Some Land Mammals >30 LBs (closest to our evolutionary tree)
AnimalLife SpanAverage Life SpanGestation Period
(months)
Avg # of Babies
at Birth
% Milk Protein
(by weight)
Human73.173.1910.9%
Elephant60-70652211.9%
Rhino40-50451611.5%
Hippo40-5045811.8%
Camel40-50451313.1%
Chimp40-5045811.6%
Orangutan30-50408.511.3%
Gorilla35-4037.58.511.8%
Donkey25-35301211.7%
Horse25-3027.51112.1%
Bear Polar20-30258210.0%
Bear Grizzly20-3025728.5%
Bear Panda20-302551.56.8%
Baboon20-3025611.8%
Zebra20-2522.51212.2%
Moose15-2520817.5%
Llama15-252011.513.5%
Bear Black15-2520727.5%
Buffalo15-25201014.5%
Cow15-2017.5913.4%
Deer10-20156.528.0%
Pig12-18153.885.5%
Leopard12-1714.53.52.59.5%
Tiger10-1512.53.539.0%
Lion10-14123.538.5%
Elk10-1311.58.517.9%
Dog10-1311.5257.5%
Wolf6-87258.0%
We like other Herbivores have a long life span.
Like other Herbivores, our long (9 months) gestation period allows more time for a single human baby's brain to develop and grow in the womb. Proof: The rate of mental retardation is higher among premature babies and twins. Source
Our Brain grows fastest from 0-6 months on Human Breast Milk
which has the lowest % protein (by weight) of all Herbivores.
Cow's Milk has 3.5 times more protein than human breast milk.