[qwertyo]

I wanted to draw some things for my species, Pallio dogs. Here are situations in which a Pallio will have a short cape:

When a Pallio is wounded (top left), their capes will shorten. If things get worse though... the cape will disappear, and the Pallio with it. If they recover, then the cape will recover along with it.

A puppy Pallio (bottom) will have a naturally short cape, because the cape's length increases as a Pallio ages. An old Pallio would have a long cape then.

And finally, a Pallio can have a short cape even if nothing looks wrong (right Pallio). This Pallio has no clear injuries, but the short cape hints at something being wrong here. Possibly a disease of sorts.

So while you can use the cape as an indicator of age, it's not 100% accurate, due to many variables that can change a cape's length.