Chapter 23 - The Bipedal Apes
“The primate who first walked bipedally
Perhaps did not do so too steadily.
Using two legs, but not four,
Brought him rewards by the score,
And so now we all do it quite readily.”
In this chapter, we cover our possible earliest primate ancestors and their possible evolution into bipedal apes, the seminal step on the road to becoming man. 1
As explained in Chapter 1, walking on two feet created the opportunity to cash in on a larger brain by making grasping hands, forward-directed eyes, pair bonding, and cooperation pay off big time.
Although OoE is primarily concerned with the evolution of modern man from the first species of Homo, there are reasons why the entire evolution of man, from a primitive primate onward, may have occurred in Eurasia, not Africa. (Begun, 1997).
The First Primates
Before there were any bipedal apes, tree-dwelling mammals were being selected for increased intelligence in both Africa and Asia. Thus, it is reasonable to assume that the Asian tree-dwelling mammals would be at least as competent as the African tree-dwelling mammals and that African tree-dwelling mammals could not have left Africa and replaced Asian tree-dwelling mammals.
Figure 23-1 (University of Maryland) shows two incredibly cute SE Asian tree shrews. 2 Note the more muscular legs compared to the arms, and the vertical posture. Climbing trees means that most of the weight is on the legs, resulting in “the emancipation of the forearms,” which are now free to grasp, examine, and hold. (Howells, 1959, p. 124). In a grasping tree mammal, individuals who had smaller claws were selected because they interfered less with grasping and touching; eventually these smaller claws became nails in the primates. (Id., p.123).
The first true primates, Teilhardina, originated in Asia about 55.5 mya, then spread to Europe and North America; 3 Bahinia, at the base of the OoE tree (Fig. IV-1) lived 40 mya and is found only in Asia. Another fossil, a 45 million year old tarsier, similar to the tarsiers that still live today on Madagascar, was found in China. 4 Some scientists have proposed a “tarsier theory” of bipedalism, that bipedal hominoids evolved from a tarsier-like mammal that clung in a vertical position to the trunk of trees as the tarsier in Figure 23-2 is doing; note its large thigh muscles.
The absence of horizontal branches (e.g., bamboo in the Asian tropics) may have favored animals that were more adept in a vertical position. When those animals moved into trees with horizontal branches that could support more weight, they could become heavier and move by hanging from the branches by their arms, still retaining their vertical posture. 5
Note that the eyes of the tarsier (Figure 23-2) are in the front of the head, both eyes looking forward, as in a species that is predominantly a predator, rather than on the side of the head, as in a species that is predominately prey, e.g., the tree shrews in Figure 23-1. The tarsier has large eyes because it is nocturnal and a small nose because it relies more on sight than on smell. The eyes of an animal that is habitually in a vertical posture are directed at a 90° angle to its spine, not at a 180° angle as in a quadruped; thus, the foramen magnum (Fig. 9-18) is already in the center of the skull and it does not have to migrate there as it would in a quadruped. 6
|Figure 23-3 ||Figure 23-4
Noting that the two most primitive monkey-like fossils were found in Asia (Jaeger, 1999), we move on to the apes. Although today there are no apes in Europe (the Barbary “apes” on Gibraltar are tailless monkeys) and the orangutans and gibbons are the only apes in Asia, nevertheless “ ... chimp-like apes [once lived] in Europe and Asia as well as in Africa; orangs [lived] in China and India…” (Howells, 1959, p. 107). Where the first ape evolved is not certain, though it may well have been Europe. 7
About 20 to 9 mya, the 2 foot tall Dryopithecus (“woodland ape”) was living in Africa, Europe, 8 and Asia. It was not bipedal, but it was believed to have been partially upright (Moya-Sola, 1996). Unlike chimpanzees and gorillas, it did not develop the anatomy for knuckle-walking. Figure 23-3 shows a Dryopithecus skull and Figure 23-4 shows a reconstruction. 9 Again, note the large, round, forward-directed eye sockets. The large canine teeth are primitive, 10 but Dryopithecus did have a “Y-5” dental pattern (Fig. 23-5), the same as the great apes and humans, 11 as well as thick enamel, which humans and orangutans have, but African apes do not have. Other aspects of its teeth were also more human than ape-like and its limbs have been described as orangutan-like. (Schwartz, 2005, pp. 29, 49). Dryopithecus was very similar to Sivapithecus, an ape that lived 12.5 to 8.5 mya in what is now India and Pakistan, whose cheek teeth also had thick enamel. 12
After Dryopithecus came Ramapithecus, another human and orangutan-like ape, 13 also with thick tooth enamel. It is dated about 12 mya and was found in India and East Africa. (Schwartz, 2005, pp. 48-49, 138). Thus, tropical India may be a more likely location for the first human-like apes than tropical Africa.
