There are three hearts in an octopus. Blood is circulated by one heart, and pumped to the gills by another two. And the high copper content makes the blood appear blue.
Owls do not have eyeballs. They look through tubes in their eyes.
Polar bears have black skin. This helps it absorb heat from the sun to stay warm in an Arctic climate and presumably protects it from UV radiation.
Butterflies can taste with their feet, using chemoreceptors to identify vegetation. Females select the right leaf to lay eggs by "drumming" it with their feet to release fluids.
There are just approximately one-sixth as many taste buds in a dog as there are in a human, but their sense of smell is about 100,000 times more powerful.
In order to better see in the winter, when there is less light, reindeer eyes change colour to a bluish hue. This capacity has not been observed in any other mammal.
Mantis shrimp have claws that can speed up as swiftly as a.22 calibre bullet. Their fists are powerful enough to break glass, so researchers must house them in sturdy plastic enclosures.
A squirrel will never fart or throw up. No other rodent can either. Rat poison is successful because most other mammals will vomit up anything poisonous they consume.
Honeybees have been observed flapping their wings at a rate of 200 times per second.
Wild dolphins call each other by name. They let out a unique whistle to identify each other and will respond if they hear their own call played back.
The elephants' unique alarm sound is a universal symbol for humanity.