Comparison of Primate Locomotion

Ring Tailed Lemur

Lemurs (Prosimians/Strepsirhini)

Environment:  Lemurs are found exclusively in Madagascar, Madagascar has a coastal plain, high plateau and mountains.  The climate is tropical along the coast, temperate inland and arid in the south. The gallery forests that Ring-tailed lemurs prefer are rapidly being converted to farmland, overgrazed by livestock, and harvested for charcoal production.

Locomotion:

Lemurs are quadrupedal, meaning that they use all four limbs for locomotion.  Ring-tailed lemurs are more terrestrial, but also arboreal.  Sifaka lemurs are more arboreal and use vertical clinging and leaping.  They support themselves vertically by grasping onto tree trunks or other large plants with their knees and ankles tightly flexed.  They can spring away in a forwards or backwards motion by forcefully extending their long hind limbs. (Jurmain p 151)  Dwarf lemurs use a slow and cautious climbing form of quadrupedalism.  Their flexible hip joints permit suspension by hind limbs while using the hands in feeding.  Lemurs cannot use their tails for grasping.  (National Geographic - http://animals.nationalgeographic.com/animals/mammals/ring-tailed-lemur/)

How locomotion has been influenced by its environment:

The more than 60 lemur species have been influenced by its varied environment by both mainly arboreal and mainly terrestrial species being found in the differing climates of Madagascar.  Sifakas and indris are found more in the tropical and dry forests of the country and have a diet of leaves, fruit, bark and flowers.  They have developed their locomotion so much to an arboreal environment that on the ground their only locomotion is hopping.  Ring-tailed lemurs have a more varied omnivorous diet mostly of leaves, fruit, buds, bark and shoots but also of insects and small birds and chameleons.  They are the most adaptive of the lemur species spending equal amounts of time on both the ground and in trees.  Troop travel time is terrestrial.  The dwarf lemur, which is nocturnal and insectivorous, spends nearly all of its time in an arboreal existence.  So, within the 3 examples of the lemur species, we can see that the environment, habitat and diet of all 3 directly relate to their locomotion.

Sifaka

 

Dwarf Lemur

Spider Monkey (New World Monkey/Platyrrhini)

Environment:

Spider monkeys live in evergreen rainforests, semi deciduous and mangrove forests in Central and South America and as far north as Mexico.  They almost never come down to the ground.  Living mostly in the upper canopy, they prefer the undisturbed areas of the high forest. 

Locomotion:

While Spider Monkeys use a method of locomotion called semi-brachiation, a combination of leaping with some arm swinging, (Jurmain p 151) they are also quadrupedal, using all four limbs when walking or running.  When feeding they do so with brachiation, suspending themselves while eating rather than picking their food and moving it to an alternate location.  They also use their tails as additional support through the trees.  (National Geographic  http://animals.nationalgeographic.com/animals/mammals/spider-monkey/)

Spider Monkey

 How locomotion has been influenced by its environment:

The brachiation of the Spider Monkey is influenced by its environment as they spend almost all of their time in the upper canopy of high forests.  With a diet of fruits and seeds, leaves and aerial roots, it would be necessary to have for the Spider Monkey to have strong brachiation skills in order to maneuver quickly through the tree tops and obtain its food at the same time.  The adaptation of the use of the tails is also a feature adding to their agility.

 

Baboon

Baboon (Old World Monkey/Cercopithecidae)

Environment:

Baboons live in Africa or Asia preferring savanna and other semi-arid habitats.  A few baboons live in tropical forests. 

Locomotion:

Baboons move about quadrupedaly almost exclusively on the ground.  Unlike, New World Monkeys, Baboons do not have prehensile (gripping) tails.  While they do climb trees to avoid predators, seek food or sleep, they spend most of their time terrestrially.   (National Geographic Magazine - http://animals.nationalgeographic.com/animals/mammals/baboon/)

How locomotion has been influenced by its environment:

Living in the savannah regions of Africa and Asia, there is not a need for many tree climbing skills.  Baboons are opportunistic eaters foraging for most of their fruits, grasses, seeds, barks and roots.  But, they can also eat birds, rodents and the young of other small mammals.  Due to the diminished need for tree climbing, the baboon has adapted to its savannah environment by moving about more efficiently on the ground.  They also have developed rough spots on their protruding buttocks, called ischial callosities, which enables them to sit on the hard savannah ground for longer periods of time.

