Because he got cold feet.
Because she wanted to try out her new spring suit
That's when dinosaurs are jumping out of palm trees.
Sir. Groan worthy penguin jokes(https://allwrong.wordpress.com/2007/10/05/penguin-riddles/)
Igloos it together!
A Puthy
They always get cold feet! I'll show myself out.
Iceberg
Because only the top 1% can stay above water.