Homo habilis
   HOME

TheInfoList



''Homo habilis'' ("handy man") is an extinct
species In biology Biology is the natural science that studies life and living organisms, including their anatomy, physical structure, Biochemistry, chemical processes, Molecular biology, molecular interactions, Physiology, physiological mechanis ...

species
of
archaic human A number of varieties of '' Homo'' are grouped into the broad category of archaic humans in the period that precedes and is contemporary to the emergence of the earliest early modern humans (''Homo sapiens'') around 300 ka. Omo-Kibish I (Omo I) ...
from the
Early Pleistocene The Early Pleistocene is an unofficial sub-epoch in the international geologic timescale The geologic time scale (GTS) is a system of chronological dating that classifies Geology, geological strata (stratigraphy) in time. It is used by geologist ...
of East and South Africa about 2.3 to 1.65 million years ago (mya). Upon species description in 1964, ''H. habilis'' was highly contested, with many researchers recommending it be synonymised with ''
Australopithecus africanus ''Australopithecus africanus'' is an extinct Extinction is the termination of a kind of organism In biology, an organism (from Ancient Greek, Greek: ὀργανισμός, ''organismos'') is any individual contiguous system that emb ...

Australopithecus africanus
'', the only other early
hominin The Hominini form a Tribe (biology), taxonomic tribe of the subfamily Homininae ("hominines"). Hominini includes the extant genera ''Homo'' (humans) and ''Pan (genus), Pan'' (chimpanzees and bonobos), but excludes the genus ''Gorilla'' (gorillas). ...
known at the time, but ''H. habilis'' received more recognition as time went on and more relevant discoveries were made. By the 1980s, ''H. habilis'' was proposed to have been a human ancestor, directly evolving into ''
Homo erectus ''Homo erectus'' (meaning " upright man") is an extinct species In biology, a species is the basic unit of biological classification, classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is ofte ...

Homo erectus
'' which directly led to modern humans. This viewpoint is now debated. Several specimens with insecure species identification were assigned to ''H. habilis'', leading to arguments for splitting, namely into "'' H. rudolfensis''" and "'' H. gautengensis''" of which only the former has received wide support. Like contemporary ''Homo'', ''H. habilis'' brain size generally varied from . The body proportions of ''H. habilis'' are only known from two highly fragmentary skeletons, and is based largely on assuming a similar anatomy to the earlier
australopithecine Australopithecina or Hominina is a subtribe in the tribe Hominini. The members of the subtribe are generally '' Australopithecus'' ( cladistically including the genus, genera ''Homo'', ''Paranthropus'', and ''Kenyanthropus''), and it typically ...
s. Because of this, it has also been proposed ''H. habilis'' be moved to the
genus Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biolog ...
''
Australopithecus ''Australopithecus'' (, ; ; singular: australopith) is a genus of early hominins that existed in Africa during the Late Pliocene and Early Pleistocene. The genera ''Homo'' (which includes modern humans), ''Paranthropus'', and ''Kenyanthropus'' evo ...
'' as ''Australopithecus habilis''. However, the interpretation of ''H. habilis'' as a small-statured human with inefficient long distance travel capabilities has been challenged. The presumed female specimen OH 62 is traditionally interpreted as having been in height and in weight assuming australopithecine-like proportions, but assuming humanlike proportions she would have been about and . Nonetheless, ''H. habilis'' may have been at least partially
arboreal Arboreal locomotion is the locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them. Some animals may scale trees only occasionally, but others are exclusively arboreal. The habitats pose numer ...
like what is postulated for australopithecines. Early hominins are typically reconstructed as having thick hair and marked
sexual dimorphism Sexual dimorphism is the condition where the two sexes of the same species exhibit different characteristics beyond the differences in their sexual organs. The condition occurs in many animals and some plants. Differences may include secondary s ...
with males much larger than females, though relative male and female size is not definitively known. ''H. habilis'' manufactured the
Oldowan The Oldowan (or Mode I) was a widespread stone tool A stone tool is, in the most general sense, any tool A tool is an object that can extend an individual's ability to modify features of the surrounding environment. Although many animal ...

