The Basenji dog is the only dog that is not able to bark.
4
The reindeer is the only mammal that can see UV light.
17
A cat rubs against people not only to be affectionate but also to mark out its territory with scent glands around its face. The tail area and paws also carry the cat's scent.
293
Mosquitoes don't just bite you, they also pee on you.
11
Cows can sleep standing up, but they can only dream lying down.
745
The Pistol Shrimp can snap its claws together to create a sound of 218 decibels, louder than as supersonic jet at full speed. It only lasts for 1 millisecond. The snapping action also creates a bubble that is greater than 5000 Kelvin, close to the surface temperature of the sun.
21
In 1918, a homing pigeon saved over 190 American soldiers by delivering a message to nearby support despite having been shot through the breast, blinded in one eye, covered in blood, and with a leg hanging on by just a tendon.
22