More likely the worry is other humans. We are territorial. Sleeping indicates a confidence in one's safety in a location. It can be a sign of dominance. Watch any cat sleeping in a dog's bed just to show who is in charge. I suggest that when in a new place we worried more about the locals not wanting us in their territory than the lions wanting to eat us.
It definitely made me ponder about Dunbar's number and what tribal life must be like.
Coincidentally, the three demarcations at this particular burn, the theme camp (~30 people), the field/block (~100), and the whole burn (~500), correspond to the lower end of the types of groupings Dunbar observed.
> Dunbar noted that the groups fell into three categories—small, medium and large, equivalent to bands, cultural lineage groups and tribes—with respective size ranges of 30–50, 100–200 and 500–2500 members each.