The Cookie Monster
The first (at least partially) 14 bipedal ape was 3’7” tall Oreopithecus bambolii (“Oreo,” the Cookie Monster, aka the “Swamp Ape”), who lived in swamps, the margins of shallow lakes, and forests near streams and rivers. 15 Oreo’s bones have been found on the island of Tuscany-Sardinia in Italy and also in SW Asia and NE Africa. Oreo, Figure 23-6, 16 lived from 11.2 to 3.4 mya, 17 overlapping with Australopithecus. Oreo lacked a chin and external nose bones, and the brow ridges were heavy, but he was starting to look a little bit human. (Schwartz, 2005, p. 97).
Oreo had a number of curiously humanlike traits in its teeth, jaws, skull, and hipbone, and its hand was human-like. (Moyà-Solà, 1999). Oreo is also favored as an ancestor of humans because he lived in West Asia (Iran), which is not only centrally located and just south of where georgicus was found, but it is where other important advances occurred, e.g., agriculture, early civilizations.
Feeding on aquatic plants and animals is dangerous if crocodiles are present, 18 and even today chimpanzees wisely avoid entering water. A European primate such as Oreo, however, may have lived north of the croc range, where the water was safe and aquatic life provided a rich source of the essential fatty acids needed for growing a larger brain. (Crawford, 2000). Oreo had not yet evolved all of the anatomical changes needed for easy bipedalism on land, but wading on two feet in the water facilitated the transition to land because the water reduced the weight on the legs and made it easier to balance. (Kuliukas, 2001). Aquatic bipedalism also kept the head above the water, gave a better view of what was underneath the water, and permitted feeding in deeper water. 19
| Oreo || Australopithecus
Because Australopithecus (“southern ape”) was not only fully bipedal, but also a long lasting and widespread genus with at least six species, ramidus, afarensis, 20 garhi, africanus, anamensis, and robustus, it is Oreo’s logical descendant; it evolved when Oreo, the Swamp Ape, left the water. Figure 23-7 compares the skulls of 10 mya Oreo and 3 mya Australopithecus africanus and shows how similar they are. (Howells, 1959, pp. 129 and 117). Various species of Australopithecus lived from 4 to 1.2 mya. (Wikipedia, “Australopithecus”). The jaws of both skulls occupy a large portion of the face, but Oreo has larger canines and Australopithecus has more prognathism. 21 Australopithecus had more human-like teeth than the chimpanzee, suggesting that the split between Pan (chimpanzee) and Homo (man) occurred prior to Australopithecus. (Figure IV-1). “… australopiths are basically oranglike in their teeth and in many aspects of their skulls….” (Schwartz, 2005, p. 215, 245-246). Like Oreo, Australopithecus (Figure 23-8) 22 had heavily enameled teeth (Howells, 1959, pp 117-118), a trait of humans, but not African apes. The robust form, A. robustus) had a saggital keel, similar to that of the gorilla. 23
The pelvis and leg bones closely resemble those of modern man, leaving no doubt that they walked on two feet. They were between about 107 cm (3'6") and 152 cm (5'0") tall with very strong bones. The finger and toe bones are curved and proportionally longer than in humans, but the hands are similar to human hands in most other details. Females were substantially smaller than males (sexual dimorphism). Australopithecus left small, knapped stone tools dated at 3.5 mya. (Coppens, 2004, p. 51). Cranial capacity varied from about 375 to 550 cc. The nose is more prominent, the brow ridges less so, but (minus the hair) the face is not much different from the reconstruction of Oreo in Figure 23-6.
Although different species of Australopithecus lived in Africa for 2.8 million years, evidence for their presence in Europe and Asia is, as yet, hard to come by. Their long presence and many species suggest that the absence of Australopithecus fossils outside of Africa is due to our failure to find their remains, rather than to their failure to occupy Eurasia. 24 Their presence in Africa could easily be due to their migration there. 25
Knuckle-Walkers or Palm-Walkers?
