In this study we first evaluate the time between collisions related to the transport properties in liquid water, provided by the protons motion tied to the hydrogen bonds. As water is an essential substance for the establishment of life in the living beings, we take this time as the basic unit to measure some kinds of retention time related to their memory. Besides this, integration is an important feature associated to the operation of the memory. Then we consider two possible ways of doing integration and an average between them. One of these characteristic times, the Darwin time, is given by adding over the N basic units which forms the memory. The other possibility, the recent time, is obtained by considering a kind of time-like random walk running over the N basic units. Finally we perform a geometric average between these two times and call it generations’ time. As a means to estimate these characteristic times, we take the number of protons contained in a volume of water compatible with the dimensions of the portion of the brain responsible by its memory.