The Internet’s newest must-see video doesn’t feature a frowning cat or a talking porcupine. Instead, “How Wolves Change Rivers” contains beautiful footage of Yellowstone National Park that illustrates how the reintroduction of wolves has changed the geography of the park. 

The video, which is part of a TED Talk given by environmental and political activist George Monbiot in September, was recently posted on YouTube by Sustainable Man, a popular blog that has a mission to spread ideas on sustainability. In just over a week, it’s had more than 1.5 million views.

Monbiot narrates the fascinating transformation that’s happened in Yellowstone since the wolves came back into the ecosystem in 1995. A “trophic cascade,” Monbiot says, starts at the top of the food chain and “tumbles all the way down to the bottom.” He describes how even though the wolves kill many animals, they actually “give life to many others.” Monbiot says that the wolves eventually even changed the flow of the rivers in the park, because the regenerated forests reinforced the banks.

But you don’t want to read about it. You want to watch it. Enjoy.

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