07/28/2019
SCRUFFING - a (well-meaning) person commented on my previous photo, and I thought this reply was good enough to share.
Why scruff rats?
I've worked with assorted mammals, including rats, cats, and wildlife rehab, both professionally and as a serious hobbyist for years. Scruffing is a common technique across these areas for handling mammals. They have naturally loose skin there, and it is instinctual for them to relax when handled there by mothers. You'll often see baby rats being moved in this way! Their low body weight allows them to be scruffed safely as well as easily survive large falls. This is why a rat or squirrel can be scruffed safely while a large dog can't. (You see an increasing ability to survive falls and avoid other body-weight-related injury as the animal's body weight decreases. A surprising number of traits are connected to a species' body weight!)
Rats can be quite vocal about pain - they have vocal cues (such as squeaking) as well as body language cues, like the rat grimace scale. In addition, repeatedly scruffing a comfortable rat does not result in avoidance behavior. If they were in pain or distress, they would be conditioned to avoid the hand and would not relax. All of my rats with good temperaments are completely relaxed before, during, and after scruffing.
The purpose of scruffing these babies is to test temperament. My lines have been selectively bred for decades to be friendly and trusting towards humans. Rats that struggle during proper scruffing are distrustful of humans. I cannot use them as breeders, because I cannot in good conscience produce animals that might not be able to be handled safely and without stress. Sometimes, scruffing is necessary in an emergency: for administering medical treatment, for example. I select away from rats that show stress or distrust when being handled for necessary reasons. Rats that do not tolerate human scruffing are also often fearful or aggressive towards humans.
I hope this helps you to better understand why I do this as a breeder. I consider scruffing a useful tool in my handling kit to use when necessary.
Photo from Reddit.
