I think you could use either one. Examples: That's a lot of snakes! There are lots of snakes! He knows lots of Spanish singers. He knows a lot of Spanish singers. I would say/write it either way.

a lot of and lots of have the same meaning: they both mean a large amount or number of people or things. They are both used before countable nouns and uncountable nouns: with countable nouns: A lot of people went to the game. Lots of people went to the game. with uncountable nouns: A lot of snow falls in winter. Lots of snow falls in winter.

Both can be used interchangeably: He has a lot of sisters. He has lots of sisters. The only difference is that "lots" sounds slightly less proper and more informal. "a lot" sounds slightly more correct in English. Both are commonly used.

Well it’s basically the same but you would use them differently in sentences. “I have a lot of goldfish in my fish tank.” Vs “I had lots of beer at the party.” The first is the more grammatically correct way to express excessive possession. Sounds more complete and mature.