"Sock" is Tigger's cousin.
They're both orange with black stripes and have a Speech Impediment. They're also crazy, personality-wise. The only difference between them is that Sock is a real animal, and Tigger is stuffed.- Alternatively, Sock is related to Hobbes (from Calvin and Hobbes)
- Not likely, since he's a bobcat and they're both tigers.
Plato's Peak itself is the source of the animals' sapience.
Plato, Soc, Ari, and Aurora are the only talking animals in the show, and whenever we see animals anywhere other than Plato's Peak, they're inevitably shown to be non-anthropomorphic. Perhaps Plato's Peak itself has some kind of magical power that can make the animals living there more intelligent, which is why they seem to be the only ones of their kind that we see. Continuing on the above theory, Plato's Peak is a Native American sacred site.
Plato, Soc, Ari, and Aurora's species (bison
, bobcat, prairie dog and hawk) are all North American animals that are held in high regard in the Native American culture, which could mean that Plato's Peak was once a sacred place for Native Americans that inhabited Spring Valley in the past, thus explaining why it has a magical power that can make the animals living there more intelligent. What helps this theory is that one of the main characters - Annie - is a Native American herself.