Cranial capacity is a measure of the volume of the interior of the cranium (also called the braincase or brainpan) of those vertebrates who have both a cranium and a brain

Brain

The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...

. The most commonly used unit of measure is the cubic centimetre or cc. The volume of the cranium is used as a rough indicator of the size of the brain, and this in turn is used as a rough indicator of the potential intelligence of the organism. However, larger cranial capacity is not always indicative of a more intelligent organism, since larger capacities are required for controlling a larger body, or in some cases are an adaptive feature for life in a colder environment .
Neurological functions are determined more by the organization of the brain rather than the volume. Individual variability is also important when considering cranial capacity, for example the average Neanderthal cranial capacity for females is 1300 cc and 1600 for males (Stanford, 2009, 301).
In an attempt to use cranial capacity as an objective indicator of brain size, the encephalization quotient

Encephalization quotient

Encephalization Quotient , or encephalization level is a measure of relative brain size defined as the ratio between actual brain mass and predicted brain mass for an animal of a given size, which is hypothesized to be a rough estimate of the intelligence of the animal.This is a more refined...

 (EQ) was developed in 1973 by Harry Jerison. It compares the size of the brain of the specimen to the expected brain size of animals with roughly the same weight (Campbell et al., 2006, 346). This way a more objective judgement can be made on the cranial capacity of an individual animal.
Examples of cranial capacity:

• Orangutan
  Orangutan
  Orangutans are the only exclusively Asian genus of extant great ape. The largest living arboreal animals, they have proportionally longer arms than the other, more terrestrial, great apes. They are among the most intelligent primates and use a variety of sophisticated tools, also making sleeping...
  
  s: 275–500 cc
• Chimpanzee
  Chimpanzee
  Chimpanzee, sometimes colloquially chimp, is the common name for the two extant species of ape in the genus Pan. The Congo River forms the boundary between the native habitat of the two species:...
  
  s: 275–500 cc
• Gorilla
  Gorilla
  Gorillas are the largest extant species of primates. They are ground-dwelling, predominantly herbivorous apes that inhabit the forests of central Africa. Gorillas are divided into two species and either four or five subspecies...
  
  s: 340–752 cc
• Human
  Human
  Humans are the only living species in the Homo genus...
  
  s: 1100–1900 cc
• Neanderthal
  Neanderthal
  The Neanderthal is an extinct member of the Homo genus known from Pleistocene specimens found in Europe and parts of western and central Asia...
  
  s: 1200–1850 cc

Examples of early hominid

Hominidae

The Hominidae or include them .), as the term is used here, form a taxonomic family, including four extant genera: chimpanzees , gorillas , humans , and orangutans ....

s:

Taxon	Size (cc)	Number of specimens	Age (megannum)
Australopithecus afarensis Australopithecus afarensis Australopithecus afarensis is an extinct hominid that lived between 3.9 and 2.9 million years ago. A. afarensis was slenderly built, like the younger Australopithecus africanus. It is thought that A...	438	4	3.6–2.9
Australopithecus africanus Australopithecus africanus Australopithecus africanus was an early hominid, an australopithecine, who lived between 2–3 million years ago in the Pliocene. In common with the older Australopithecus afarensis, A. africanus was slenderly built, or gracile, and was thought to have been a direct ancestor of modern humans. Fossil...	452	7	3.0–2.4
Paranthropus boisei Paranthropus boisei Paranthropus boisei was an early hominin and described as the largest of the Paranthropus species...	521	1	2.3–1.4
Paranthropus robustus Paranthropus robustus Paranthropus robustus was originally discovered in Southern Africa in 1938. The development of P. robustus, namely in cranial features, seemed to be aimed in the direction of a "heavy-chewing complex"...	530	1	1.9–1.4
Homo habilis Homo habilis Homo habilis is a species of the genus Homo, which lived from approximately at the beginning of the Pleistocene period. The discovery and description of this species is credited to both Mary and Louis Leakey, who found fossils in Tanzania, East Africa, between 1962 and 1964. Homo habilis Homo...	612	6	1.9–1.6
Homo rudolfensis Homo rudolfensis Homo rudolfensis is a fossil human species discovered by Bernard Ngeneo, a member of a team led by anthropologist Richard Leakey and zoologist Meave Leakey in 1972, at Koobi Fora on the east side of Lake Rudolf in Kenya. The scientific name Pithecanthropus rudolfensis was proposed in 1978 by V. P...	700	1	2.4–1.6
Homo ergaster Homo ergaster Homo ergaster is an extinct chronospecies of Homo that lived in eastern and southern Africa during the early Pleistocene, about 2.5–1.7 million years ago.There is still disagreement on the subject of the classification, ancestry, and progeny of H...	871	3	1.9–1.7

See also

• Brain-to-body mass ratio
• Craniometry
• Human evolution
  Human evolution
  Human evolution refers to the evolutionary history of the genus Homo, including the emergence of Homo sapiens as a distinct species and as a unique category of hominids and mammals...
  
  
• Neuroscience and intelligence
  Neuroscience and intelligence
  Neuroscience and intelligence concerns the various neurological factors that may be responsible for the variation of intelligence within a species or between different species. Much of the work in this field is concerned with the variation in human intelligence, but other intelligent species such...