Here's why:

* Galvanometers are sensitive instruments that detect and measure small electric currents. They work by using the magnetic field produced by a current-carrying coil to deflect a needle or pointer.

* Ammeters are also used to measure current, but they are designed to handle larger currents than galvanometers.

* Voltmeters measure voltage, which is the potential difference between two points in a circuit.

So, while an ammeter can also detect the presence of current, a galvanometer is the specific device designed for that purpose.