Oldowan
stone-tool
stone-tool
industry Industry may refer to: Economics * Industry (economics) In macroeconomics, an industry is a branch of an economy that produces a closely related set of raw materials, goods, or services. For example, one might refer to the wood industry ...
and mainly used tools in butchering. Early ''Homo'', compared to australopithecines, are generally thought to have consumed high quantities of meat and, in the case of ''H. habilis'', scavenged meat. Typically, early hominins are interpreted as having lived in
polygynous Polygyny (; from Neoclassical Greek πολυγυνία from πολύ- ''poly-'' "many", and γυνή ''gyne'' "woman" or "wife") is the most common and accepted form of polygamy, entailing the marriage of a man with several women. Most count ...
societies, though this is highly speculative. Assuming ''H. habilis'' society was similar to that of modern savanna
chimps The chimpanzee (''Pan troglodytes''), also known as the common chimpanzee, robust chimpanzee, or simply chimp, is a species of Hominidae, great ape native to the forest and savannah of tropical Africa. It has four confirmed subspecies and a fi ...
and
baboon Baboons are primate A primate ( ) (from Latin , from 'prime, first rank') is a eutherian mammal Mammals (from Latin language, Latin , 'breast') are a group of vertebrate animals constituting the class (biology), class Mammalia ...
s, groups may have numbered 70–85 members, with multiple males to defend against open savanna predators, such as big cats, hyenas and crocodiles. ''H. habilis'' coexisted with ''H. rudolfensis'', '' H. ergaster'' / ''H. erectus'' and ''
Paranthropus boisei ''Paranthropus boisei'' is a species In biology, a species is the basic unit of biological classification, classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest gro ...

Paranthropus boisei
''.


Taxonomy


Research history

The first recognised remains—
OH 7 OH 7 (Olduvai Hominid № 7), also nicknamed "Johnny's Child", is the type specimen In biology, a type is a particular specimen (or in some cases a group of specimens) of an organism In biology, an organism (from Ancient Greek, Greek: ...
, partial juvenile skull, hand, and foot bones dating to 1.75 million years ago (mya)—were discovered in
Olduvai Gorge The Olduvai Gorge or Oldupai Gorge in Tanzania is one of the most important paleoanthropology, paleoanthropological sites in the world; it has proven invaluable in furthering understanding of early human evolution. A steep-sided ravine in the Greg ...

Olduvai Gorge
, Tanzania, in 1960 by Jonathan Leakey. However, the actual first remains—OH 4, a molar—were discovered by the senior assistant of
LouisLouis may refer to: * Louis (given name) Louis is the French language, French form of the Old Frankish language, Old Frankish given name Clovis (given name), Chlodowig and one of two English language, English forms, the other being Lewis (given nam ...
and
Mary Mary may refer to: People * Mary (name) Mary is a feminine Femininity (also called womanliness or girlishness) is a set of attributes, behaviors, and roles generally associated with women and girls. Although femininity is socially constru ...

Mary
Leakey (Jonathan's parents), Heselon Mukiri, in 1959, but this was not realised at the time. By this time, the Leakeys had spent 29 years excavating in Olduvai Gorge for early
hominin The Hominini form a Tribe (biology), taxonomic tribe of the subfamily Homininae ("hominines"). Hominini includes the extant genera ''Homo'' (humans) and ''Pan (genus), Pan'' (chimpanzees and bonobos), but excludes the genus ''Gorilla'' (gorillas). ...
remains, but had instead recovered mainly other animal remains as well as the
Oldowan The Oldowan (or Mode I) was a widespread stone tool A stone tool is, in the most general sense, any tool A tool is an object that can extend an individual's ability to modify features of the surrounding environment. Although many animal ...

Oldowan
industry Industry may refer to: Economics * Industry (economics) In macroeconomics, an industry is a branch of an economy that produces a closely related set of raw materials, goods, or services. For example, one might refer to the wood industry ...
. The industry had been ascribed to ''
Paranthropus boisei ''Paranthropus boisei'' is a species In biology, a species is the basic unit of biological classification, classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest gro ...

Paranthropus boisei
'' (at the time "''Zinjanthropus''") in 1959 as it was the first and only hominin recovered in the area, but this was revised upon OH 7's discovery. In 1964, Louis, South African palaeoanthropologist Phillip V. Tobias, and British primatologist John R. Napier officially assigned the remains into the
genus Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biolog ...
''
Homo ''Homo'' () is the genus Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, virus ...

Homo
'' as, on recommendation by Australian anthropologist
Raymond Dart Raymond Arthur Dart (4 February 1893 – 22 November 1988) was an Australian anatomist and anthropologistAn anthropologist is a person engaged in the practice of anthropology. Anthropology is the study of aspects of humans within past and pre ...
, ''H. habilis'', the
specific nameSpecific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In Taxonomy (biology), taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), ...
meaning "able, handy, mentally skillful, vigorous" in
Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, known as Latium. Through the power of the Roman Republic, it became the ...

