# Photo 21

# Photo 22

# Photo 23

# Photo 24

Yes, rats can laugh. Although we cannot hear their incredibly high-pitched laughter, scientists have discovered that they do make ultrasonic chirping noises. Rats express happiness and pleasure through this laughing-like action, demonstrating that they enjoy themselves much like humans. Fascinatingly, rats are less likely to contract and spread diseases and parasites than dogs or cats are. They are therefore healthy friends, even though they are not usually connected with hygiene.