Introduction to A caballo regalado no le mires los dientes

Usually a gender (masculine or feminine) is assigned to a species. You cannot assume the gender of the animal by the name like you can with human titles (el profesor/ la profesora). If you want to be specific about an animal’s gender you can say that it is “macho” (male) or “hembra” (female). For example, the generic term for snake is “la serpiente”, but that does not mean that all snakes are female. You can specify with “una serpiente macho” or “una serpiente hembra.” For pets such as dogs and cats, you can change the ending to specify the gender: perra, gata, etc. There are only a few animals that have different names, based on their gender:

masculino femenino
caballo yegua
toro vaca
gallo gallina

Lastly, in English we have words for the baby animals such as kitten for a cat, or a puppy for a dog. But to make animals babies in Spanish you usually add the diminutive “-ito” at the end of the word such as “gatito” or “perrito.” There are a few animals that have specific names for their babies; most of them are farm animals and can be changed from masculine to feminine:

cachorro, cachorra puppy
gazapo, gazapa bunny
lechón, lechona piglet
cordero, cordera lamb
pollino, pollina baby donkey
potro, potra foal, filly
ternero, ternera calf