Why is the double bass the only instrument in the violin family tuned in fourths?

Question

Out of the 4 instruments of the violin family (Violin, Viola, Cello, Double Bass), the bass is the only instrument tuned in fourths. The double bass is generally tuned in fourths, in contrast to other members of the orchestral string family, which are tuned in fifths.Why is it so, when the other three are tuned in fifths?

Answer 1

In contrast to the other instruments in the string family, the double bass is significantly larger. A fifth on the cello would equate to a second on the bass. That being said, even though the range of the open strings is more limited, the tuning allows for minimal left hand shifting.