1. Shark corneas are being used in human eye transplants.
2. Dogs are about as smart as a two or three-year-old child.
3.  Butterflies have their skeletons on the outside of their bodies, this is known as the exoskeleton. 
4. Arachnophobia is the fear of spiders.
5.  Polar bears are the world's largest land predators.
6. Butterflies can only see the colours red, green and yellow.
7. Yellowtail is the general name for loads of different species of fish that have yellow tails or a yellow body.
8.  There are roughly twenty four thousand species of butterflies.
9.  A dik-dik is a tiny antelope that lives in East Africa, Namibia and Angola.
10.  Dik-diks weigh between three and six kilograms.
11. Female polar bears normally start having baby cubs at the age of four or five.
12.  Fireflies are also known as Lightning Bugs.
13. Even though a polar bears average body temperature is 37°C; they don’t give off any detectable heat, so they won’t show up in infrared photographs.
14. Dogs can see better when the light is low.
15.  Dumbledore isn’t only the Headmaster of Hogwarts; in fact a dumbledore is an old English term for a type of bee.
16.  Most young fireflies feed on nectar and pollen, although adult fireflies do not need to eat to survive.
17. 79% of pet owners sleep with their pets.
18. Two dogs were among the Titanic survivors.
19.  Many species of owls have special feathers for flying silently.
20.  An elephant can smell water up to 3 miles away.
21.  There is only one pink bottlenose dolphin which has been discovered, in an inland lake in Louisiana, USA.

These facts were found using the link below.

http://www.factsaboutanimals.net/