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How Do Other Mammals Nurse?

Days and nights we stayed up in the bracken pile, curled around one another, while I gave suck and licked and settled squabbles. They fed and slept and fed and squabbled, and I watched their small, sleek bodies plumping up with milk. Their eyes were shut, their small heads pushed into my flank, muzzles butting, jaws working hard in the rhythm of life, which is, at first, no more than suck and swallow.
From Fire, Bed & Bone, Henrietta Branford, Candlewick Press, 1998

There are over 4200 species of mammals on our planet. Mammals are animals that have a backbone, have hair or fur, are warm-blooded and whose females nurse their babies with milk. Each of these milks contains water, proteins, fats, carbohydrates, minerals, vitamins, cellular content and anti-infective agents. But each species of mammal produces a milk that is qualitatively different than the milk of other species, a milk that is perfectly suited for the growth and development of the offspring of that particular species.

The composition of the milk is related to the rate of growth of a species. Human milk is low in both protein and fat. Mammals with high fat content generally have young who need to form a thick coat of blubber to protect them from the cold. Mammals with a high protein content generally have young where growth is rapid and the young mature in a short time. Humans are among the slowest growing of all mammals.

Percent Protein and Fat in Milk

Species % Protein % Fat
Human 0.9 3.8
Talapoin monkey 2.1 3.0
Goat 2.9 4.50
Cow 3.41 3.7
African elephant 4.0 5.0
Black bear 7.0 25.1
Little brown bat 8.5 15.8
Gray seal 9.2 59.8
Cat 10.6 10.8
Blue whale 11.9 40.9
House mouse 12.5 27.0

One important feature of all non-human mammals is that they suckle their young until they are able to become independent. Breastfeeding is the crucial bridge between infancy and maturity. Here’s how some different mammals breastfeed...

Reprinted with permission from Breastfeeding at a Glance, By Dia L. Michels and Cynthia Good Mojab, M.S.with Naomi Bromberg Bar-Yam, Ph.D. Platypus Media, 2001, ISBN: 1-930775-05-9.

Adapted from: If My Mom Were A Platypus: Mammal Babies and their Mothers. By Dia L. Michels, Illustrated by Andrew Barthelmes, Platypus Media, 2005, ISBN: 1-930775-35-0.

This handout is available at: It may be copied and distributed without permission. For more information, contact Dia Michels at Dia, visit, call 1-877-PLATYPS (toll-free) or 1-202-546-1674.