In this talk I will discuss some recent results inspired in the works of Palis-Takens and Palis-Yoccoz, about the unfolding of homoclinic bifurcations. In a joint work with A. de Carvalho, L. J. Diaz and K. Diaz-Ordaz, we study the variation of the topological entropy for a family of horseshoes bifurcating an internal homoclinic tangency. We prove that, restricted to a set of parameters with total density at the breaking-contact bifurcation, the topological entropy is a non-increasing function. This result formalizes the idea that the loss of transversal homoclinic intersections implies the decreasing of the amount of dynamics.