Latin
. The specimen's association with the Oldowan (then considered evidence of advanced cognitive ability) was also used as justification for classifying it into ''Homo''. OH 7 was designated the
holotype specimen A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several s ...
. After description, it was hotly debated if ''H. habilis'' should be reclassified into ''
Australopithecus africanus ''Australopithecus africanus'' is an extinct Extinction is the termination of a kind of organism In biology, an organism (from Ancient Greek, Greek: ὀργανισμός, ''organismos'') is any individual contiguous system that emb ...

Australopithecus africanus
'' (the only other early hominin known at the time), in part because the remains were so old and at the time ''Homo'' was presumed to have evolved in Asia (with the australopithecines having no living descendants). Also, the brain size was smaller than what
Wilfrid Le Gros Clark Sir Wilfrid Edward Le Gros Clark (5 June 1895 – 28 June 1971) was a British anatomist Anatomy (Greek ''anatomē'', 'dissection') is the branch of biology Biology is the natural science that studies life and living organisms, including ...
proposed in 1955 when considering ''Homo''. The classification ''H. habilis'' began to receive wider acceptance as more fossil elements and species were unearthed. In 1983, Tobias proposed that ''A. africanus'' was a direct ancestor of ''
Paranthropus ''Paranthropus'' is a genus of extinct hominin which contains two widely accepted species: '' P. robustus'' and '' P. boisei''. However, the validity of ''Paranthropus'' is contested, and it is sometimes considered to be synonym (taxonomy), sy ...
'' and ''Homo'' (the two were
sister taxa In phylogenetics, a sister group or sister taxon comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and taxon B are sister groups to eac ...
), and that ''A. africanus'' evolved into ''H. habilis'' which evolved into '' H. erectus'' which evolved into modern humans (by a process of
cladogenesis Cladogenesis is an evolutionary splitting of a parent species In biology, a species is the basic unit of biological classification, classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defi ...
). He further said that there was a major evolutionary leap between ''A. africanus'' and ''H. habilis'', and thereupon human evolution progressed gradually because ''H. habilis'' brain size had nearly doubled compared to australopithecine predecessors. Many had accepted Tobias' model and assigned
Late Pliocene Late may refer to: * LATE, an acronym which could stand for: ** Limbic-predominant age-related TDP-43 encephalopathy, a proposed form of dementia ** Local-authority trading enterprise, a New Zealand business law ** Local average treatment effect, ...
to
Early Pleistocene The Early Pleistocene is an unofficial sub-epoch in the international geologic timescale The geologic time scale (GTS) is a system of chronological dating that classifies Geology, geological strata (stratigraphy) in time. It is used by geologist ...
hominin remains outside the range of ''Paranthropus'' and ''H. erectus'' into ''H. habilis''. For non-skull elements, this was done on the basis of size as there was a lack of clear diagnostic characteristics. Because of these practices, the range of variation for the species became quite wide, and the terms ''H. habilis''
sensu stricto ''Sensu'' is a Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, known as Latium. Through the power of the Roman ...
("in the strict sense") and ''H. habilis''
sensu lato ''Sensu'' is a Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, known as Latium. Through the power of the Roman ...
("in the broad sense") were in use to include and exclude, respectively, more discrepant morphs. To address this, in 1985, English palaeoanthropologist Bernard Wood proposed that the comparatively massive skull KNM-ER 1470 from
Lake Turkana Lake Turkana (), formerly known as Lake Rudolf, is a lake in the Kenyan Rift Valley, in northern Kenya, with its far northern end crossing into Ethiopia. It is the world's largest permanent desert lake and the world's largest alkaline lake. ...

Lake Turkana
, Kenya, discovered in 1972 and assigned to ''H. habilis'', actually represented a different species, now referred to as ''
Homo rudolfensis ''Homo rudolfensis'' is a species of archaic human from the Early Pleistocene of East Africa about 2 million years ago (mya). Because ''H. rudolfensis'' coexisted with several other hominins, it is debated what specimens can be confidently assign ...

