What are facts about seals they use their back flipper to push them through the water.?

It's not quite accurate to say seals use their back flippers to push themselves through the water. While the hind flippers are absolutely crucial for swimming, they primarily use their front flippers for propulsion.

Here's how seals swim:

* Front flippers: These are the primary source of power for swimming. They use their front flippers to "fly" through the water, similar to how a bird uses its wings. They beat their flippers in a powerful up-and-down motion to propel themselves forward.

* Hind flippers: These act more like rudders, steering the seal and helping with stability and direction. They can be used for short bursts of speed but are not the main source of power.

* Body undulation: Seals also use their bodies to generate thrust. They bend and flex their bodies in a snake-like motion, which helps them move through the water efficiently.

Therefore, it's the front flippers, not the back flippers, that are the main drivers of a seal's swimming power.