Is there a way to tell if my pet has grown up if it has a name?

nethack

Use the FarLook command (;) on your pet, or a Stethoscope or Wand of Probing. It will say <petname> the <species>.

Related

What is a hyperjump?
Do overheard henchmen conversations point towards side quest goals?
Strange portal dropped a bunch of gold. How to make it reappear?
Does the "Sandstorm in a Balloon" have the improved double jump?
Why does the castle turn blue?
Does my hair color in Skyrim affect my werewolf color?
Will lvl 50 dwellers generate caps while in the vault?
Is Xbox Live required to play Minecraft on Xbox 360?
What CQC moves can you do in Metal Gear Solid V: The Phantom Pain?
Can I appear to be playing a Steam game without actually playing it?
Where is the best place to farm each of the rarer materials?
Can I craft a terminal to play holotapes in Fallout 4?