In this talk, I will discuss optimal control of two biological systems at different scales. The first part will focus on dung beetle navigation, while I will discuss temporal control of active fluids in the second part. In order to move in a straight line, dung beetles switch between egocentric strategies, continuously updating an internal estimate of the location, and geocentric strategies, using landmark cues to correct their trajectory. Applying optimal control theory to a minimal model, I will derive the switching strategy that maximizes the speed. I will discuss the role of environmental, execution, and sensory noise. Active nematic systems display turbulent-like motion when unconstrained. While this chaotic motion can be controlled in space by geometric confinement, achieving temporal control remains an open challenge. I will consider the dynamics of an active nematic confined in a channel made of viscoelastic material. For soft channels, the system produces spontaneous oscillations with periodic flow reversals. Notably, the temporal frequency of the oscillations can be manipulated by altering the mechanical properties of the surroundings, offering a guiding principle to control the dynamical behavior of active materials.