Kissing releases masses of oxytocin, a "love potion" that helps couples bond and feel more attracted to each other.
13
When a male gentoo penguin "falls in love" with a female penguin, he searches the entire beach to find the perfect pebble to present to her.
25
There's a young hippo and a 130+ year old tortoise in a Kenyan wildlife preserve who are best friends and they even sleep and play together.
40
When dragonflies mate, their tails form a love heart.
22