The world’s largest animal is known to everyone: the blue whale weighs an average of 110 tonnes but can grow to 190 tonnes, and its heartbeat can be heard three kilometers away. Although it is in the forefront with its length of over 30 meters, the recorder is the line worm Lineus longissimus, of which a 55 meter specimen was found in 1864. But the smallest animal in the world is harder to determine – just because it’s not easy to spot.
Of course, only the smallest known animal is worth talking about, as new discoveries can re-order, and even previously discovered creatures can speak again. For example, the class of mucus spores (Myxozoa) has long been classified as an animal, previously thought to be unicellular. This changed only in 2015, and is now systematically a member of the Nettle Tribe.
However, no small animals are known today in mucus spores: most species of these jellyfish-like tiny parasites in fish or vertebrates do not grow larger than 20 micrometers. The smallest known mucus mite and the smallest animal is the Myxobolus shekel of the genus Myxobolus. The species described in 2011 are no larger than 8.5 micrometers. Just to make it easier to place this number: 1 centimeter 10,000 micrometers, or 8.5 micrometers 0.00085 centimeters. But as more and more mucus spp.
Within the range that is visible to the naked eye off the coast of India, the Psammothuria ganapati is the smallest of its four millimeters. It is a sea cucumber which, despite its name, is an animal and belongs to the echinoderms, like sea stars and sea urchins. The smallest of the former is the 5 millimeter Patiriella parvivipara, the latter is the 6 millimeter Echinocyamus scaber.
One of the smallest vertebrates is the frog Paedophryne amauensis Papua New Guinea, discovered in 2009, but only in 2012, the first scientific description. Adult individuals of the species have an average body height of 7.7 millimeters but do not grow larger than 8 millimeters – the smallest known vertebrate in the world to be approximately the size of a pea.
The smallest mammal is the Thai bat in Thailand and Myanmar, which grows to 3-4 centimeters by 1.5 to 2 grams. The Etruscan shark weighs 1.8 grams on average. The smallest known mammal that ever lived is a shark-like animal, Batodonoides Vanouteni, 53 million years ago, estimated to be only 1.3 grams. And the smallest of non-human primates is the Berthe mouse in Madagascar, with an average of 92 millimeters.