Runt

In a group of animals (usually a litter of animals born in multiple births), a runt is a member which is smaller or weaker than the others. Due to its small size, a runt in a litter faces obvious disadvantages, including difficulties with competing with its siblings for survival and possible rejection from its mother. Also in a domestic dog litter, most puppies would have to make room for the runt to get milk from the mother. Therefore, in the wild, a runt is less likely to survive infancy.

Even among domestic animals, runts often face rejection. They may be placed under the direct care of an experienced animal breeder, although the animal's size and weakness coupled with the lack of natural parental care make this difficult. Some tamed animals are the result of reared runts