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Cetacean Anatomy · Interactive Diagram

Whale Mammary System
External & Cross-Section View

Blowhole (naris) 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

Each nipple sits inside a protective mammary slit, keeping the body hydrodynamic. The slits open only during nursing.

Milk ejection

Powerful muscles surrounding the gland actively squirt high-fat milk (up to 60% fat) directly into the calf's mouth.

Paired glands

Whales have two mammary glands, one behind each slit, positioned on the underside between the navel and flukes.

Streamlined design

Unlike land mammals, nothing protrudes. The entire system sits flush with the belly to minimize drag.

Milk Profile

35–50%
Fat
10–12%
Protein
1–2%
Lactose
~2,500 kcal/L
Energy
Calf Nursing Bout
~30 L
Seconds-long bursts, several times/hr
~75,000 kcal per bout
vs
Human Serving
240 mL
1 standard cup
~600 kcal per cup

Taste & Texture

Extremely thick, paste-like consistency often compared to toothpaste or condensed cream. Fishy, oily flavor with a strong marine aroma. Not palatable to most humans.

Nutritional Notes

Among the fattiest milk of any mammal — up to 10x the fat of cow's milk. Very high in calcium (~340 mg/100g) for rapid bone development. Rich in omega-3 fatty acids. Virtually no lactose, so it won't curdle in seawater.

Minerals & Vitamins

High phosphorus and magnesium content supports skeletal growth. Contains significant vitamin A and D. Sodium levels are elevated compared to terrestrial mammals, reflecting the marine environment.

Unique Properties

Milk is actively squirted under muscular pressure — calves don't suckle in the traditional sense. The extreme fat content keeps milk cohesive underwater and delivers maximum calories per nursing bout, which lasts only seconds.