Bass following each other

[bobsmitter03]

Could anyone tell me why after you hook a bass, another bass sometimes follows it for a little while? I have seen this happen when fishing by myself so there was no way that I could catch the other bass as well. On Sunday I was fishing with my dad when he hooked into a 20" bass. His line was out about thirty feet at the time when i remembered seeing that so, I made a cast right behind where his fish had just jumped and I hooked into a 15" bass. He thought I was trying to catch his fish if he lost it but, I was really trying to catch any trailing bass. Both fish were photographed and released.