Any ideas why Vekrengs whistle?

https://preview.redd.it/so3av6zsr91g1.png?width=1080&format=png&auto=webp&s=f15d267551fe54d2eb7f54e658a3639a0c88be4f

https://reddit.com/link/1ox56f4/video/0qr6g9ytr91g1/player

https://preview.redd.it/3794ak9wr91g1.png?width=676&format=png&auto=webp&s=22e43f8c39f1528a6f3dc56095b22eb3fb952a63

"Erm actually ☝️🤓 they don't whistle" YES THEY DO! You ever hear that whistling in the plains? Wondering "what the heck is that??" It's the cloaked panthers! But the hunter's guide says nothing about it. But I know it's them that are doing it. So why?