Long long ago, all pets were "pack animals," sort of. They could "fetch" and "drop" and some wild critters (white wyrms) would loot when wild and then have what they'd looted in their "packs."
Some of that was nerfed... I remember having a pet carry 4000 stone of hides. I remember pictures of dead white wyrms that had been carrying hundreds of items.
Pets stopped looting their kills.
"Fetch" was removed from the command set because people had been abusing it by having flying pets "fetch" runebooks in rune libraries, thus ruining the rune libraries.
The "pack" became limited to 125 items and 400 stone, whichever came first.
"Drop" was never removed. You can still have a bonded pet "drop" and the contents of its "pack" will drop onto the ground.
Most pets lost their "packs." A few pets remained where you could drop an item onto a pet and it would go into the "pack." The method for making a talking pet involved having a healing triceratops lion, or sabretooth that had never been dead. You could drop a communication crystal receiver onto that pet. With the communication crystal broadcaster in your own pack, you could make the pet appear to "talk," by whispering.
It was fun for a while.
With the new fix coming to your shard next week, you can't drop a communication crystal onto a pet and have it go into the pet's "pack."
Now I regret posting about the method earlier in this forum.