African apes (chimps and gorillas) walk on feet and knuckles (Fig. 23-9). 26 Asian apes (e.g., the orangutan) do not knuckle-walk – they walk on their palms. So, determining whether humans are more similar to African knuckle-walking chimps or to Asian brachiating orangutans should help answer the question of whether man had an African origin or an Asian origin. 27
Although palm-walking does not require any anatomical changes, knuckle- walking requires specialized changes to the fingers, wrist, and forearm bones so that the animal can lock its wrists to support the weight of its upper body. 28 Figure 23-10 is a graph, the purpose of which is to show whether Australopithecus was closer in wrist bone structure to the knuckle-walking African apes or to the palm-walking Asian orangs. 29 The two ellipses at the top center cover the wrist characteristics for the gorilla and “Pan,” the knuckle-walking chimp, the ellipse at the lower left is for the orangutan (“Pongo”), and the ellipse in the lower center is for man (“Homo”). The graph shows that early Australopithecus (“ER 20419” and “AL 288-1v and 1g”) were closer to the knuckle-walkers than to the orangutan, but the later Paranthropus (“SKX 3602,” now considered to be an Australopithecus) and the later Australopithecus (“Stw 46”) were about equidistant from Pan and Pongo. Note that the Pongo ellipse overlaps substantially with the Homo ellipse, but there is no overlap between the Pan or Gorilla ellipses with the Homo ellipse.
The authors of the article that graph is from conclude that man’s predecessors were knuckle-walkers who lost knuckle-walking adaptations, 30 but concede that “vertical climbing adaptation may be ‘preadaptive’ to bipedalism.” That is, man’s ancestors may have had a vertical posture in trees, similar to the tarsier (Fig. 23-2). If, as the authors conclude, humans evolved from a knuckle-walking African ape, they would have had to have lost the specialized anatomical adaptations that chimpanzees and gorillas have for knuckle-walking. However, Rule 3 (Chap. 4) says that animals evolve from a more generalized form to a more specialized form, seldom, if ever, the reverse. Humans are the most generalized primates, which suggests that they did not evolve from African apes, who are specialized for knuckle-walking.
No bipedal ape survives today, 31 but additional light can be thrown on the answer to the question of whether man descended from a bipedal African ape or a bipedal Eurasian ape by comparing man to African chimpanzees (the common chimp and the bonobo) and to the Asian orangutan.
Most paleoanthropologists have concluded that man descended from an ancestor of the chimpanzees, rather than from an ancestor of the orangutans, 32 because the genetic distance between humans and chimpanzees is less than the genetic distance between humans and orangutans. Genetic distance comparisons suggest the tree shown in Figure 23-11. However, it is possible that man descended from an Asian ape even though the chimp-human genetic distance is less than the orangutan-human genetic distance. In Figure 23-11, man and orangutan are in completely different lineages. In Figure 23-12, however, there is a split (“C/H LCA”) into a chimp lineage (line C) and a Homo lineage (lines H). 33 Genetic changes in the Homo lineage (line O-H) that occurred prior to the orang/Homo LCA (“O/H LCA”), ended up in both the subsequent Homo lineage (line H) and in the orangutan lineage (line O). In other words, the LCA of humans and orangutans is more recent than the LCA of humans and chimps, but still a very long time ago. (Line length is not proportional to genetic distance in these trees.)
|Figure 23-11 ||Figure 23-12
The reason that the genetic distance between the chimpanzees and humans (Hss) is less than the genetic distance between the orangutan and humans is that after the orang/Homo LCA, a population in the Homo lineage migrated into Africa (line I) and interbred with a population in the chimp lineage. 34 Evidence of interbreeding between the chimp and Homo lineages has recently been found. 35 Neither of the ancestral species that actually did the interbreeding is living today. (Since chimps today live only in Africa, it is likely that both the chimp ancestors and the Homo ancestors that interbred were living in Africa.)
The Homo ancestor that interbred with the chimp ancestor was at least a bipedal ape and may have even been an Australopithecus. 36 Thus, the chimp lineage received DNA from the Homo linage, and that DNA would be more recent DNA than the DNA that the human and orangutan lineages shared at the time of the orang/Homo LCA.
Since it is more often the males of the more advanced population that interbreed with the females of the less advanced population, the DNA should have flowed mostly from the Homo lineage to the chimp lineage and not the reverse. 37 After the split in the chimp-Homo lineages, any genetic changes that occurred in the chimp lineage (line C) never got into the Eurasian Homo lineage (line H) because, except for slavery, no hominids are known to have left Africa and interbred with the Eurasian Homo lineage.
When orangutans come down to the ground, they walk on feet and palms with bent fingers, but also bipedally (Fig. 23-13), 38 while African apes walk on their feet and knuckles (Fig. 23-9), though bonobos also walk bipedally for short distances.
