AVERAGE BRAIN WEIGHTS

Species	Weight (gm)	Brain as Percent of Body Weight	Some Skulls (from Skullduggery)

Primates
human male	1361 (~3 lb)	2.45%
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

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%

		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

Species