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
Vampire bats adopt orphans, and are one of the few mammals known to risk their own lives to share food with less fortunate roost-mates.
402
Pet dogs and elephants are the only animals that seem to instinctively understand human gesture.
14
Queen ants have one of the longest life-spans of any known insect - typically up to 30 years. Western harvester ant queens can live up to 40 years!
2
Cymothoa exigua is a type of parasite that enters through fish's gills, eats their tongue, and then replaces it.
6