Homo rudolfensis
''. It is also argued that instead it represents a male specimen whereas other ''H. habilis'' specimens are female. Early ''Homo'' from South Africa have variously been assigned to ''H. habilis'' or ''H. ergaster'' / ''H. erectus'', but species designation has largely been unclear. In 2010, Australian archaeologist Darren Curoe proposed splitting off South African early ''Homo'' into a new species, "''
Homo gautengensis ''Homo gautengensis'' is a species name proposed by anthropologist Darren Curnoe in 2010 for South African hominin The Hominini form a Tribe (biology), taxonomic tribe of the subfamily Homininae ("hominines"). Hominini includes the extant gener ...
''". In 1986, OH 62, a fragmentary skeleton, was discovered by American anthropologist Tim D. White in association with ''H. habilis'' skull fragments, definitively establishing aspects of ''H. habilis'' skeletal anatomy for the first time, and revealing more ''
Australopithecus ''Australopithecus'' (, ; ; singular: australopith) is a genus of early hominins that existed in Africa during the Late Pliocene and Early Pleistocene. The genera ''Homo'' (which includes modern humans), ''Paranthropus'', and ''Kenyanthropus'' evo ...
''-like than ''Homo''-like features. Because of this, as well as similarities in dental adaptations, Wood and biological anthropologist Mark Collard suggested moving the species to ''Australopithecus'' in 1999. However, reevaluation of OH 62 to a more humanlike physiology, if correct, would cast doubt on this. The discovery of the 1.8 Ma Georgian
Dmanisi skulls The Dmanisi hominins, Dmanisi people or Dmanisi man were a population of Early Pleistocene Hominini, hominins whose fossils have been recovered at Dmanisi, Georgia. The fossils and stone tools recovered at Dmanisi range in age from 1.85–1.77 mi ...
in the early 2000s, which exhibit several similarities with early ''Homo'', has led to suggestions that all contemporary groups of early ''Homo'' in Africa, including ''H. habilis'' and ''H. rudolfensis'', are the same species and should be assigned to ''H. erectus''.


Classification

There is still no wide consensus as to whether or not ''H. habilis'' is ancestral to '' H. ergaster'' / ''H. erectus'' or is an offshoot of the human line, and whether or not all specimens assigned to ''H. habilis'' are correctly assigned or the species is an assemblage of different ''Australopithecus'' and ''Homo'' species. Nonetheless, ''H. habilis'' and ''H. rudolfensis'' generally are recognised members of the genus at the base of the family tree, with arguments for synonymisation or removal from the genus not widely adopted. Though it is now largely agreed upon that ''Homo'' evolved from ''Australopithecus'', the timing and placement of this split has been much debated, with many ''Australopithecus'' species having been proposed as the ancestor. The discovery of
LD 350-1 LD 350-1 is the earliest known specimen of the genus Genus (plural genera) is a taxonomic rank Taxonomy (general) is the practice and science of classification of things or concepts, including the principles that underlie such classification. T ...
, the oldest ''Homo'' specimen, dating to 2.8 mya, in the
Afar Region Afar Region (; aa, Qafar; am, ዓፋር ክልል), formerly known as Region 2, is a regional state in Northeastern Ethiopia Ethiopia (; am, ኢትዮጵያ, , aa, Itiyoophiyaa, gez, ኢትዮጵያ, om , Itoophiyaa, so, Itoobiya, ...
of Ethiopia may indicate that the genus evolved from '' A. afarensis'' around this time. The species LD 350-1 belongs to could be the ancestor of ''H. habilis'', but this is unclear. The oldest ''H. habilis'' specimen, A.L. 666-1, dates to 2.3 mya, but is anatomically more derived (has less ancestral, or basal, traits) than the younger OH 7, suggesting derived and basal morphs lived concurrently, and that the ''H. habilis'' lineage began before 2.3 mya. Based on 2.1-million-year-old stone tools from
Shangchen Shangchen () is a Lower Palaeolithic archaeological site An archaeological site is a place (or group of physical sites) in which evidence of past activity is preserved (either prehistoric Prehistory, also known as pre-literary history, ...
, China, ''H. habilis'' or an ancestral species may have dispersed across Asia. The youngest ''H. habilis'' specimen, OH 13, dates to about 1.65 mya.


Anatomy


Skull

It has generally been thought that brain size increased along the human line especially rapidly at the transition between species, with ''H. habilis'' brain size smaller than that of ''H. ergaster'' / ''H. erectus'', jumping from about in ''H. habilis'' to about in ''H. ergaster'' and ''H. erectus''. However, a 2015 study showed that the brain sizes of ''H. habilis'', ''H. rudolfensis'', and ''H. ergaster'' generally ranged between after reappraising the brain volume of OH 7 from to . This does, nonetheless, indicate a jump from australopithecine brain size which generally ranged from . The brain anatomy of all ''Homo'' features an expanded
cerebrum The cerebrum, telencephalon or endbrain, is the largest part of the brain A brain is an organ (biology), organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually c ...
in comparison to australopithecines. The pattern of striations on the teeth of OH 65 slanting right, which may have been accidentally self-inflicted when the individual was pulling a piece of meat with its teeth and the left hand while trying to cut it with a stone tool using the right hand. If correct, this could indicate right
handedness In human biology, handedness is the better, faster, or more precise performance or individual preference for use of a hand, known as the dominant hand. The incapable, less capable or less preferred hand is called the non-dominant hand. Right-ha ...

