The objective of the present study was to investigate whether changes in type I collagen molecules have a direct impact on the biomechanical integrity of the collagen network and bone. In this study, demineralized and non-treated bone specimens were incubated at room temperature, and the collagen denaturing temperatures: 65 °C and 180 °C, respectively. Tensile tests and fracture toughness tests were devised and performed to assess the mechanical integrity of the collagen network. The correlations of heat-induced denaturation of the collagen network with the biomechanical properties of the collagen network and bone were investigated. The results of this study indicate that heat induced collagen denaturation has a greater impact on the stiffness and strength than the toughness of the collagen network. It consequently leads to significant changes in the strength and toughness of bone. The results of this study suggests that stiffness and strength of the collagen network are more related to bone toughness and strength.