Morphogenesis is traditionally regarded as the implementation of multiple genetic programs regulating cell differentiation rather than a complex biomechanical process involving cell-generated forces and tunable mechanical properties of the tissue. It has been shown that mechanics controls not only massive cellular rearrangements, as observed during gastrulation, but also pathological changes in tissue shapes such as those found in neoplastic transformation. In vivo measurements of endogenous forces and local mechanical properties during gastrulation are crucial to understanding how collective cellular movements arise during morphogenesis. Employing novel techniques that use fluorescent oil micro-droplets as in vivo force transducers and actuators, we quantify the spatiotemporal patterns of both forces and mechanical properties (tissue elasticity and fluidity) in different cell populations of the zebrafish embryo. Furthermore, we show that cell adhesion, cortical tension, and extracellular matrix composition affect different mechanical parameters in the tissue. The quantitative description of the embryonic force fields and the local mechanical properties will enable a better understanding of the interplay between signaling and mechanics, which in turn will facilitate the development of treatments for diseases, such as cancer, by restoring normal mechanical conditions within the tissues of interest.