Blue whale arteries are large enough for humans to swim through and their hearts are the size of cars.
12
When cats are happy, they may squeeze their eyes shut.
10
The reindeer is the only mammal that can see UV light.
17
A scorpion can hold its breath for up to 6 days.
19
Cows can sleep standing up, but they can only dream lying down.
745
Female kangaroos have three vaginas.
2
Dolphins can rapidly heal from extreme injuries, such as shark bites, and regenerate their original body shape.
19
Dogs have been man's pet for over 14,000 years.
224