A lot of the comments here seem to be focusing on the definition of 'person'. The fact is, 'person' has always been a species-ambiguous term. Anything that exhibits 'personality' is a person, by some definitions.
That said, I get some very strange vibes from the way this article is written, especially give the subtitle that humans may not be superior. Some choice quotes:
>> Orcas, with their big brains, complex social structures, mysterious communications, and mind-boggling sixth sense, by their very existence, challenge the long-standing belief that human beings are the planet’s only intelligent occupants
"by their very existence, challenge the long-standing belief"... really? Why are any of these a true measure of intelligence?
>> Social life for killer whales, as we have seen, is deeper and more omnipresent than it is for humans
This is supposition, at best.
>> If orcas have established empathy as a distinctive evolutionary advantage, it might behoove a human race awash in war and psychopathy to pay attention.
Let's just ignore the way they can turn on one another and fight against other pods. Not to mention the truly brutal ways they hunt other species. So they show what we perceive as empathy. Let's apply that idea across all Orcas as if it were a rule, and then compare it to the worst humans in existence. Great.
>> The ability to experience positive emotions, like love and attachment, would mean that dogs have a level of sentience comparable to that of a human child
This is used as supporting proof, but when read by itself seems more like someone pointing out the obvious flaw of anthropomorphizing the actions of animals.
>> The “social cognition” that arises from this kind of richly shared experience of the world would even lead to a different sense of self than humans experience [...] The communal experience might actually change the boundaries of the self to include several individuals [...] This clearly indicates that dolphins—and particularly killer whales [...] have powerful emotional and empathic connection
So we're jumping from 'could and might' to saying the evidence 'clearly indicates' something?
I'm not trying to be overly negative, this article just strikes me as someone who is trying to twist what we know to suit their own agenda.