Serpiente vs. culebra

The words 'serpiente' and 'culebra' in Spanish both refer to 'snake' or 'serpent' in English. While they are often used interchangeably in casual conversation, there are subtle differences between them in terms of the types of snakes they depict.

Serpiente

'Serpiente' is a broad term that encompasses all types of snakes, including venomous and non-venomous ones. It is equivalent to the English word 'snake'.
La serpiente es un animal muy temido por muchas personas.
(The snake is an animal that many people fear.)
La serpiente cobra es una de las más peligrosas.
(The cobra snake is one of the most dangerous.)

Culebra

'Culebra' refers typically to smaller, non-venomous snakes. In some regional dialects, it can also refer to any snake, but this usage is less common.
La culebra de jardín no es peligrosa.
(The garden snake is not dangerous.)
Las culebras suelen ser más pequeñas que las serpientes venenosas.
(Snakes are usually smaller than venomous snakes.)

Summary

'Serpiente' and 'culebra' are both Spanish words that translate to 'snake' or 'serpent' in English. However, there are subtle nuances between them as 'serpiente' could mean any type of snakes while 'culebra' generally refers to smaller, non-venomous snakes.