There are a few species that might carry their young in a way that looks like they are holding them by the neck, but this is usually not the case. For example:
* Cats: Mothers sometimes carry kittens by the scruff of the neck, but this is more about control and support than actual "holding" by the neck. The scruff of the neck is a sensitive area that allows the mother to easily move the kitten without hurting it.
* Birds: Some bird species will carry their chicks in their beaks, but again, this is more about support and transportation, not actually holding the chick by the neck.
In general, animals have evolved different strategies for carrying their young based on their species and environment. This usually involves methods that are safe and comfortable for both the mother and the offspring.