Ducky the World’s Smallest Dog
They call him Ducky, but he is actually smaller then an average duck. Measuring at just 1.4 pounds (0.6 kg) and 5 inches (12.7 cm) tall, he was declared as the world’s smallest living dog by the Guinness World Records.

Smallest Cat
Mr Peebles may look like a kitten, but he is actually 2-year-old. The tiny cat got its size from a genetic defect that stunts growth. At just 6.1-inch (15.5 cm) high and 19.2-inch (49 cm) long, he currently holds certification from The Guinness Book of World Records as the world’s smallest cat.

Smallest Snake
The smaller they are the less frightening they appears to be. Resting on a U.S. quarter, the newly discovered Barbados threadsnake is the world’s smallest snake. This tiny reptile is measured at just 4 inches (10 cm) long, they can only be found on the Caribbean island of Barbados.

Smallest Hamster
Pee-wee is his name and he could easily make it his way in the Guinness Book of Records as the world’s smallest hamster. He weighs less than one ounce (28 g), measures at only one inch (2.5 cm) tall, and is only slightly bigger than a 50p coin.

World’s Smallest Cow
The world’s smallest cattle came is a rare breed of Vechur cows from India. The average height of Vechur cows is just 31 to 35 inches (81 to 91 cm). The photo below shows a 16-year-old Vechur cow with a 6-year-old HF cross-bred cow.

World’s Smallest Horse
Thumbelina was born May 1, 2001 at Goose Creek Farms near St. Louis, where Thumbelina’s parents breed miniature horses. She stands 43 centimetres (17 in) tall and weighs 26 kilograms (57 lb), and officially received the title of world’s smallest from the Guinness Book of World Records.

Smallest Seahorse
The creature is known as Hippocampus denise and is typically just half an inch (1.28 cm), a little bit smaller than most fingernails.

Tiniest Fish
Paedocypris progenetica is the scientific name for these tiny creatures and they are believed to be the smallest known species of fish and vertebrate in the world. The tiny fish below was measured at just 7.9 mm in length.

Smallest Crocodile
The Cuvier’s Dwarf Caiman or Musky Caiman is an alligator found in northern and central South America. The Paleosuchus palpebrosus reaches only a maximum length of 5.2 ft (1.6 m) in length and weigh up to 15 lbs (7 kg) making it the smallest crocodilian species in the world.

Smallest Turtle
Located in South Africa, the Namaqua Speckled Padloper tortoise is the smallest existing turtle known on earth. Their average length measures at roughly 3.1 in (8 cm).

Smallest Bat
Craseonycteris thonglongyai, also known as kitti’s hog-nosed bat can be found in the limestone caves of western Thailand. They are considered as the world’s smallest mammal. The tiny critter measures at 1.14–1.30 in (29-33 mm) in length and only weighs up to 4.4 lbs (2 g).

Smallest Bird
Bee Hummingbird got their famous name from, you guessed it, bees. With a length of only 2.25 inches, the Bee Hummingbird isn’t much larger than a bee. Their eggs are about the size of your smallest fingernail.

Smallest Flying Insect in the World
The parasitic wasp known as Dicopomorpha echmepterygis measures just a little over a tenth of a millimeter (0.139 mm).

Smallest Monkey
Roughly weighing 30 grams and measuring 2.5 in long, the Pygmy Mouse Lemur is the smallest living primate. They can only found deep in the forest of Madagascar.

Smallest Chameleon
Discovered on the rainforest floor of Nosy Be Island off the north-west coast of Madagascar, the tiny dwarf chameleon (Brookesia minima) is the smallest of the chamaeleonidae family. Some can be as small as 0.5-inch (1.2 cm) in length.