The sacral index (Table 9-3) increases to facilitate bipedalism; in the orangutan it is 87, significantly greater than in the chimpanzee (77), and is closer to humans (Negroes = 91.4), suggesting that the orangutan is more bipedal and more human-like than the chimpanzee. 39 The femur of the orangutan is also more human-like than that of the African apes. (Harmon,
Take a look at this remarkable picture (Figure 23-14) of a female bonobo. The body of this bonobo looks so human it is difficult to believe that it is a chimpanzee. 40 Is it unreasonable to suggest that after the bonobo’s ancestors split from the common chimpanzee’s ancestors they interbred with a bipedal ape, perhaps a bipedal swamp ape 41 that had migrated into Africa? Note the muscular thighs. To paraphrase a Nancy Sinatra song, “these thighs are made for walking.” Although the bonobo is a knuckle-walker, like the common chimpanzee, its legs are longer 42 and it walks bipedally about a fourth of the time, more easily, with a straighter back, and for longer distances than the common chimp. 43 Bonobos have many human-like traits, including neoteny, a flatter face, a higher forehead, narrower body, pinker lips, longer hair, and smaller ears. Unlike common chimps, female bonobos have more prominent breasts and are sexually receptive throughout most of their estrus cycle. And, unlike the chimp, bonobos “seemed to learn the symbolic use of words spontaneously, without requiring specific training in the different uses to which words can be put.” 44
Now let us compare traits that are unique to humans and (common) chimps, but not to orangutans, and traits that are unique to humans and orangutans, but not to chimps; there are only about 7 in the first category but about 40 in the second. (Grehan, 2006). This comparison was made in some detail by Dr. Jeffrey Schwartz, of the Department of Anthropology at the University of Pittsburgh (Schwartz, 1988; Grehan, 2006). Many of the traits unique to humans and orangutans are rather abstruse (e.g., extra holes in the base of the skull, rounded rather than bar-like brow ridges; Randall, 2005), but a few seem quite significant. For example, only humans and orangutans, of all the great apes (including even the gibbon), have a thick layer of enamel on the teeth, 45 just as Dryopithecus, Oreo, and Australopithecus did. The structure of teeth is highly conserved (it does not change much as a species evolves) 46 and, unless there is a reason why thick enamel would be selected for in humans and orangutans but not chimps, this suggests that humans are closer to orangutans than to chimps. 47
Like teeth, reproductive traits also do not change easily. In chimpanzees, the female genitals swell during ovulation (Fig. 23-14), signaling to males that she is ready to copulate, which does not occur in humans and orangutans (or gorillas Hrdy, 1987). Nipples in humans are farther apart than in African apes, and even farther apart in orangutans. (Schwartz, 2005, p. 154). Chimps, including bonobos, mate in a few seconds in public, front-to-back. 48 Orangutan sex is leisurely “with lots of touching with fingers and lips” (Randall, 2005), usually in private, and most frequently front-to-front. Like humans, female orangutans copulate when pregnant 49 and any time during the menstrual cycle; female chimps copulate only when in heat. Compared to chimps, the menstrual cycle is shorter in humans and orangutans, but the gestation period can be longer. (Table 23-1, Schwartz, 2005, pp. 154, 244).
|Primate ||Bonobo ||Chimp ||Gorilla ||Human ||Orangutan
|Menstrual cycle (days) ||47.7 ± 4.9 ||33.5 ± 3.9 ||30.0 ± 2.8 ||28.4 ± 1.8 ||27.3 ± 0.5
|Gestation period (days) ||- ||245 ||260 ||270 ||230 to 250|
[225 to 275] 50
Female orangutans play a greater role in choosing their mate than do female chimps. Male and female orangutans pair bond, mating with the same partner, though they separate in between matings and matings can be up to seven years apart. Orangutans live longer than the other great apes (40-50 yrs in the wild and 50-60 yrs in captivity) and have the strongest mother-infant bond. The age of weaning is 6.0 yrs for orangutans, 4.8 for chimpanzees, and only 2.8 for modern humans. (Hawkes, K., 1998). (“… orangutans have the latest age at first birth and are the ‘slowest’ [maturing] of the non-human great ape species.” (Robson, 2008).
Chimps have brow ridges, but humans and orangutans lack them. 51 Male humans and Sumatran orangutans have beards and moustaches; chimps don’t. 52 Orangutans and humans have long hair and, like orangutans (Figure 10-12), some humans have a receding hairline over the forehead (Figure 10-11); chimps don’t. 53 Next to humans, orangutans have the greatest amount of left-right asymmetry in their brains, which is related to the acquisition of language and handedness (orangutans are predominately right handed; chimps use either hand). 54 And, get this, only humans and orangutans smile with a closed mouth. 55 (Fig. 23-15). The caption reads, “Since the birth of her off-spring, Jessica has changed. Her previous depression has lifted, and she now smiles most of the time.”
