Watch male lions they sleep when they want, laze about all day until they need to eat. Or you can be a deer caught in the corporate wage slave, alarm clock prisoner headlights.
Also, as I mentioned in a sibling comment, humans hunt in a fundamentally different way to most predators, including lions: humans chase to exhaustion over hours while lions try to outrun their prey over minutes or less. (That's why humans have three gaits: walking, jogging, running, while most animals only have walking and running.)
In animals that do, you can bet that they have a way to wake together. If you're camping in the same tent as other humans you'll soon find that out. Alarm clocks are a workaround for not living communally with the rest of your tribe.