1: "Dolphins use 'signature whistles' to call each other by name."

2: "Hummingbirds can fly backwards and hover in place."

3: "Elephants can communicate through infrasound over long distances."

4: "Octopuses have three hearts and blue blood."

5: "Cows have best friends and get stressed when separated."

6: "Giraffes only need 5 to 30 minutes of sleep in a 24-hour period."

7: "Penguins propose to their mates with a pebble."

8: "Peacock spiders perform elaborate dances to attract mates."

9: "Honeybees can recognize human faces and remember them."