Orangutans have culture (van Schaik, 2003), use human tools, copy human behavior, and have a mechanical ability that anticipates humans. They are the Houdinis of the primate world, able to escape cages by tinkering with their locks. 56 Unlike chimpanzees, orangutans construct shelters with roofs and sometimes even sides.
More evidence of a human-orangutan linkage comes from endogenous retroviruses. A retrovirus, such as HIV, uses RNA instead of DNA, plus an enzyme, reverse transcriptase. When the virus infects its host, the reverse transcriptase converts the virus RNA into DNA, which is inserted into the host’s own nuclear DNA. The host then makes more viruses from the virus’s DNA. If the DNA that came from the virus was inserted into a non-reproductive (“soma”) cell, it dies with the animal. But if it was inserted into DNA in an egg or sperm (“germline”), it can become a permanent part of all the progeny, an “endogenous” retrovirus. Over 8% of our genome consists of broken and disabled retroviruses.
At least two families of endogenous retroviruses, “PTERV1” (Yohn, 2005) and “CERV2” (Polavarapu, 2006) are found in the African primates (chimp, gorilla, baboon, and macaque), but are not found in humans, orangutans, and other Asian apes (siamang and gibbon). 57 Given that the infection occurred many millions of years ago, it is possible that humans and Asian apes were somehow immune to the virus, but a more plausible explanation is that humans and Asian apes share a common ancestor that is more recent than the common ancestor that humans share with African primates. Referring to Figure 23-12, the retrovirus entered the chimpanzee lineage (line C) after the C/H LCA, so it could not enter the orangutan-human lineage (line O-H). The absence of these endogenous retroviruses in humans and Asian apes is further evidence that the human lineage is from an Asian ape, not an African ape. 58
Table of Contents
1. “… man zoologically became man when he first walked erect …” (Howells, 1948, p. 102). Back
2. A recent genetic study shows that the colugo, which glides like a flying squirrel, is closer to primates. (Janeka, 2007). (Howells, 1958, pp. 65-66; Gebo, 2004). Back
3. (Smith, T., 2006). However, North America could also be the origin of Teilhardina; the oldest fossils have recently been found there. (Beard, 2008).
4. (Rossie, 2006). Fossil tarsiers have been found in Asia, Europe, and N. America but “no tarsiiforms have ever been found in Africa.” (Paleos: The Vertebrates). The tarsier is so primitive that it is the only mammal that has reptile-like scales around the nipples and on the tail. (Schwartz, 2005, p. 117). Back
5. Today’s heavier primates walk bipedally in trees, walking on top of branches while grasping other branches with their hands to provide additional support, thereby enabling them to reach fruit at the ends of small branches. (Thorpe, 2007). Back
6. In Table 9-2, note the position of the foramen magnum in the adult and young chimpanzee and gorilla. The embryonic positions of the foramen magnum, the vagina, and the big toe (Chap. 6) suggest that the earliest mammals lived in trees and had a vertical posture. It is possible that there was never a quadruped in man’s lineage. (Filler, 2007a & 2007b). In that case, the farther back position of the foramen magnum in some of today’s populations may be due to ancient interbreeding between the chimpanzee and human lineages.
