The intermembral index is a ratio used to compare limb proportions, expressed as a percentage. It is equal to the length of forelimbs (humerus plus radius) divided by the length of the hind limbs (femur plus tibia) multiplied by 100, otherwise written mathematically as: (+) (+) ×The intermembral index is used frequently in primatology, since it helps predict primate locomotor patterns.
Other articles where Intermembral index is discussed: primate: Four types of locomotion: …being strictly quantitative, is the intermembral index. Briefly, the index is a ratio expressed as percentage of arm length to leg length; an index over 100 indicates relatively long arms. This provides a model by means of which the locomotion of an early primate can be inferred by determination of…
Intermembral Index =82 semi-terrestrial and semi-arboreal omnivourous long legs + long arms=quadrupedal walking Indri Lemur Intermembral Index=65.2 powerful legs 1/3rd longer than arms arboreal Intermembral index = 84 Branchite omnivorous Weeping Capuchin Vervet Monkey Siamang
When the subject of primate arboreal locomotion is studied in evolutionary terms by using fossils, it becomes clear that locomotor categories are not discrete but constitute a continuum of change from a hind limb-dominated gait to a forelimb-dominated one. The best single indicator of gait, one that has the added advantage of being strictly quantitative, is the intermembral index.
The intermembral index is a useful tool in understanding the locomotor activities of a given primate. The indices are determined by the humerus, radius, femur and tibia. A low index indicates a primate with longer hind limbs, more prone to bipedal activities, while a high index signifies longer fore arms and thus more prone to quadrupedal activities.
The humeroradial index (94.6%) is only slightly less than that of the lion (98.3%) and the cheetah (103.3%), while the femorotibial index (105%) matches that of the cheetah, indicating longer lower limbs for a longer stride and potentially higher running speeds. The intermembral index is only 84.7% and falls within values for other large cats ...
The intermembral index for a chimpanzee is 106 to the 12th degree whereas the intermembral index for a human is 88 to the 11th degree. The intermembral index is a ratio of limb proportions that provides insight into the type of locomotion of an animal.
- intermembral index of 70 - used by: prosimians. Arboreal Quadrupedalism ... - many old world monkeys, a few new world monkeys, chimps, bonobos - low sexual dimorphism. all male groups ... Anthropology 2200 OSU Exam 2 40 terms. mlisbon728. Primates 39 terms. dimitri_alexander6.
primate locomotion. Primates are an arboreal radiation. However, there is a great deal of variation in their locomotion patterns. Five categories of primate locomotion are typically recognized : -arboreal quadrapedalism - terrestrial quadrupedalism - vertical clinging and leaping - suspensory - bipedalism ... intermembral index= measure of the ...
Distribution: The colobus monkey is widely distributed throughout Africa including Senegal, Ethiopia, Angola, Zaire, Tazania and Malawi (Napier and Napier 1985). Tail: Yes. Mode of locomotion: These monkeys are arboreal quadrapeds, and have an intermembral index of 79. On occasion they may semi-brachiate through the trees, which is not seen in the cercopithecine family.