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AVERAGE BRAIN WEIGHTS

Species

Weight

(gm)

Brain as Percent of Body Weight

Some Skulls

(from Skullduggery)





Primates




human male 1361 (~3 lb) 2.45% Homo sapiens skull
human female 1228 gm 2.38%
human newborn 350 - 400

Cro-Magnon Man

up to 160,000 years old

1450 (well within the modern range)

Neandertal Man (full-sized Homo sapiens)

up to 400,000 years old

1600
Neandertal Skull



Neandertal Skull
Homo floresiensis (only 3 ft tall) 380

Homo erectus 800 - 1200 1.69%
Homo habilis 700 1.71%
Australopithecus africanus 500 1.09%
Australopithecus afarensis 400 0.78% Australopithecus afarensis skull



Australopithecus afarensis skull

Brains compared to head size A human head is mostly full of brain. "Lower" animals do have a brain, but it is less dominant. Animals use their heads for other tasks than thinking; for example, for chewing and fighting.
chimpanzee male 440 0.84%
chimpanzee female 325 0.74%
gorilla male 570 0.33%
gorilla female 426 0.47%
orangutan 370 0.63%
baboon 137
Potar monkey 115 1.15%
rhesus monkey 179 2.63%
squirrel monkey 22

flying lemur 6

tree shrew 3





Others




sperm whale 7,800 gm

elephant 5,712 0.08%
bottle-nosed dolphin 1,500

walrus 1,126

camel 762

giraffe 680 0.13%
horse 655 0.13%
hippopotamus 582

polar bear 498

cow 423 0.09%
donkey 419 0.22%
tiger 264

lion 240

grizzly bear 234
pig 180 0.09%
sheep 175 0.32%
jaguar 157 0.16%
Brachiosaurus 154 0.0002%
wolf 119 0.33%
goat 115 0.42%
dog (beagle) 72

aardvark 72

Triceratops 70 0.0007%
kangaroo 56 0.16%
beaver 45

cat 25 0.78%
porcupine 25

marmot 17

rabbit 12 0.48%
platypus 9

alligator 8

squirrel 8

opossum 6

guinea pig 5.5 0.53%
fairy anteater 4.4

hedgehog 3.4

mole 3 2.46%
fairy armadillo 2.5

owl 2.2

rat 2 0.5%
elephant shrew 1.3

hamster 1 0.83%
mouse 0.4 1.74%
turtle 0.3

bull frog 0.24

viper 0.1

green lizard 0.08

from The Brain In the News, Dana Press, 3/03



© Harold F. Sears, Boulder, CO 80303; email: hfsears@isp01.net


Page last modified: 9/23/06

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