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Recently, 18 elephants died on a hilltop in Assam. The preliminary post-mortem report indicates they had been struck by lightning.
Process of formation of lightning
- During a storm or rain, particles of rain, ice, or snow inside storm clouds collide with each other. It creates a negative charge in the lower reaches of storm clouds and a positive charge in the upper reaches of clouds. This imbalance results in inter-cloud lightning.
- Ground Objects like trees and earth itself during storms become positively charged due to friction with particles. It creates an imbalance between earth and cloud. Thus, nature seeks to balance this by passing current between the two charges i.e. from clouds to earth.
- Thus, lightning is the process of occurrence of a natural electrical discharge of very short duration and high voltage between a cloud and the ground or within a cloud. It is accompanied by a bright flash and sound and sometimes thunderstorms.
- Inter cloud or intra cloud(IC) lightning are visible and are harmless.
- It is cloud to ground (CG) lightning that is harmful as the ‘high electric voltage and electric current’ leads to electrocution.
How does lightning kill animals? Lightning may injure or kill animals in a number of ways such as:
- Direct Flash: An animal in an open field may be struck directly by lightning if part of its body covers or is over other objects in the vicinity. Taller animals are more vulnerable.
- Side Flash: When lightning strikes a tall object such as a tree, it may generate a side flash that can strike an animal standing underneath the tree.
- Touch Potential: If one part of a tall animal’s body is in contact with the ground, while another part touches a lightning-struck object like a tree, a partial current may pass through its body.
- Step Potential: It is the most common lightning hazard among four-legged animals. When an animal’s front and hind feet are far enough apart, a partial current may pass through the body in certain circumstances.
As per the investigation team, it may be the step potential that killed the Elephants.
Why are elephants more vulnerable to lightning?
- An elephant’s front and hind feet are wide apart. Therefore, it would appear to make it more vulnerable than a smaller animal, such as a rat.
- This is because the potential difference increases with the increasing distance between the two feet. The larger the potential difference, the greater the current through the body.
Source: Indian Express