LAND MAMMAL: The bumblebee bat tips the scales at about 2 grams and measures between 30 and 40mm as an adult.

MARINE MAMMAL: Sea otters weigh between 35 and 90 pounds.

BIRD: The hummingbird, grows to only 6cm long.

FISH: The Paedocypris progenetica, which was recently discovered in Indonesia, measures just over 8mm.

REPTILE: The British Virgin Islands gecko is about 1.8cm long when fully grown.

INSECT: Fairyflies are only about 1/5 of a millimeter long.

http://www.factmonster.com/ipka/A0934316.html