Since the noun is plural, shouldn't the answer have 'ces'?
No, I guess this is an exception. The French say "c'est" for singular and "ce sont " for plural.
Why not "ce sont vôtres animaux?"
"vôtre/vôtres" is a pronoun. Here you need an adjective.
I wrote "votre", I was corrected to use vos and on this discussion page it says "tes"? Am I confused?
The possessive adjectives, respectively for "vous" (polite singular or plural) and "tu":
votre animal (singular) - vos animaux (plural)
ton animal (singular) - tes animaux (plural)
It would actually be "ceci sont vos animaux"