terrestrial mammal milks.

Unique Properties

Milk is actively ejected under muscular pressure — calves position their rostrum near the slit opening and receive short, forceful bursts. The extreme fat content allows maximum calories per nursing bout while the thick consistency resists dilution in seawater.