handedness
, and handedness is associated with major reorganisation of the brain and the lateralisation of brain function between the left and right hemispheres. This scenario has also been hypothesised for some Neanderthal specimens. Lateralisation could be implicated in tool use. In modern humans, lateralisation is weakly associated with language. The tooth rows of ''H. habilis'' were V-shaped as opposed to U-shaped in later ''Homo'', and the mouth jutted outwards (was
prognathic Prognathism is a positional relationship of the Human mandible, mandible or maxilla to the skeletal base where either of the jaws protrudes beyond a predetermined imaginary line in the coronal plane of the skull. In Dentistry, general dentistry, ...
), though the face was flat from the nose up.


Build

Based on the fragmentary skeletons OH 62 (presumed female) and KNM-ER 3735 (presumed male), ''H. habilis'' body anatomy has generally been considered to have been more apelike than even that of the earlier ''A. afarensis'' and consistent with an at least partially
arboreal Arboreal locomotion is the locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them. Some animals may scale trees only occasionally, but others are exclusively arboreal. The habitats pose numer ...
lifestyle in the trees as is assumed in australopithecines. Based on OH 62 and assuming comparable body dimensions to australopithecines, ''H. habilis'' has generally been interpreted as having been small-bodied like australopithecines, with OH 62 generally estimated at about in height and in weight. However, assuming longer, modern humanlike legs, OH 62 would have been about and , and KNM-ER 3735 about the same size. For comparison, modern human men and women in the year 1900 averaged and , respectively. It is generally assumed that pre-''H. ergaster'' hominins, including ''H. habilis'', exhibited notable
sexual dimorphism Sexual dimorphism is the condition where the two sexes of the same species exhibit different characteristics beyond the differences in their sexual organs. The condition occurs in many animals and some plants. Differences may include secondary s ...
with males markedly bigger than females. However, relative female body mass is unknown in this species. Early hominins, including ''H. habilis'', are thought to have had thick body hair coverage like modern non-human apes because they appear to have inhabited cooler regions and are thought to have had a less active lifestyle than (presumed hairless) post-''ergaster'' species. Consequently, they probably required thick body hair to stay warm. Based on dental development rates, ''H. habilis'' is assumed to have had an accelerated growth rate compared to modern humans, more like that of modern non-human apes.


Limbs

The arms of ''H. habilis'' and australopithecines have generally been considered to have been proportionally long and so adapted for climbing and swinging. In 2004, anthropologists Martin Haeusler and Henry McHenry argued that, because the
humerus The humerus (; ) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius (bone), radius and ulna, and consists of three sections. The humeral upper extremity of hu ...

humerus
to
femur The femur (, pl. ''femurs'' or ''femora'' ), or thigh bone, is the proximal Standard anatomical terms of location deal unambiguously with the anatomy of animals, including humans. Terms used generally derive from Latin or Greek language, Greek ro ...

femur
ratio of OH 62 is within the range of variation for modern humans, and KNM-ER 3735 is close to the modern human average, it is unsafe to assume apelike proportions. Nonetheless, the humerus of OH 62 measured long and the
ulna The ulna (''pl''. ulnae or ulnas) is a long bone found in the forearm that stretches from the elbow to the smallest finger, and when in Standard anatomical position, anatomical position, is found on the Anatomical terms of location, medial side of ...

ulna
(forearm) , which is closer to the proportion seen in chimpanzees. The hand bones of OH 7 suggest precision gripping, important in dexterity, as well as adaptations for climbing. In regard to the femur, traditionally comparisons with the ''A. afarensis'' specimen AL 288-1 have been used to reconstruct stout legs for ''H. habilis'', but Haeusler and McHenry suggested the more gracile OH 24 femur (either belonging to ''H. ergaster'' / ''H. erectus'' or ''P. boisei'') may be a more apt comparison. In this instance, ''H. habilis'' would have had longer, humanlike legs and have been effective long-distance travellers as is assumed to have been the case in ''H. ergaster''. However, estimating the unpreserved length of a fossil is highly problematic. The thickness of the limb bones in OH 62 is more similar to chimpanzees than ''H. ergaster'' / ''H. erectus'' and modern humans, which may indicate different load bearing capabilities more suitable for arboreality in ''H. habilis''. The strong
fibula The fibula or calf bone is a leg A leg is a weight-bearing and locomotive File:R707-loco-victorian-railways.jpg, upright=1.2, An Victorian Railways R class, R class steam locomotive number R707 as operated by the Victorian Railways of R ...

