Among the smallest seahorse species, it typically measures less than 2 cm (0.8 inches) in height.
The world's smallest tortoise, found in South Africa, with adult males measuring as little as 6 cm (2.4 inches) in length.
One of the smallest primates, the pygmy marmoset can be as small as 117 mm (4.6 inches) in length, excluding the tail, and weigh about 100 grams (3.5 oz).
The smallest shark species, found in the deep waters off the coasts of Colombia and Venezuela, it can grow up to 21 cm (8.3 inches) long.
A fairyfly found in Costa Rica, it is one of the smallest insects, with a body length of only about 250 micrometers (0.0098 inches).
A species of chameleon from Madagascar, among the smallest reptiles, adults can be as small as 29 mm (1.14 inches).
Also known as the bumblebee bat, it is one of the smallest mammal species by size, measuring about 29 to 33 mm (1.14 to 1.30 inches) in length and weighing about 2 g (0.07 oz).
The smallest mammal by mass, the Etruscan shrew can weigh as little as 1.2 g (0.042 oz) and measures about 36 mm (1.4 inches) in length.
The smallest bird, native to Cuba, the male bee hummingbird can be as small as 57 mm (2.24 inches) in length and weigh about 1.6 g (0.056 oz).
A tiny fish found in Indonesia, it's one of the smallest vertebrates in the world, with mature females measuring just over 7.9 mm (0.31 inches) long.