Can the locate command be used to find an entity?

The locate command is for structures, not animals.

The /locate command was added in Minecraft 1.11 to allow players to locate structures- such as woodland mansions and villages.

If you would like to locate your lost pet, you would have to teleport it to you. Use this command:

/tp @e[name=INSERT] @p

Replace INSERT with the name of your pet. Type it exactly as you created it, such as PenkatPet or Bob.