I think attributing it to one single thing is silly myself, this a month older and probably saw this or another form before regurgitating themselves elsewhere.
That's how it goes. At least we seem to be passed the days of people editing sassy Tweets to look like Bill Nye or some other well liked celebrity said them
In case someone like me was wondering, I just googled it. They build dams to bring up the water level and create deep ponds. They live in structures in the middle of the pond where they are protected from predators.