 

Gibbon

Gibbon (Lesser ape/Hylobatidae)

Environment:

Gibbons are tree dwellers living in the dense forests of Southern Asia. 

Locomotion:

Gibbons use brachiation as their primary method of locomotion.  If they do come down to the ground, they walk bipedaly using their arms high above their heads in a swinging motion for balance.  Gibbons are so good at brachiating that they can reach speeds of up to 35 mph and distances of 50 feet with one throw of their bodies from one tree limb to another.  

 (National Geographic http://animals.nationalgeographic.com/animals/mammals/gibbon/)

How locomotion has been influenced by its environment:

Gibbons spend most of their time in an arboreal environment, thriving on the abundant fruit trees in their tropical range.  Their food supply has aided them in developing the added agility and skill for maneuvering through the tree tops.  Their arms are quite a deal longer than their legs and their hands have also specially adapted to having better grip in the trees.  Gibbons do not have tails for balance, so their oversized arms are the main source of their locomotion.

Chimpanzee

 Chimpanzee (Great ape/Hominidae)

Environment:

Chimpanzees can be found in African rainforests, woodlands and grasslands.

Locomotion:

Chimpanzees normally walk on all fours, called “knuckle-walking”, however chimpanzees can stand and walk upright demonstrating bipedal locomotion. By swinging from branch to branch using brachiation, they can also move quite efficiently in the trees.  It is thought that Chimpanzees were once more of tree dwellers and therefore have retained the elongated arms for brachiating. 

(National Geographic - http://animals.nationalgeographic.com/animals/mammals/chimpanzee/)

How locomotion has been influenced by its environment:

Chimpanzees spend much of their time on the ground, however they sleep and eat in the trees and even make nests of leaves to sleep in. They are mainly fruit and plant eaters, but can also eat insects, eggs, and meat, including carrion. They have a varied diet which includes hundreds of foods.  Due to their varied environment, chimpanzees have adapted to be able to spend much of their time on the ground and in the trees with an equal amount of ease.  Chimpanzees also have a padded bottom enabling them to sit comfortably on the hard ground for longer periods of time.

Summary:

The following chart illustrates the various traits predominantly exhibited by each species. In the beginning while all 5 primates compared are quadrupeds and vertical climbers to some degree, being able to walk on the ground as well as climb trees (Jermain p 150), their natural environments have a great influence on their specializations.  The more arboreal the environment of the primate, the more brachiating is used as the main mode of locomotion and perhaps the use of a prehensile tail.  The more terrestrial the primate, the more quadrupedal and the addition of knuckle walking is observed.   In terrestrial primates, the arms are in more direct proportion to the length of the legs.  In more arboreal primates, the arms are more elongated due to brachiating as the main mode of locomotion.   As evidenced in the different body types and abilities of the 5 primates, the environment and habitat can play an important role in the evolution and adaptation of each species over time.   

Notable for the lemur species, which has over 60 species in Madagascar, is that it has maintained its equal limbs ratio although the sifaka spends most of its time in the trees as well as the dwarf lemur.  However, the sifaka does not brachiate, but rather leaps through the trees using its hing legs and arms to catch itself, and the dwarf lemur has maintained its very small proportions.  Ring-tailed lemurs, which  spend equal amounts of time on the ground and in the trees have equal arm and leg length.  As lemurs have adapted to their various environments undisturbed of other primate species, it is interesting to see how the lemur species alone has so many variations. 

	Environment		Locomotion						Distinctions
Primate	Arboreal	Terrestrial	Quadrupedal	Vertical Climbing	Leaping	Semi-Brachiation	Brachiation	Knuckle Walking	Elongated Arms	Equal Limbs
Lemur	X	X	X	X	X					X
Spider Monkey	X		X	X	X	X			X
Baboon		X	X	X						X
Gibbon	X		X	X	X		X		X
Chimpanzee		X	X	X				X		X