You've probably seen videos of cats picking up their kittens by the scruff of the neck so they can carry them more easily. This is a great way for cats to transport their kittens when they aren't old enough to move by themselves, and kittens will naturally go limp and submissive when someone applies pressure to their scruffs.
For this reason, many people think that it's fine to pick up a cat by the scruff of its neck using their hands, but there are a number of reasons why this should be avoided. Here are just three.
1. Your Hand Isn't Properly Equipped
It might seem as if your hand would be a far safer carrying device than a cat's mouth; after all, your hand lacks all those sharp teeth. However, cat's mouths are actually perfect for the job since cats have pressure sensors beneath each tooth. This means that they are able to apply the perfect amount of pressure to the scruff to carry a kitten without hurting it. Without such innate equipment and ability, people often squeeze the scruff too hard.
2. Adult Cats Have Larger Bodies
One of the reasons why cats can safely pick up their kittens by the scruff without hurting them is that kittens have such small, light bodies. This means that very little pressure is placed on the joints of the neck. However, cat's bodies obviously get heavier as they grow, so it becomes more and more uncomfortable and unhealthy to suspend all a cat's bodyweight by the scruff.
3. Other Handling Methods Build Trust
Some cats do not like being handled in any way. In such cases, it may sometimes be necessary to handle them by the scruff. However, many cats can be trained to be picked up and handled, especially if you start at a young age, but this requires trust to be established between owner and pet. Unfortunately, it's very hard to establish trust with a cat when you are picking it up by the scruff. This might make a cat act submissively towards you, but it isn't a comfortable sensation. If you want to be able to develop a bond with your cat strong enough that they'll let you cradle them and carry them around, picking them up by the scruff of the neck isn't a good way to go. In fact, cats can become aggressive if you keep picking them up this way.
Talk to your vet for more information.