Monkeys may have developed an upright body structure to more easily pick leaves rather than fruit. Reported by the University of Michigan.
For a long time, the opinion prevailed among anthropologists that the ancient apes and human ancestors acquired a vertical orientation of the body and moved to a partial upright posture for more convenient fruit extraction. Basically, the fruits grow away from the trunk and thick branches. Therefore, to pick it up, the monkey must lean on the branches and stretch his hands towards the prey; this is much more convenient when the body is placed vertically – this is especially true for great apes, such as chimpanzees, who can only stand. thickest branches.
Laura McLatchy and colleagues afflicted The study suggested that this adaptation may have evolved to feed on leaves rather than fruits. The study’s authors analyzed the 21-million-year-old fossilized remains of Morotopithecus. In the same layer, preserved traces of ancient soil and plant traces were found, as well as the remains of other mammals. Thanks to all this, scientists were able to reconstruct the habitats of ancient apes.
It turned out that the studied plants experience the so-called “water stress”, that is, they experience periods of rain and drought. It also means that for at least part of the year, monkeys have to rely on something other than fruit for survival. Together, these finds indicate that Morotopithecus lived in an open forest with abundant clearings and shrubbery.
The first sign that these ancient monkeys ate leaves was in their molars. They were very “rough” with many hills and valleys. This structure is necessary for tearing the fibrous leaves, while the molars used for eating fruit are usually more rounded.
The researchers also examined the tooth enamel of monkeys and other mammals in the same stratigraphic layer. They found that the isotope ratio in tooth enamel indicates that great apes and other mammals eat C3-type plants. C3 plants are mostly woody shrubs and trees, while C4 plants are plants adapted to dry conditions.