I don't get the dog one at all. The article is about dogs getting smaller. Since neck size and weight are very correlated why bother to show both? I would just

I don't get the dog one at all. The article is about dogs getting smaller. Since neck size and weight are very correlated why bother to show both? I would just have a single plot showing the decline in dog weight over time. The fact that smaller dogs also have smaller necks is neither surprising nor useful.