Buck Grease also called Sebum is an oily secretion from the sebaceous gland which helps to preserve the flexibility of the hair. Male rats (Bucks) will get an orange colored oily film on their skin which can become thick if they are sick and cannot groom themselves.
What Causes Buck Grease?
Many things can cause buck grease or sebum and not all male rats will get it. Just like with human teens, some get bad acne while other don't, the same analogy can be applied to the buck grease on rats. Most rats groom themselves many times a day which can lessen the amount of buck grease on their skin and fur, but if a rat is in pain, has hind leg degeneration or is just old, they will not groom as much and the buck grease can thicken on their skin. Some teenage rats get more buck grease when their hormones kick in but most times the amount of buck grease will diminish over time as their hormones even out.
How To Reduce The Amount of Buck Grease
While bathing might seem like the first thing to do, unless your rat is really dirty or smelly, bathing them can actually make their skin produce more buck grease or dry out their skin. If your rat is sick or has hind leg degeneration then you may have to bathe or wipe him down with a wet wash cloth if he cannot clean himself.
Two of my older male rats had a greasy back due to buck grease but they also had hind leg degeneration which made it harder for them to clean their back. I ended up taking a warm, wet cloth and wiping them down once a week which seemed to help keep the amount of buck grease down.
Sometimes the only sign of buck grease a ratty parent will notice is the skin on the back of their rat has taken on a slightly orange color, this is perfectly normal.