fibula
of OH 35 (though this may belong to ''P. boisei'') is more like that of non-human apes, and consistent with arboreality and vertical climbing. OH 8, a foot, is better suited for terrestrial movement than the foot of ''A. afarensis'', though still retains many apelike features consistent with climbing. However, the foot has projected toe bone and compacted mid-foot joint structures, which restrict rotation between the foot and ankle as well as at the front foot. Foot stability enhances the efficiency of force transfer between the leg and the foot and vice versa, and is implicated in the
plantar arch The plantar arch is a circulatory anastomosis formed from: * deep plantar artery, from the dorsalis pedis - a.k.a. dorsal artery of the foot * lateral plantar artery The plantar arch supplies the underside, or sole, of the foot. The plantar arch ...
elastic spring mechanism which generates energy while running (but not walking). This could possibly indicate ''H. habilis'' was capable of some degree of endurance running, which is typically thought to have evolved later in ''H. ergaster'' / ''H. erectus''.


Culture


Society

Typically, ''H. ergaster'' / ''H. erectus'' is considered to have been the first human to have lived in a
monogamous Monogamy ( ) is a form of Dyad (sociology), dyadic Intimate relationship, relationship in which an individual has only one Significant other, partner during their lifetime—alternately, only one partner at any one time (Monogamy#Serial monogamy ...
society, and all preceding hominins were
polygynous Polygyny (; from Neoclassical Greek πολυγυνία from πολύ- ''poly-'' "many", and γυνή ''gyne'' "woman" or "wife") is the most common and accepted form of polygamy, entailing the marriage of a man with several women. Most count ...
. However, it is highly difficult to speculate with any confidence the group dynamics of early hominins. The degree of sexual dimorphism and the size disparity between males and females is often used to correlate between polygyny with high disparity and monogamy with low disparity based on general trends (though not without exceptions) seen in modern primates. Rates of sexual dimorphism are difficult to determine as early hominin anatomy is poorly known, and are largely based on few specimens. In some cases, sex is arbitrarily determined in large part based on perceived size and apparent
robustnessRobustness is the property of being strong and healthy in constitution. When it is transposed into a system, it refers to the ability of tolerating perturbations that might affect the system’s functional body. In the same line ''robustness'' can be ...
in the absence of more reliable elements in sex identification (namely the pelvis). Mating systems are also based on dental anatomy, but early hominins possess a mosaic anatomy of different traits not seen together in modern primates; the enlarged cheek teeth would suggest marked size-related dimorphism and thus intense male–male conflict over mates and a polygynous society, but the small canines should indicate the opposite. Other selective pressures, including diet, can also dramatically impact dental anatomy. The spatial distribution of tools and processed animal bones at the FLK Zinj and PTK sites in Olduvai Gorge indicate the inhabitants used this area as a communal butchering and eating grounds, as opposed to the
nuclear family A nuclear family, elementary family or conjugal family is a family group consisting of parents and their children (one or more). It is in contrast to a single-parent family, the larger extended family, or a family with more than two parents. Nuclea ...
system of modern hunter gatherers where the group is subdivided into smaller units each with their own butchering and eating grounds. The behaviour of early ''Homo'', including ''H. habilis'', is sometimes modelled on that of savanna chimps and
baboon Baboons are primate A primate ( ) (from Latin , from 'prime, first rank') is a eutherian mammal Mammals (from Latin language, Latin , 'breast') are a group of vertebrate animals constituting the class (biology), class Mammalia ...
s. These communities consist of several males (as opposed to a
harem Harem ( ar, حريم ''ḥarīm'', "a sacred inviolable place; harem; female members of the family") properly refers to domestic spaces that are reserved for the women of the house in a Muslim family. A harem may house a man's wife or wives, the ...
society) in order to defend the group on the dangerous and exposed habitat, sometimes engaging in a group display of throwing sticks and stones against enemies and predators. The left foot OH 8 seems to have been bitten off by a crocodile, possibly '' Crocodylus anthropophagus'', and the leg OH 35, which either belongs to ''P. boisei'' or ''H. habilis'', shows evidence of
leopard The leopard (''Panthera pardus'') is one of the five extant species In biology Biology is the natural science that studies life and living organisms, including their anatomy, physical structure, Biochemistry, chemical processes, Mole ...

leopard
predation. ''H. habilis'' and contemporary hominins were likely predated upon by other large carnivores of the time, such as (in Olduvai Gorge) the hunting hyena ''Chasmaporthetes nitidula'', and the saber-toothed cats ''
Dinofelis ''Dinofelis'' is a genus of extinct sabre-toothed cats belonging to the tribe Metailurini. They were widespread in Europe Europe is a continent A continent is one of several large landmasses. Generally identified by convention (nor ...

