Survival skills
A human being can survive an average of three to five days without the intake of water. The issues presented by the need for water dictate that unnecessary water loss by perspiration be avoided in survival situations. The need for water increases with exercise.
Life on Venus
It is plausible that microbial life originated on Venus if liquid water existed on its surface prior to the heating of the planet by the runaway greenhouse effect, but no longer exists. Assuming the process that delivered water to Earth was common to all the planets near the habitable zone, it has been estimated that liquid water could have existed on its surface for up to 600 million years during and shortly after the Late Heavy Bombardment, which could be enough time for simple life to form, but this figure can vary from as little as a few million years to as much as few billion. This might also have given enough time for microbial life to evolve to be aerial. There has been very little analysis of Venusian surface material, so it is possible that evidence of past life, if it ever existed, could be found with a probe capable of enduring Venus's current extreme surface conditions, although the resurfacing of the planet in the past 500 million years means that it is unlikely that ancient surface rocks remain, especially those containing the mineral tremolite which, theoretically, could have encased some biosignatures.