Animals that don't have sound sleep during night

These animals don't have sound sleep through out the night.  They would be having short periods of sleep. 

It is mainly to avoid predators. 

Some of such animals are   - - - - - 

1. Ants

2. Horses

3. Sharks 

4. Deers

5. Elephants 

6. Walruses 

7. Giraffes

8. Dolphins