Why do the Texas rangers do the antler sign?

When a player does something connected to speed - such as stealing a base, or beating out a ground ball/triple - they make the antler sign to show they have speed, e.g., the Bengie Molina triple.

The claw, on the other hand, is a symbol of power, e.g., when Nellie Cruz brings out the Boom Stick.

The 'claw' represents a far away high five for a strong offensive play. While the 'antlers' come from 'run like a deer' after a stolen base or good base running.