7. Millions of years ago Europe was warmer and wetter and many species of ape lived there. "Found in Germany 20 years ago, this specimen is about 16.5 million years old, some 1.5 million years older than similar species from East Africa. It suggests that the great ape and human lineage first appeared in Eurasia and not Africa." (Heizmann, 2001). Back
8. For example, Dryopithecus brancoi was found in a swampy area of Hungary. (Kordos, 2000). Morotopithecus bishopi, an ape that lived in trees in Uganda 20 mya and walked upright on branches, may have also been in our lineage. (Gebo, 1997). Back
9. Fig. 23-4 is a reconstruction by John Gurche. (Gurche, J., “Flesh from Stone,” Scientific American, July, 2003). Back
10. When weapons are used instead of teeth, individuals without prominent canine teeth are at least as reproductively successful as those who have them. (Ardrey, 1966, pp. 262-263). Back
11. “… here is an ape [Dryopithecus] who lived throughout the Old World and was almost certainly the ancestor of the chimpanzee and probably of the gorilla and of man as well (and even of the orang …).” (Howells, 1948, p. 98). Back
12. “The zygomatic possesses [cheek bones] derived characters which reveal that Dryopithecus is related to the Ponginae [Asian apes] and not to the African apes/humans, as recently suggested.” (Sola, 1993). “Any one of the species in this genus may have been the ancestor to the modern orangutans.” (Wikipedia, “Sivapithecus”). Also (Schwartz, 2005, pp. 72-75, 138, 204). Back
13. “… Gregory calls him [Ramapithecus] almost human dentally.” (Howells, 1948, p. 99). Back
14. Oreo was first considered to be bipedal, then not bipedal (Coon, 1962, pp. 209-215), and is now believed to be bipedal again. (Rook, 1999). Another fossil bipedal ape, Orrorin tugenensis, dated at 6 mya, was found in Kenya. (Richmond, 2008). Back
15. (Kuliukas, 2002). The bamboo lemur, a primate, lives in bamboo forests in Madagascar and one species of lemur, the Bandro, “spends much of its time in water and can swim well.” (Wikipedia, “Bamboo Lemur”). This is the type of behavior that can select for the evolution of bipedalism. Consistent with man’s evolution from Oreo, the Swamp Ape, most early Homo sapiens sites are in coastal areas, suggesting that seafood was an important part of their diet. Seafood contains omega-3 fatty-acids, such as docosahexanoic acid (DHA) and arachidonic acid (AA), which are needed for brain health and intelligence. Back
16. Reconstruction by John Gurche. (Gurche, J., “Flesh from Stone,” Scientific American, July, 2003). Back
17. A number of Oreo fossils were found on an island in Kenya, dated at 15 to 16 mya. (Harrison, T., 1986). Back
18. If Oreo evolved in a croc-free northern environment, then the Oreo fossils found in Africa suggest that Oreo migrated into Africa from the north, and did not evolve there. Back
19. (Köhler, 1997). Even baboons walk bipedally when they cross water. Some believe (Wikipedia, “Aquatic Ape Hypothesis”) that during our evolution, we passed through a stage of living in water, citing evidence such as our ability to hold our breath. The traits they cite in support of that hypothesis tend to be neotenic. (Pratt, 2004; Purucker, 1977). Back
20. “Lucy” found in Ethiopia, was an Australopithecus afarensis. Back
21. Note that this is the skull of an African Australopithecus. A Eurasian Australopithecus may look even more like Oreo, but so far none have been found. Back
22. The painting is of Australopithecus boisei. Back
23. On the basis of bone and muscle similarities, humans and gorillas were found to be the most closely related of living hominoids. (Schwartz, 2005, pp. 208, 212). This suggests that man evolved from a robust type of Australopithecus, not a gracile type. Humans may be more closely related to A. anamensis, a robust Australopithecus, than to other species of Australopithecus. (Coppens, 2004, pp. 44-47). On the other hand, robust species tend to be primarily plant eaters (e.g., the gorilla), while gracile species eat more meat. Since man is gracile and eats more meat than other primates, one might suppose that he descended from a gracile Australopithecus, e.g., A. afarensis. Back
24. The absence of evidence is not evidence of its absence. (Carl Sagan). They did not, as did the Neanderthals, conveniently bury their dead so that paleoanthropologists, millions of years later, could find their bones. And, without fire, they were incapable of ousting bears and other critters from caves, as the Neanderthals did, so that their bones would be protected and preserved for us to find. Indeed, they were very likely cannibals, as were later hominids, as the smashed bones of their fossils showed they ate the marrow of their dead and, no doubt, the rest of them as well. The Chinese, foolishly believing that “dragon teeth” were an aphrodisiac, ground them up and consumed the powder, thus forever depriving mankind of knowledge of its past. Back
25. The oldest Australopithecus fossils have been found in NE Africa, which suggests that they may have come from SW Asia. (Coon, 1962, p. 304). Gaps in the African fossil record and the sudden appearance in Africa of new hominoid species are more consistent with migration into Africa, rather than to an African genesis. For example, “[The Australopithecines in Africa] are the only primate family lacking a known, proven ancestor who lived before the Pleistocene.” (Coon, 1962, p. 217). Back
26. Picture from Origine et évolution de l’Homme on the internet. Back
27. If man evolved from a Eurasian ape similar to Oreo, who presumably became bipedal by wading in water, orangutans who, unlike chimps, love water, are more likely to be on that branch than chimps, who fear it. (Kaplan, 2000; Russon, 2004). Back
