Translation:They are elephants.
where do you take the 'these' from? You are giving much more context that provided. The only mandatory particle in English to make it grammatically correct [and coherent with the translation] is the pronoun 'they'.
Why isn't it 'Their elephants' or your elephants? Son is used with Ellas/Ellos as well?
their and your are possessive determiners, which are not used in the original sentence.
[ellos/as] son means [they] are. The subject is optional in Spanish and mandatory in English.