are there any animals "smarter" than a guinea pig?

Well to answer the first question, rodent wise, a rat tops the list. 

For your more updated question, animals like hamsters are most likely dumber than a guinea pig.

Hello,

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Finally, i want to be sure that guinea pigs are the smarter ones.

no guinea pigs are absolute galaxy brains

A lot of animals are smarter than Guinea pigs. Rats and dogs to name a couple.

Yeah.

Humans, rats, dogs, dolphins, chimps, elephants, squirrels... REGULAR pigs..

Smarter than guinea pigs: monkeys, dolphins

dumber than guinea pigs: insects, star fish, clams

I suppose a guinea pig might be smarter than a mouse, or a small bird like a sparrow. Smarter than a hamster for sure. Smarter than a gerbil too.

Yes. Opossums. And tigers. And crows. And finches. And herrings. And ...