Daily Devotional – June 2
Prairie dogs are not dogs, but they are rodents classified with the squirrel family. They live in underground tunnels and chambers that create entire “towns” housing hundreds of prairie dogs on the plains of North America. Their underground tunnels contain multiple rooms - including bedrooms, nurseries, and bathrooms. These burrows even include a “listening room” close to the entrance, where the prairie dog listens for danger before going outside. One would think that the air would become stale in these underground burrows, however, the entire complex is nicely ventilated.
Each home has at least two openings. Prairie dogs surround these two holes with piles of dirt but always make one mound taller than the other mound. When a breeze blows across the top of these mounds, a pressure differential occurs, causing air to be aspirated up, creating a partial vacuum in the tunnels, and thereby drawing air into the lower opening. These prairie dogs have engineered a passive ventilation system that uses the Bernoulli principle! God created these animals with the instinct to build one mound higher than the other. This creates a draft or chimney effect that draws fresh air into the tunnel and allows it to circulate throughout. In essence, during the summer, the prairie dog town is “air conditioned.” When the above ground temperature exceeds 100oF, the burrow temperature one foot below is a comfortable 55oF. During the winter, the snow covers the “chimney”, not allowing the cold air to enter the tunnels. How does evolution explain this engineering ability? God gave the engineering instinct to these creatures, so they can survive extreme weather conditions found on the northern Great Plains.
To him who alone doeth great wonders.…
~ Psalm 136:4