The Caterpillar D10T "push-cat". It's a powerful machine with a specialized purpose. It doesn't push dirt, it pushes scrapers.
The small curved blade is designed to work with the push plate on the back of the scraper, allowing for all the dozers power to be transferred. Additionally if you look really closely, just behind the blade are shock absorbers to absorb the impact of when the blade first makes contact with the scraper.
This machine typically only pushes single engine scrapers since it allows the scraper to engage the ground in a far more effective manner. This allows for quicker cycle times and scraper spreads are all about speed.