An endocast is the internal cast of a hollow object, often specifically used for an endocasts of the cranial vault

Cranial vault

The cranial vault is the space in the skull within the neurocranium, occupied by the brain. In humans, the size and shape of the brain, may be affected by the size of the vault as shown in craniometry, but studies relating it to intelligence have been ambivalent...

. Endocasts can be man-made for examining the properties of a hollow, inaccessible space, or occur naturally through fossil

Fossil

Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

isation.

Manmade casts

Endocasts of the inside of the neurocranium (braincase) is often made in paleoanthropology

Paleoanthropology

Paleoanthropology, which combines the disciplines of paleontology and physical anthropology, is the study of ancient humans as found in fossil hominid evidence such as petrifacted bones and footprints.-19th century:...

 to study brain structures and hemispheric specialization in extinct human ancestors

Hominina

The more anthropomorphic primates of the Hominini tribe are placed in the Hominina subtribe. Referred to as hominans, they are characterized by the evolution of an increasingly erect bipedal locomotion. The only extant species is Homo sapiens...

. While an endocast can not directly reveal brain structure, it can allow scientists to gauge the size of areas of the brain situated close to the surface, notably Wernicke's

Wernicke's area

Wernicke's area is one of the two parts of the cerebral cortex linked since the late nineteenth century to speech . It is involved in the understanding of written and spoken language...

 and Broca's area

Broca's area

Broca's area is a region of the hominid brain with functions linked to speech production.The production of language has been linked to the Broca’s area since Pierre Paul Broca reported impairments in two patients. They had lost the ability to speak after injury to the posterior inferior frontal...

s, responsible for interpreting and producing speech

Speech

Speech is the human faculty of speaking.It may also refer to:* Public speaking, the process of speaking to a group of people* Manner of articulation, how the body parts involved in making speech are manipulated...

. Traditionally, the casting material was some form of rubber

Rubber

Natural rubber, also called India rubber or caoutchouc, is an elastomer that was originally derived from latex, a milky colloid produced by some plants. The plants would be ‘tapped’, that is, an incision made into the bark of the tree and the sticky, milk colored latex sap collected and refined...

 or rubber-like material that could be sloshed around the empty cranial vault until it sets. The resulting hollow sphere could then be drained of air like a balloon and pulled out through foramen magnum. Today, scientists are increasingly utilizing computerized tomography scanning technology to create digital endocasts to avoid damaging valuable specimens.

Natural endocasts

Natural cranial endocasts are also known. The famous Taung Child

Taung Child

The Taung Child — or Taung Baby — is the fossilized skull of a young Australopithecus africanus individual. It was discovered in 1924 by quarrymen working for the Northern Lime Company in Taung, South Africa...

, the first Australopithecus

Australopithecus

Australopithecus is a genus of hominids that is now extinct. From the evidence gathered by palaeontologists and archaeologists, it appears that the Australopithecus genus evolved in eastern Africa around 4 million years ago before spreading throughout the continent and eventually becoming extinct...

found, consists of a natural endocast connected to the facial portion of the skull. It was the shape of the brain that allowed Raymond Dart

Raymond Dart

Raymond Arthur Dart was an Australian anatomist and anthropologist, best known for his involvement in the 1924 discovery of the first fossil ever found of Australopithecus africanus, an extinct hominid closely related to humans, at Taung in the North of South Africa in the province...

 to conclude that the fossil was that of a human relative rather than an extinct ape

Ape

Apes are Old World anthropoid mammals, more specifically a clade of tailless catarrhine primates, belonging to the biological superfamily Hominoidea. The apes are native to Africa and South-east Asia, although in relatively recent times humans have spread all over the world...

.

Mammal endocasts are particularly useful as the resemble the fresh brain with the dura mater

Dura mater

The dura mater , or dura, is the outermost of the three layers of the meninges surrounding the brain and spinal cord. It is derived from Mesoderm. The other two meningeal layers are the pia mater and the arachnoid mater. The dura surrounds the brain and the spinal cord and is responsible for...

 in place. Such "fossil brains" are known from several hundred different mammal species. More than a hundred natural cast of the cranial vault of Bathygenys

Bathygenys

Bathygenys is an extinct genus of terrestrial herbivore of the family Merycoidodontidae , endemic to North America during the Late Eocene-Early Oligocene subepochs existing for approximately ....

