Hmmmm, have there been any changes in your household or neighborhood? Maybe construction outside or a barking dog? I’ve also heard sad stories of neighbors using those rodent- deterrents that emit a high pitched sound causing distress to rabbits.

Based on his age, there’s a strong possibility that this is all hormonal in nature (the peeing etc.), like he could be acting very territorial due to his hormones coming in strongly. In that case neutering will help a lot!  Lunging, snorting, and spraying urine are all territorial behaviors, and are different from what I would expect in a fear-based response to an outside noise or something like that. His behavior sounds like what Bun Jovi has done when Cooper (one of my other bunnies, who he isn’t bonded to) escaped his area and ended up in Bun Jovi’s territory.

This sounds to me like it could be about the phenomenon known as the “spook age”. It’s well known in young dogs, but most, if not all, mammals go through a similar stage in their development towards adulthood.

Very young mammals are unafraid and curious and teusting of their environment. They readily explore their surroundings and they dont mind being carried around or cuddled.

Then comes the next natural stage in the developement, when the young animal suddenly, and for no apparent reason, gets spooked by pretty much anything, even familiar things. A puppy dog can for example freak out at the sight of a tree trunk or a plastic bag blowing across the street. (We tend to notice it more with puppy dogs than with buns because we walk puppy dogs).

This “phobic” stage is transient and usually lasts only a short period of time. As Dana says, it’s about hormones and its fully natural.

The spook age can last from a couple of weeks to a couple oof months. Then these behavioural extreme merge together to form the adult personality.

An adult rabbit needs to be able to fend for itself. The absolute first priorities of an adult rabbit are a) to avoid becoming someone’s dinner, b) to make as many babies as it possibly can as soon as it can. Hence the often bordering on obsessive courting/ mating behaviour in young intact buns 🤣