Not all questions for explanation are answered by referring to a cause. Yet many answers to questions like: Why is something the case? Why does this occur? do mention a cause or are phrased as a causal explanation. Salmon seems to suggest that even functional explanations might sometimes be reformulated as a causal one. As an illustration of a functional explanation he mentions the fact that jackrabbits in the southwestern part of the United States have extremely large ears because they constitute an effective mechanism for the temperature regulation these rabbits need in the hot, arid regions they inhabit. Following Salmon’s causal account of a functional explanation one could phrase the answer to the question: What is the cause of the long ears of the jackrabbits? as: The hot and arid nature of the habitat where they live. Understood in this way, it is the heat of the area that is the cause of the extremely long ears of the jackrabbits. Yet there are some problems with this kind of a cause. The causal connection between the heat and the long ears is of a different nature than the one between the heat and the rise of the body temperature. The functional explanation even rephrased as a causal one can hardly be understood just in terms of a physical cause and effect. The causal effect of heat in relation to the development of long ears depends on the goal or function they serve for the survival of the jackrabbit under the specific conditions of its habitat.