What are dslr camera bodies black?

I want to buy a nikon D5200 camera. Are black camera bodies preferred more by people or other colours like red and bronze

The color of a camera body is strictly aesthetic and serves no real purpose other than for looks. Generally, point-and-shoot cameras have colored bodies because they look more fun whereas more professional bodies are typically in black just because they look more "professional".

There are not a lot of bronze bodies, and only a very few red ones. Way back in the day, entry and consumer level SLRs were silver and the pro cameras were black. It was just a matter of marketing. There are a few silver bodies out there, usually with black grips and the like. It is purely a marketing decision.

There's some basis for camera bodies being black. Many times a photographer wants to be as inconspicuous as possible, and flashing around a big red or white or blue camera does not help in that regard. Still, as Adam said, some of it just comes down to the black seeming more "substantial" than a colored body. Many toy cameras come in different colors, and when someone spends hundreds or thousands of dollars on a camera, they don't want it confused with a Holga!

Pentax does, however, make some DSLR cameras in various colors. Also, the uber expensive Hasselblad digital cameras have been available in colors such as titanium and a special Ferrari red model.

I don't like bright, garish camera colors, but I agree that I don't see that it would hurt a thing if manufacturers could make the cameras look better with something more elegant looking such as a gun metal grey or carbon fiber body.

For reasons long forgotten black became the color of choice for cameras used by professional photographers several decades ago. One reason may have been the belief that a black camera is less conspicuous and therefore draws less attention. Pentax has been going against that trend with their K-30 DSLR cameras available in Black, White or Blue. Pentax has even marketed their white body camera as more appropriate for wedding photographers. Another reason may have been that Leica 35mm rangefinder cameras were black and often used by professional photographers.

It has to do with aesthetics in that it looks more professional and serious, but also that body doesn't reflect light therefore preventin any unwanted glare that may appear on the subject.