I have a boa constrictor at 4 years. When she was small i never heard anything but now i can sometimes hear a vissle sound from her breathing. It is when she is stressed and tenses her body. She dont like when i holding her with only my hands though she feel unsecure that she would fell.
I dont see any mucus or bubbles from her mouth or nose. And i have heard it sometimes for a long time (this whole year) so i dont think is respitory infection. She eat, poop, sheed and look healthy.
With any of the heavier bodied snakes when we are handling them we can put pressure on their lung. Whistles aren’t uncommon in this case. Especially if the animal is being defensive.
You can always try to obtain a swab of the mouth and throat to send out for testing if you have a concern. If they start to loose weight rapidly or are blowing bubbles. If the stools just don’t look right. If they start acting lethargic or twisting themselves around. Those are all reasons to definitely see a vet.
If your temps and humidity are correct though… Along with the snake not being social, it just sounds like the normal ‘hissing’ or ‘whistle’ they can make. My female retic is prone to it
Is she nearing a shed? I’ve heard that boas can sometimes develop a sort of whistling sound when they breathe when they’re nearing a shed. I assume it has something to do with the way the old skin separates from the new near the nostrils and creates some sort of vibration as the snake breathes. The sound usually disappears after they shed (though the sound may return on the next shed cycle).
I’ve never personally experienced this with my boa, but it seems relatively common with boas from what I’ve gathered from others.