Dinofelis
'' and ''
Megantereon ''Megantereon'' was a genus of prehistoric machairodontine saber-toothed cat that lived in North America North America is a continent entirely within the Northern Hemisphere and almost all within the Western Hemisphere. It can also ...
''. In 1993, American palaeoanthropologist Leslie C. Aiello and British evolutionary psychologist
Robin Dunbar Robin Ian MacDonald Dunbar (born 28 June 1947) is a British anthropologistAn anthropologist is a person engaged in the practice of anthropology. Anthropology is the study of aspects of humans within past and present Society, societies. Social ant ...
estimated that ''H. habilis'' group size ranged from 70–85 members—on the upper end of chimp and baboon group size—based on trends seen in
neocortex The neocortex, also called the neopallium, isocortex, or the six-layered cortex, is a set of layers of the mammalian Mammals (from Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the In ...

neocortex
size and group size in modern non-human primates. ''H. habilis'' coexisted with ''H. rudolfensis'', ''H. ergaster'' / ''H. erectus'', and ''P. boisei''. It is unclear how all of these species interacted. To explain why ''P. boisei'' was associated with Olduwan tools despite not being the knapper (the one who made the tools), Leakey and colleagues, when describing ''H. habilis'', suggested that one possibility was ''P. boisei'' was killed by ''H. habilis'', perhaps as food. However, when describing ''P. boisei'' five years earlier, Louis Leakey said, "There is no reason whatever, in this case, to believe that the skull represents the victim of a cannibalistic feast by some hypothetical more advanced type of man."


Diet

It is thought ''H. habilis'' derived meat from scavenging rather than hunting (scavenger hypothesis), acting as a confrontational scavenger and stealing kills from smaller predators such as
jackal Jackals are medium-sized omnivorous mammals of the Canina (subtribe), subtribe Canina, which also includes wolves and the domestic dog, among other species. While the word "jackal" has historically been used for many small canines, in modern ...

jackal
s or
cheetah The cheetah (''Acinonyx jubatus'') is a large cat native to Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) includin ...

cheetah
s. Fruit was likely also an important dietary component, indicated by dental erosion consistent with repetitive exposure to acidity. Based on dental microwear-texture analysis, ''H. habilis'' (like other early ''Homo'') likely did not regularly consume tough foods. Microwear-texture complexity is, on average, somewhere between that of tough-food eaters and leaf eaters (
folivore In zoology, a folivore is a herbivore that specializes in eating leaves. Mature leaves contain a high proportion of hard-to-digest cellulose, less energy than other types of foods, and often toxic compounds.Jones, S., Martin, R., & Pilbeam, D. (199 ...
s), and points to an increasingly generalised and
omnivorous An omnivore () is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nutrien ...
diet. It is typically thought that the diets of ''H. habilis'' and other early ''Homo'' had a greater proportion of meat than ''Australopithecus'', and that this led to brain growth. The main hypotheses regarding this are: meat is energy- and nutrient-rich and put evolutionary pressure on developing enhanced cognitive skills to facilitate strategic scavenging and monopolise fresh carcasses, or meat allowed the large and calorie-expensive ape gut to decrease in size allowing this energy to be diverted to brain growth. Alternatively, it is also suggested that early ''Homo'', in a drying climate with scarcer food options, relied primarily on underground
storage organ A storage organ is a part of a plant Plants are predominantly photosynthetic eukaryotes of the Kingdom (biology), kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fung ...
s (such as
tuber Tubers are enlarged structures used as storage organs for nutrients in some plants. They are used for the plant's perennation (survival of the winter or dry months), to provide energy and nutrients for regrowth during the next growing season, and ...
s) and food sharing, which facilitated social bonding among both male and female group members. However, unlike what is presumed for ''H. ergaster'' and later ''Homo'', short-statured early ''Homo'' are generally considered to have been incapable of endurance running and hunting, and the long and ''Australopithecus''-like forearm of ''H. habilis'' could indicate early ''Homo'' were still arboreal to a degree. Also, organised
hunting and gathering A hunter-gatherer is a human living in a society in which most or all food is obtained by foraging (collecting wild plants and pursuing Wildlife, wild animals). Hunter-gatherer societies stand in contrast to agriculture, agricultural societies, wh ...
is thought to have emerged in ''H. ergaster''. Nonetheless, the proposed food-gathering models to explain large brain growth necessitate increased daily travel distance. It has also been argued that ''H. habilis'' instead had long, modern humanlike legs and was fully capable of effective long distance travel, while still remaining at least partially arboreal. Large
incisor Incisors (from Latin ''incidere'', "to cut") are the front teeth A tooth (plural teeth) is a hard, calcification, calcified structure found in the jaws (or mouths) of many vertebrates and used to Mastication, break down food. Some animals, part ...
size in ''H. habilis'' compared to ''Australopithecus'' predecessors implies this species relied on incisors more. The of ''H. habilis'' and other early ''Homo'' are thicker than those of modern humans and all living apes, more comparable to ''Australopithecus''. The mandibular body resists torsion from the
bite force Bite force quotient (BFQ) is the regression of the quotient In arithmetic Arithmetic (from the Ancient Greek, Greek wikt:en:ἀριθμός#Ancient Greek, ἀριθμός ''arithmos'', 'number' and wikt:en:τική#Ancient Greek, τική w ...
or chewing, meaning their jaws could produce unusually powerful stresses while eating. The greater molar cusp (anatomy), cusp relief in ''H. habilis'' compared to ''Australopithecus'' suggests the former used tools to fracture tough foods (such as pliable plant parts or meat), otherwise the cusps would have been more worn down. Nonetheless, the jaw adaptations for processing mechanically challenging food indicates technological advancement did not greatly affect diet.


