Chimpanzee hand structure6/7/2023 Both ourselves and chimpanzees almost certainly have our complex carpal bones to thank for part of our developments in tool usage, since they allow the freedom of movement needed to carry out complex and dexterous tasks.Ĭanon Alberic’s Preserved Chimpanzee Hand While chimpanzees do climb, they tend to be terrestrial and express a mixture of bipedal stances, often ‘knuckle-walking’ by walking on all fours with their wrists extended. Both of us have smoothed and highly grooved carpals, allowing extensive rotation and flexing, an essential condition needed for arboreal climbers. Naturally the chimpanzee wrist shares a great deal of similarity with the human wrist, owing to our intimately close ancestry. The chimpanzee wrist is comprised of eight carpal bones, having lost the prepollex and centrale, the remaining majority of primates tend to have the full set of ten. Whereas carpals generally appear more curved and smooth in the case of species that require a large amount of dextrous movement, like gibbons and other arboreal (tree-living) primates, who tend to enjoy doing a good swingy-swingy. A fossorial (burrowing) animal, such as a mole, that spends most of its free time digging about in the soil tends to have a tougher and squarer set of carpal bones, thus helping resist pressures caused by the strong earthen substrate. Image from Lewis (1989).Īlthough relatively unstudied until recent years, the shape of carpal bones tend to provide a wealth of information relating to the ecology of the species in question, since the forearms tend to do a lot of the work an animal undertakes during its day-to-day routine. The standard mammalian wrist, including labelled carpal bones. Those comprising the bottom row are the Scaphoid (S), Lunate (L), Triquetral (or Cuneiform, Cu) and Pisiform (Pi) along the top are the Trapezium (Tm), Trapezoid (Td), Capitate (C) and Hamate (H) often there are an extra two bones thrown in as a bonus: a tiny bone below the thumb called the Prepollex (pp), and an intermediary bone in the centre of the wrist called the Centrale (c). The mammalian wrist is formed of a series of globular, tessellating bones called the carpals, forming two rows. This solitary manus will do enough, for what lies within is extra special…Ī Whistle-stop Tour of the Mammalian Wristīridging the gap between the long bones of the forearm and the proceeding bones of the digits there is a fertile land of great mystery and intrigue, otherwise recognised as the wrist. But it is not the remaining post-hand specimen that I am interested in today. They are highly intelligent, even for primates, and form societies with highly complex structures, building language, traditions and not to mention tools. I understand that by re-working Eric Idle’s Eric the Half a Bee song to read ‘chimpanzee’ instead of ‘bee’ most of the rhyming joke is lost, but I digress.Ĭhimpanzees, Pan troglodytes , along with bonobos, are our closest living relatives. LDUCZ-Z1146.Īt the Grant Museum of Zoology we house enough material to comprise at least half a chimpanzee, probably even several halves… Many different pieces of evidence feed into such arguments, and scientists go with the conclusion most consistent with the evidence.Preserved chimpanzee manus (hand). This ensures that scientists’ reasoning is not circular. Sometimes a phylogeny is used to help determine if a trait is or is not homologous however, this phylogeny is based on other traits, not the trait in question. Scientists don’t always start with anatomy in determining if two structures are homologous. This (along with tons of other evidence) suggests that humans, chimpanzees, and gorillas are more closely related to one another than any of them are to pandas. The panda’s thumb, however, evolved independently from these primate thumbs. For example, humans, chimpanzees, and gorillas all have thumbs that are very similar anatomically and are homologous. Only homologous traits are evidence of shared ancestry and can be used to reconstruct the evolutionary relationships between different species.
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