This is such an embarassingly human centred headline: "The 'smart' animal club keeps getting bigger" - No! It was always huge!
It is humanity that is very slowly and reluctantly getting smarter at recognising the smartness of animals.
Also, please don't rank animal's smartnesses. That's just awful. Species are highly adapted to their environment. For some, that brings them closer to our very human - and thus not at al universal - definition of smartness. That's all.