Okay I was watching a video about what a tuba is and in the video somebody said that a tuba essentially is a bugle but with valves because of the conical bore and it being a whole tube instrument able to play the fundamental. Now, I have never heard of a tuba being compared to a bugle. Usually when I think of a bugle, I think of a trumpet - the valves.
This is a bugle and I can see the similarities with a tuba except in length of tube. This is why I wouldn't compare a bugle to a tuba even though they are similar with that conical bore and whole tube instrument.
This is a tuba and you can see that there is a lot of tubing where the valves are. If you took away this tubing, yes, you would end up with a bugle but that extra length of tubing is also why the tuba can go so low, down to Ab below the bass clef for a contrabass tuba in Bb.
This is a trumpet, and yes it is a half tube instrument with a mostly cylindrical bore but it has a much more similar length of tubing to a bugle. And the pitch range is also very similar. In fact, especially in the military in TV shows, I see a bugle used as a valveless trumpet and I wouldn't be surprised if the trumpet evolved from the bugle.
So if it is so similar in pitch and use to a trumpet, why do I not hear it as being a whole tube version of a trumpet but rather as a valveless tuba when it is compared to other brass instruments? That valveless tuba comparison doesn't make sense to me.