[safeimp]

Not only mammals (hence, this post).

Read about it, mammals will yawn when other non-mammals yawn.

[lupusreal]

Well, the android is roughly mimicking a mammal. But more to that point, I've seen snakes yawn, and I then yawned. Reptiles generally seem to yawn and I'd bet they yawn when they see mammals yawn too.

[dinkblam]

> I've seen snakes yawn

if a see a snake (yawning or otherwise) i'll definitely not yawn.

puking, screaming or running would be more likely.