The lens he uses in this picture is 70mm-200mm. I have a lower end equivilant of this variety of lens (70-300mm) and at full extension at 300m, the lens alone measures roughly six inches long.

His lens though is probably much better in quality and range, and probably can shoot at high shutter speeds and a broader aperture (both elements that affect how much light is let into the camera).

To say the very least, this photographer was probably waiting in the grass for minutes, if not hours to get the right picture. Back to what I said earlier, depending on how far he zoomed in on the tiger, he could be steadying that in his hands for a long time, provided he doesn't have a tripod.

Also, he probably has the camera set at a higher shutter speed to catch all the water particles in motion, so (apart from possibly calibrating other camera settings to compensate his high shutter speed) when he's shooting this picture, he probably has multiple pictures of this one second that he has to sort through and determine which is best. Usually from a shoot like this, the amount of pictures in your workflow can number hundreds or even thousands.

So, as a tl;dr: This guy put a lot of time and effort into this picture, and it's pretty damn good, especially compared to those dinky little point and shoot cameras everybody has. Screw your opinion for thinking this is a sub-par picture.