A banana slug can be 6-8 inches and their erect penis can be just as long. Also, their penises emerge from their heads. After sex, banana slugs eat each others penises.
17
A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
Dogs sometimes fake being sick to get attention.
26
Dolphins can rapidly heal from extreme injuries, such as shark bites, and regenerate their original body shape.
19
A dog's naked behind leaves absolutely no bacteria when pressed against carpet.
250
Blue whale arteries are large enough for humans to swim through and their hearts are the size of cars.
12