28. There are also specializations for bipedal walking. “…the orang-utan is the only ape with a knee joint similar to that of humans. Orang-utans walk by extending their legs and hips to give a straight posture, whereas chimps waddle on two legs with bent knees and torso bent at the hip.” (Hooper, R., New Scientist, "Walking on two legs evolved surprisingly early," June 9, 2007, pp. 18-19; Thorpe, 2007). Back
29. (Richmond, 2001, p. 87; Schwartz, 2005, pp. 82-83). Two species of Australopithecus have a change in the radius [forearm bone] that suggests a knuckle-walking ancestor, but this could have been acquired by interbreeding and they lack other knuckle-walking adaptations. (Richmond, 2001). Also see (Raffaele, 2006). There is some evidence that early Australopithecus in Africa had adaptations for knuckle-walking, which may indicate cross-breeding with an African knuckle-walker. (Collard, 2000). Back
30. Another possibility is that a quadrupedal African ape interbred with a bipedal Eurasian ape that had migrated into Africa; the resulting hybrid population would have had both some quadrupedal adaptations and some bipedal adaptations and knuckle-walking may have been the best posture for the mixture. (Figure IV-1). The long arms of a brachiator and extending the wrists during knuckle-walking shift some weight to the legs and relieve the arms which, compared to the legs; the arms have better tensile strength, but the legs have better compressive strength. In the jungle, where the African apes live, bipedalism would be less useful than on the open savanna. Back
31. However, descriptions of bipedal apes can be found in Asian writings. (Coon, 1962, pp. 207-208). Back
32. The genetic distances from humans to bonobo chimp = 0.017 (1.7%), common chimp = 0.016 (1.6%), gorilla = 0.019 (1.9%), and orangutan = 0.031 (3.1%). (John Steer, Genetic Distances Among Primates, Evolution Evidence Page). The “sequence identity” between chimpanzees and humans decreases from 98.6% to 86.7% when insertions/deletions are included; the percent decrease has not been determined for orangutans. (Anzai, 2003). It has been estimated that humans have acquired 689 new gene duplicates (i.e., the gene is duplicated) and lost 86 since our LCA with chimps and gorillas 6 mya, while chimps have lost 729 gene copies that we still have (Demuth, 2006), and the differences may be greater between us and orangutans. There are a number of cases, however, where human DNA is closer to orangutans than to chimps, such as the “LINE1” sequence and Alu copies. (Patterson, 1999, p. 76). Back
33. The C/H LCA may have been between prosimians that had a horizontal posture (the chimp lineage) and those that had a vertical posture (the human lineage); interbreeding between the chimp and human lineages would make the LCA date more recent. Back
34. Also, orangutans have evolved away from the human lineage and Schwartz (2005, pp. 93-94, 188) argues that line O is long. Back
(Patterson, 2006; Arnold, 2006). Chimp-human interbreeding occurred for millions of years, finally ending 4.1 ± 0.4 mya. (Hobolth, 2007). Back
36. The chimp-gorilla split is dated at 8.4 to 6.2 mya (Chen, 2001) and bipedal apes, such as Sahelanthropus tchadensis (“Toumai”) were living in Africa at least 7 mya. “Her [the Dikika baby, an Australopithecus] two complete shoulder blades, the first ever found from an australopith, were similar to those of a young gorilla —” ("Childhood Origins," National Geographic, Nov., 2006). Back
37. Although there may have been DNA transfer from a chimp ancestor to a Homo ancestor (male chimps have been sexually attracted to women), it would have been confined to the African Homo lineage as chimps are African apes. At least one rape of a woman by a chimp has been reported. (Galdikas, 1995). Also see (Wikipedia, “Humanzee”). Back
38. (New Scientist, June 9-15, 2007, p. 18). Back
39. “No known fossil ape related to the orangutan is adapted for life in the trees, leading researchers to believe orangutans descended from a ground-dweller.” (Lovgren, 2004; Chaimanee, 2004). On the other hand, the orangutan’s feet (Fig. 4-1, p. 17) are not well adapted for walking. (Howells, 1948, p. 61). Back
40. Note the external genitalia, which are similar to those of the Hottentot women (p. 224). “Physically, their [bonobo] anatomy most closely resembles Australopithecus, our early human ancestor.” www.bonobo.org The ear size of the bonobo is smaller than the chimps’. (Coon, 1962, p. 146; also Zihlman, 1978). The foramen magnum is nearer to the front than it is in the common chimp. (Luboga, 1990) The many differences between chimp and bonobo suggest a genetic contribution to the bonobos from a more neotenic lineage and, of the major races, Asians are the most neotenic, followed by Caucasians, but Bushmen and Negritoes are also neotenic. (Figure 26-7). The common chimp and the bonobo were separated about 1.3 mya by the Congo River. Back
41. Bonobos live in the swampy rain forest basin of the Zaire River. (De Waals, 1997, p. 12), “They [bonobos] tend to like swampy areas, where sometimes they dig for grubs or small crustaceons [sic].” (Bonobo Initiative). Another possibility is that interbreeding with, say, Oreo, occurred before the chimp/bonobo split and that the bonobo and chimp populations were selected from the resulting diverse hybrid population. Back
42. Also, its curial, brachial, and humerofemoral indices are closer to humans than are the common chimps’. (Aiello, 1990). Back
43. The foramen magnum is farther to the front in the bonobo than it is in the chimp, but is still farther forward in the orangutan, though less horizontal. (Luboga, 1990). The bonobo is closer to humans in form and behavior. (Coppens, 2004, p. 13; Patterson, 1999, p. 82).
