Hannah Little describes a recent study of chimpanzees by Matthew Campbell and Frans de Waal [1]: "The path to empathy".
The study used 23 chimpanzees from two separate groups and they were made to watch videos of familiar and unfamiliar individuals yawning. Videos of the same chimps not yawning were also used for control. The chimpanzees yawned more when watching the familiar yawns than the familiar control or the unfamiliar yawns, demonstrating an ingroup-outgroup bias in contagious yawning.
In this case, the chimpanzee research leads that in humans; we don't yet know how extensive such biases may be. Campbell and de Waal do not mention the obvious difference between chimpanzee and human yawns as social signals: the canines. It would be very interesting if the yawn contagion is the same despite the obvious salience of canine teeth for chimpanzee yawning.