I wouldn't say all animals are smarter than humans, but some of them most definitely are. It is well known that animals have a keener sense of smell, sight, and hearing than most humans. Animals seem to sense danger more quickly than humans, as well, and are also very cautious. Many humans tend to fail miserably in these areas.
Humans pride themselves on being the smartest, most advanced species on the planet. However, the depth of human stupidity is demonstrated on a daily basis. Humankind's pride, greed, and lust for violence is a clear flaw, and animals have been proving their own cunning, resourcefulness, and sheer skill at survival for centuries. Animals are certainly smarter than humans, just in different ways.
The article doesn't even mention any indications of intelligent it just says they live longer out of captivity. That's not even mentioning what you consider to be a good source of scientific information to be a random Sunday magazine. Animals have much poorer problem solving and creating skills and they only use basic tools. When a chimp discovers general relativity you can tell me it is smarter than the average human.
If animals were smarter than humans, we wouldn't be dominating the Earth. People have taken over the planet and have evolved over the years. We know how to communicate, how to live comfortably, and have designed technology that animals could never have a chance at. Animals all have their own unique skills, but humans are definitely the smartest species.
Humans have one thing that makes them smarter than humans. That is that they have consciousness. Humans know that they exist. They have a free while. Animals might have very good basic instincts, and an ability to live longer than humans, but that doesn't necessarily make them smarter, just programmed differently.