Technology

''H. habilis'' is associated with the Lower Paleolithic, Early Stone Age Oldowan stone tool industry. Individuals likely used these tools primarily to butcher and skin animals and crush bones, but also sometimes to saw and scrape wood and cut soft plants. Knappers appear to have carefully selected lithic cores and knew that certain rocks would break in a specific way when struck hard enough and on the right spot, and they produced several different types, including chopper (archaeology), choppers, polyhedrons, and discoids. Nonetheless, specific shapes were likely not thought of in advance, and probably stem from a lack of standardisation in producing such tools as well as the types of raw materials at the knappers' disposal. For example, spheroids are common at Olduvai which features an abundance of large and soft quartz and quartzite pieces, whereas Koobi Fora lacks spheroids and provides predominantly hard basalt lava rocks. Unlike the later Acheulean culture invented by ''H. ergaster'' / ''H. erectus'', Oldowan technology does not require planning and foresight to manufacture, and thus does not indicate high cognition in Oldowan knappers, though it does require a degree of coordination and some knowledge of mechanics. Oldowan tools infrequently exhibit retouch (lithics), retouching and were probably discarded immediately after use most of the time. The Olduwan was first reported in 1934, but it was not until the 1960s that it become widely accepted as the earliest culture, dating to 1.8 mya, and as having been manufactured by ''H. habilis''. Since then, more discoveries have placed the origins of material culture substantially backwards in time, with the Oldowan being discovered in Ledi-Geraru and Gona, Ethiopia, Gona in Ethiopia dating to 2.6 mya, perhaps associated with the evolution of the genus. Australopithecines are also known to have manufactured tools, such as the 3.3 Ma Lomekwi stone tool industry, and some evidence of butchering from about 3.4 mya. Nonetheless, the comparatively sharp-edged Oldowan culture was a major innovation from australopithecine technology, and it would have allowed different feeding strategies and the ability to process a wider range of foods, which would have been advantageous in the changing climate of the time. It is unclear if the Oldowan was independently invented or if it was the result of hominin experimentation with rocks over hundreds of thousands of years across multiple species. In 1962, a circle made with volcanic rocks was discovered in Olduvai Gorge. At intervals, rocks were piled up to high. Mary Leakey suggested the rock piles were used to support poles stuck into the ground, possibly to support a windbreak or a rough hut. Some modern-day nomadic tribes build similar low-lying rock walls to build temporary shelters upon, bending upright branches as poles and using grasses or animal hide as a screen. Dating to 1.75 mya, it is attributed to some early ''Homo'', and is the oldest-claimed evidence of architecture.


See also


References


External links


Reconstructions of ''H. habilis''
by John Gurche
Archaeology Info

''Homo habilis''
– The Smithsonian Institution's Human Origins Program
Human Timeline (Interactive)
– Smithsonian Institution, Smithsonian, National Museum of Natural History (August 2016). {{portal bar, Evolutionary biology, Science 1962 archaeological discoveries Lower Paleolithic Early species of Homo Hominini Transitional fossils Mammals described in 1964 Fossil taxa described in 1964 Prehistoric Tanzania Pleistocene mammals of Africa Prehistoric Kenya Pleistocene primates Taxa named by Richard Leakey