Lion and tigers can eat animals by using their paws and teeth.  Snakes do the same by injecting venom and swallowing predators. 

Snakes, however, have one more important role: they manage the food chain for all the animals on the earth! They eat predators like rodents ( example-rat) who are massive food-eaters. Rodents also multiply in large numbers. They are a threat to the vegetarian world. 

They also hunt and eat frogs that are predators to small fish. 

Snakes often get bad names, but they are more central to ecology than most people realize. They even mitigate climate change by spreading the seeds that go in their digestive track when they eat rodents. Those are thrown away as excreta from snakes as full seeds because snakes are fully carnivorous! 

Snake venom is processed and used for cancer treatment. Cancer is one of the leading causes of morbidity and mortality worldwide. The animal we despite and kill or run away at first site is manager of our food supply and health. What more if you are bitten by snake the anti-venom produced by using its venom can help cure the patients and processed diluted venom are given to horses as a precaution against snake bites. 

Thus we have five reasons why we call a snake an ecosystem Manager. 

• 1. It manages food-grains by eating rodents.
• 2. It manages protein supply by eating frogs that eat small fish- a source of proteins to many
• 3. It mitigates climate change by growing forests with seeds that it disperses. 
• 4. It is used to make anti-cancer drugs and chemotherapy
• 5. It helps in saving anyone with snake-bite using its own venom. 

With these five reasons now, hope you understand why Hindus worship Nagas ( snakes) on Panchami ( fifth day of moon cycle) in the month of Shravan ( When frogs and rodents are plenty ).