1: 1. Dolphins stay alert 24/7, taking turns resting each brain hemisphere. 2. Bullfrogs can shut off their brains partially to rest while remaining alert. 3. Alaskan songbirds go without sleep during the summer months.

2: 4. Elephant fish sleep with their eyes open to ward off predators. 5. Brown bats rest suspended upside-down during daylight hours. 6. Ant queens delegate sleep duties to worker ants in their colonies.

3: 7. Horses take short naps while standing up to avoid predators. 8. Eared seals can stay in a half-awake state for extended periods. 9. African elephant matriarchs sleep the least among elephants, only 2 hours a day.

4: 10. Frigate birds can fly for months without sleeping by napping in short bursts. 11. Great white sharks rest by reducing brain activity while still swimming. 12. Walruses sleep floating in the ocean but occasionally sink to the seafloor.

5: 13. Hiking flamingos can remain standing while sleeping on one leg. 14. Giraffes have short bouts of sleep and can stay alert while standing. 15. Zebrafish can survive without sleep by taking small rest breaks throughout the day.

6: 16. Swiflets inherit the ability to rest with one eye open to watch for predators. 17. Humpback whales can sleep while swimming, half their brain at a time. 18. Koalas sleep up to 22 hours a day due to their low-energy diet.

7: 19. Common swifts sleep and mate while flying, covering thousands of miles. 20. Chimpanzees adapt their sleeping patterns based on external threats. 21. Houseflies can rest without fully shutting down their brains.

8: 22. Great horned owls have specialized brain structures for staying alert during sleep. 23. Some freshwater fish can survive without sleep for prolonged periods. 24. Texas horned lizards reduce brain activity during hibernation to conserve energy.

9: 25. Burrower frogs remain buried underground to avoid predators while napping. 26. Garden snails can stay in hibernation-like states for months at a time. 27. Tarsiers have evolved unique sleep patterns to adapt to their environment.