With a fixed energy, we investigate the motion of two nonlinearly coupled quintic oscillators for various values of the coupling strength with the aid of the Poincare surface of section. It is observed that chaotic motion sets in for coupling strength as low as 0.001. The degree of chaoticity generally increases as the coupling strength increases. However, regions of regular motion appear and disappear as the coupling strength increases.

Keywords: Oscillators, Quintic potential, Degree of chaoticity, Coupling, Poincare surface