[small_model]

If you watch birds you will see they don't use alarm clocks nor go to work, but still find food each day.

[quietbritishjim]

Birds don't need to cooperate in groups to find food.

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.