44. (Raffaele, “Speaking Bonobo,” Smithsonian.com.; Corballis, 1991, pp. 150, 1001). Bonobos are also less sexually dimorphic than common chimps. (Luboga, 1990). Back
45. (Schwartz, 2005, p. 68, 204; Schwartz, 2000). So similar are orangutan teeth to human teeth that many fossil teeth initially identified as hominids, such as erectus, turned out to be orangutan teeth. Also, when the hoax of the Piltdown Man was concocted, an orangutan jaw was used because it is so similar to a human’s. (Schwartz, 2005, pp 35-37, 66-67, 72, 138). Back
46. “Our dental pattern emerged at least 60 million years ago.” (Schwartz, 2005, p. 116). Back
47. Wrinkled teeth appear in Mongoloids, especially ancient Mongoloids, orangutans, and Australopithecines. (Coon, 1962, p. 357; Schwartz, 2005, p. 94). Back
48. (Kaplan, 2000). Bonobos use front-to-front more than common chimps, but front-to-back is still twice as common. (De Waal, 1997, p. 102). The front-to-front sexual encounters of bonobos are believed to be mostly homosexual. (Schwartz, 2005, p. 14). Back
49. During pregnancy, both orangutans and humans excrete 4 or 5 times more estriol than the African apes; estriol may spur fetal brain growth. (Randall, 2005). Back
50. This broader range is from the Center for the Great Apes.
51. (Howells, 1948, p. 66). “The head of the infant ourang outang is like that of a well formed Caucasian child in the projection and height of the forehead and the convexity of the vertea [the crown of the head].” (Cartwright, 1857, p. 45). Back
52. (Moyà-Solà, 1999). Back
53. (Schultz, 1936). And, of course, there is that intriguing red hair that they share with the Irish. Back
54. (Brésard, 1983; Schwartz, 2005, pp. 132, 156-157). But also see Hopkins (2003). Back
55. (Kaplan, 2000), courtesy of the author. Back
56. (Russon, 2004). “[O]ne wild orangutan laboriously dismantled his cage when a screwdriver was accidentally left within reach.” Another “stole a small boat, paddled across a stream, held onto the rope while he foraged, and then paddled back again …” A female orang even learned “a complex, multi-step procedure” for lighting fires. (Randall, 2005). “Unlike chimpanzees, who will physically attempt over and over again to solve a problem, orangutans commonly think through the solution to a problem.” (Schwartz, 2005, p. 11). Another indication that orangutans have a more advanced brain: “[There are] anecdotal reports that orang-utans can monitor their own actions – for example, Rob Shumaker from the Great Ape Trust of Iowa in Des Moines says that orangutans will sometimes refuse to continue doing a selection task if they think they have made a wrong choice, holding out until they are allowed to try again.” (“Known Unknowns,” New Scientist, Dec. 16-22, 2006, p. 31). When orangutans at the Max Planck Institute for Evolutionary Anthropology saw a peanut floating in a plastic tube, they got it out by spitting water into the tube until the peanut came to the top. (Mendes, 2007). Orangutans are a bit more intelligent than chimpanzees (Deaner, 2006) though very slightly less in brain size (397cc vs. 400cc). Back
57. That is also true of the type C viral gene. (Benveniste, 1976). Back
58. Since the chimp and human lineages interbred, the absence of these retroviruses in humans would require the breeding to be between males in the human lineage and females in the chimp lineage, certainly more likely than the reverse. “No African fossil has ever been found that is related to chimpanzees or gorillas.” (Lovgren, 2004). “… there are no fossil ancestors assigned to the African apes for something on the order of 14 million years of geological time …” (Kleindienst, 1975). The absence of fossils of their ancestors in Africa may suggest that their ancestors did not originate in Africa, which would mean that man did not descend from an African ape, even if his ancestor with the chimpanzee is more recent than his ancestor with the orangutan. Back