In my experience male rats that do become aggressive are usually aggressive towards other rats and need a neuter so they can continue to live safely with others and because the hormones are really interfering with their quality of life.
Most male rats do not need to be neutered. Some people, such as myself neuter all their rats, while other people do not get them neutered unless there is a problem.
When rats are neutered it is extremely important to have a good vet with the knowledge and experience to do it safely ….. only gas anesthetic is used and nothing is given by injection until after the surgery when the rat is given an injection of metacam to control pain for 24 hours (after 24 hours oral Metacam is given for pain control)
All surgery is a risk, but with a good vet who has the experience and knowledge to safely neuter rats, the risk is low.
Rats that have bitten me have usually been recently rescued rats that are terrified, or rescued new mothers trying to protect their babies.
I have had lots of male rats. Only one of them has shown a little aggression, and for some reason it was towards a shoe! He peed on my son's shoe, and my son wiped it off, then pepper jumped and attacked the shoe, all the while squeaking and squealing. Then, a couple mins later, he was fine. Pepper kind of looked like a shark, so we call it the great shark attack. We still to this day have no idea what his problem was, but it was freaking cute and funny. He never bit, just tossed his face around on the shoe and squeaked at it while jumping different directions. But then again, maybe I've been fortunate.....
No they do not. They are lovely pets and loving animals. They deserve handling and outside of their cage time. I hold mine on the couch and allow them (males) to roam back and forth on the couch. I bring tissues or damp paper towels to clean up any droppings. But otherwise it's great interaction and bonding and good for you and your pets relationship.
The more they are in the cage and not handled, will dictate their behaviour and that goes for any gender or breed.
I have had two male rats in the past who were intact and they were sweeties to me and each other if I were you I would wait to neuter unless you see issues or get any females in the mix. Don't fix what's not broken, right?
My son was wearing a shoe, but I guess same concept....LMAO. The image of him squeaking and jumping and rolling around is one we can't get out of our heads! Pepper was a character!
Now taco, my biggest, fatest (and almost 2 years old) boy, will sometimes puff up at skittle, and bump him with his sides, and stomp his front feet at him. I do know this is aggression, but he ONLY does it when skittle tries to jump on his back, or tries to hump him. In this case, I think he's more so doing it to put skittle in his place. There has NEVER been bites, cuts, blood, or fur flying. And after its all over, taco will bounce off and play with skittle as if nothing ever happened.
So I wouldn't worry TOO much if you do see what you think may be hormonal stuff. Only if it gets to a certain level or becomes problematic.
A lot of it depends on your area and the care put into the temperament of the rats. In Ontario we have a lot of rat mills and backyard breeders and see a high incidence of hormonal aggression in our boys but it doesn't mean most will become this way. If your boy is sweet and normal at 5 months you should be okay. I find 5-6 months and you are already seeing signs of it. More agitated, especially with cagemates, chases and more violent pinning and wrestling among cagemates, puffed up fur, chattering teeth, hunched backs, sidling, digging with front paws and rubbing against objects to scent mark them, nipping humans or biting them. These are all signs. I'll dig out a pic of a young lad who became hormonal very young and after a neuter when he was lovely and sweet again
They have a huge cage and it's in my living room I talk to them all the time or take them out to get treats. Or section off the hallway and let them have free range. Artan is a sweetie he prefers climbing on me when I'm sat down and then will navigate onto shoulder. He doesn't prefer hands. I pick him up for a scratch and power groom him to cement my alpha status. Caius is like a bar of soap but I groom him as well. Hands equal yogurt drops. They always come to cage doors to see me when they hear me
Rats are some of the sweetest, easiest to handle rodents in my experience. Even pretty stressed out rats rarely bite. Domestic rats are very gentle. There's some rats out there who have trauma or other issues that need some gentle patience, but genuine biters seem pretty rare.
14/16 of the rats I've owned have been intact males, just generic feeders/pet store mill rats and if anything they only became more mellow with age. I've had some issue with rats becoming aggressive towards each other, but never towards me. Most of them just end up becoming more soft, and kind of couch potatoes in their old age...