(a small Oreodont

Oreodont

Oreodons, sometimes called prehistoric "ruminating hogs," were a family of cud-chewing plant-eater with a short face and tusk-like canine teeth...

) alone are known, some having identifiable features down to the major gyri

Gyrus

A gyrus is a ridge on the cerebral cortex. It is generally surrounded by one or more sulci .-Notable gyri:* Superior frontal gyrus, lat. gyrus frontalis superior* Middle frontal gyrus, lat. gyrus frontalis medius...

. A natural cranial endocast of a Tyrannosaurus

Tyrannosaurus

Tyrannosaurus meaning "tyrant," and sauros meaning "lizard") is a genus of coelurosaurian theropod dinosaur. The species Tyrannosaurus rex , commonly abbreviated to T. rex, is a fixture in popular culture. It lived throughout what is now western North America, with a much wider range than other...

brain vault is also known, showing the animal had limited intelligence, but a well-developed sense of smell. The oldest known natural cranial endocast is a fossil fish brain from a Holocephalan

Holocephali

The subclass Holocephali is a taxon of cartilaginous fish, of which the order Chimaeriformes is the only surviving group.Holocephali has an extensive fossil record that starts during the Devonian period. However, most fossils are teeth, and the body forms of numerous species are not known, or, at...

, some 300 million years old.

Endocasts of other hollows

Endocasts fossils from animals with shells that easily disintegrate or dissolve, like the aragonite

Aragonite

Aragonite is a carbonate mineral, one of the two common, naturally occurring, crystal forms of calcium carbonate, CaCO3...

 shells of certain molluscs and the tests of sea urchin

Sea urchin

Sea urchins or urchins are small, spiny, globular animals which, with their close kin, such as sand dollars, constitute the class Echinoidea of the echinoderm phylum. They inhabit all oceans. Their shell, or "test", is round and spiny, typically from across. Common colors include black and dull...

s can often be encountered free from their mold fossil. A frequent form is the internal mold of brachiopod

Brachiopod

Brachiopods are a phylum of marine animals that have hard "valves" on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs. Brachiopod valves are hinged at the rear end, while the front can be opened for feeding or closed for protection...

s. In the quite symmetrical genus Pentamerus

Pentamerus

Pentamerus is a prehistoric genus of brachiopod that lived from the Silurian to the Middle Devonian in Asia, Europe, and North America.-External links:* in the Paleobiology Database...

the endocast resembles a vulva

Vulva

The vulva consists of the external genital organs of the female mammal. This article deals with the vulva of the human being, although the structures are similar for other mammals....

, giving these fossils the name Schamsteine ("shame stones") in German

German language

German is a West Germanic language, related to and classified alongside English and Dutch. With an estimated 90 – 98 million native speakers, German is one of the world's major languages and is the most widely-spoken first language in the European Union....

. The "Venus of Svinesund", a early mesolithic

Mesolithic

The Mesolithic is an archaeological concept used to refer to certain groups of archaeological cultures defined as falling between the Paleolithic and the Neolithic....

 Venus figurine

Venus figurines

Venus figurines is an umbrella term for a number of prehistoric statuettes of women portrayed with similar physical attributes from the Upper Palaeolithic, mostly found in Europe, but with finds as far east as Irkutsk Oblast, Siberia, extending their distribution to much of Eurasia, from the...

 from Norway

Norway

Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...

 is a re-worked brachiopod endocast. Endocasts are also known from snail shells and even from the stomach hollow of jellyfish

Jellyfish

Jellyfish are free-swimming members of the phylum Cnidaria. Medusa is another word for jellyfish, and refers to any free-swimming jellyfish stages in the phylum Cnidaria...

, a group that rarely leave fossil traces.

Man-made endocasts are sometimes made from blood vessels for medical or anatomical reasons. The blood vessel of an organ (e.g. 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,...

 or liver

Liver

The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...

) is injected with a resin

Resin

Resin in the most specific use of the term is a hydrocarbon secretion of many plants, particularly coniferous trees. Resins are valued for their chemical properties and associated uses, such as the production of varnishes, adhesives, and food glazing agents; as an important source of raw materials...

. When it is set, the organ itself is dissolved, leaving a three dimensional image of the blood supply to the organ.