Why Can’t Chimpanzee Walk On Two Legs ?
Chimpanzee (Pan troglodytes) is a species of the great ape native to the Savannahs and forest of tropical Africa. They are human’s closest relative and has a DNA similar to that of humans.
In this post, however, I’ll be throwing this under the microscope, and will be shedding more light on the reasons why chimpanzee can’t walk comfortably upright as humans do.
The inability of chimpanzee to walk on two feet for long is owing to the physical features and attributes listed below:
- Their spine unlike humans’ is connected to the skull at the back, holding the head at an angle rather than firmly upright as seen in humans.
- The length between the upper thigh and the hip bone in chimpanzee are shorter, thereby, allowing little effective contraction of the hip muscles for upright walking.
- Chimpanzee’s knee joint is not as strong as humans’, and makes it hard for chimps to rest their weight on one leg at a time to walk for long periods.
- Chimpanzee arms are longer than their legs as opposed to humans, who has both arms relatively shorter when compared to their legs.
- The big toes of chimps are opposable and are effective in grasping, which further enhances their arboreal locomotion.
- The pelvis in chimpanzee are long with an extended flat ilium.
- Chimpanzee’s vertebral column unlike humans is bow-shaped, making it unable to support the weight on their upper torso.
- Chimpanzee legs point outwardly from the hips, while humans’ point slightly inwardly, for ease and convenience in walking.
- Chimps femur unlike humans are angled out.
Though the above listed features in chimpanzee makes walking bipedally for long impossible, these physical features are however, best suited for knuckle-walking,
a form of quadrupedal walking in which the forelimbs hold the fingers in a partially flexed posture that allows body weight to press down on the ground through the knuckles as seen in gorillas.
This form of locomotion allows the chimp to carry the weight on all fours rather than on two limbs, and is adapted for their easy arboreal and terrestrial locomotion.
This type of walking according to recent studies has been claimed to be more energy costing than humans’ upright bipedal walking.
Chimps are also reported to have a greater physical strength when compared to humans.
Contents
What Is The Ability To WALK ON Two Legs ?
Bipedalism is the ability of an organism to walk or move on its rear limbs or two legs, as seen in humans, Ostriches, pangolins, kangaroo rat and mice, some lizards, and several primate species as Indriids and Gibbons.
The term Bipedalism is formed from the Latin words ‘bi(s)’ which means “two”, and ‘ped’ which translates as “foot”.
The major types of bipedal movement are as follows:
- Walking
- Running
- Hopping
BIPEDALISM IN ANIMALS
Animals with this form of locomotion are few when compared to other terrestrial quadrupled vertebrates.
And are majorly amphibians, extant reptiles and lizards, archosaurs (comprising of Birds, Dinosaurs, and Crocodiles), mammals like giant Pangolins, giant ground Sloths and macropods, and other jumping rodents.
And in other primates like the Bonobos, Chimpanzees, Gorillas, Baboons, Gibbons, Indriids, and Sifakas.
BIPEDALISM IN HUMANS
Bipedalism in humans can be traced back to one of the earliest hominids known as Sahelanthropus, who may have walked on two legs seven million years ago.
And the trend was recorded to have continued evolving from the time of hominids like Australopithecus Africanus to the time of the Homo Erectus about 1.9 million years ago, up to the age of modern humans.
The reasons for human bipedal evolution has been cited to have involved freeing the hands for carrying tools, babies, and foods;
allowing the greater field of vision needed for easy detention of possible threats and dangers, climates changes,
efficiency in navigating open landscapes, and covering long distances, less energy cost for walking on two legs, convenience in hunting, appearing larger and more intimidating among others.
Disadvantages of Walking Upright
- Back pain and other skeletal problems are common side effects of walking upright.
- Distributing the weight of their bodies on just two limbs are causal factors of arthritis in humans.
- Lower back pain is also as a consequence of upright walking in humans.
- Collapsed foot arches are also a major side effect of bipedal walking.
- Humans sometimes suffer slipped disks as a result of bipedal walking.
- It makes our ability to climb trees less efficient when compared to those recorded in early humans.
- Bipedal primates like humans tend to be slower than other vertebrate quadruples.
- Bipedal walking is unbalanced when compared to animals with more than two legs.
- Losing a leg may affect the mobility of an upright-walking Mammals.
- Too much strain on joints and knees may damage the joints or knees.
The similarities between humans and this species of great ape extended to physical areas like; their long-fingered hands, round head and prognathous,
hairless face, forward-facing eyes, rounded non-lobed ears, small nose, long mobile upper lip and, in their adult males, sharp canine teeth.
Likewise, they exhibit intelligence and cognitive processes like weapon making, tool use, cooperation, mourning, crying, self-awareness among others.
And also has an eight months’ gestation period, closer to that of humans. And like other primates weaned their infants for about two to three years.
While possessing all these aforementioned human attributes, chimp as they are colloquially known differs with humans in such aspect as higher intelligence and cognizance level and that they mostly move quadrupedally and may occasionally walk bipedally.
