That’s Incredible: Trapeze Artist
A major evolutionary trend that separated early primates from other early mammals was arboreal living. While most mammals chose to move to grassland, marine and other ecosystems, primates made trees their niche.
Photograph by Sandeep Das.
Though this arboreal hypothesis has been challenged by some scientists who say that visual predation – adapting to lower tiers of the forest canopy and bushes to feed on insects – was a precursor to living on trees, primates eventually showed a marked preference for their elevated abodes and became masters of the arboreal environment. Early primates quickly developed binocular vision (the ability to focus both eyes on an object) and stereoscopic vision (the ability to gauge an object’s depth – a feature essential for arboreal life), grasping prehensile hands and feet with opposable thumbs, and big toes with wide nails instead of claws. They also adopted an omnivorous diet and elaborate social systems to cope with their new lifestyle. Most importantly, they developed a whole range of locomotive adaptations – some became fast movers on the ground, some scaled vertical trunks and branches with ease, while others learnt to swing effortlessly from one branch to another.
Descendants of these primates have now perfected these adaptations, exhibiting unrivalled acrobatic skills as they jump from branch to branch. Apes, for example, exhibit brachiation – suspending themselves from branches and moving across by swinging their arms. This helps conserve energy by treating the body as a swinging pendulum to gain momentum for forward movement. Others, such as lemurs, have relatively longer legs than arms and hence prefer vertical clinging and leaping.
Quadrupedal monkeys, such as lion-tailed macaques, have limited arm movement and instead prefer to use all four limbs to move. This kind of movement, called quadrumanous locomotion, indicates a preference for moving on land or in trees using one limb at a time. More rarely, quadrupedal monkeys may choose to leap, to bridge a large gap between trees, as this lion-tailed macaque photographed in the Sholayar forests in south India chose to do.
Location: Sholayar, February 3, 2013
Camera: Nikon D7000; Lens: 300 mm.;
Shutter speed: 1/1000 sec.; ISO: 200;
Aperture: f/4.5, no flash.
Author: Sanctuary Asia, First appeared in: Sanctuary Asia, Vol. XXXIII, No. 2, April 2013.