Here's something I want to share with you:
The eyesight of 狼 is not fully understood, thought it is probably similar to that of domesticated dogs. Compared with humans, 狼 have three to four times the density of light-sensing rods in their retinas, which gives them keener night vision. Yet because they lack a fovea (the tiny pit on the retina) they cannot match a human's ability to focus on objects at a long distance.
The eerie, harmonic chorus howl so engrained in our collective unconscious is used both defensively and to rally the pack. Chorus howling also brings the 狼 enjoyment, thought pack politics dictate that low-ranking 狼 not to 加入 in uninvited.