Fun Fact Friday (#75)

Fun Fact Friday is a meme hosted by Lettora at I’m Booked! If you’d like to join and do your own Fun Fact Friday, just ask! At I’m Booked! Every week we’ll give you five new, fun facts. 
This week’s five facts:

1. 2% of people have armpits that never smell because of an unusual genetic variant.

2. Hippos produce red sweat which acts as a sunscreen against UV rays.

3. Human saliva has a boiling point three times that of water.

4. A baby spider is called a spiderling.

5. Slugs have 4 noses.