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Microanimals other than tardigrades

We are surrounded by microanimals other than Tardigrades, that are just as common, and with super powers of their own.

As soon as the trailer for Ant-Man and the Wasp dropped, everyone at Digit HQ gathered around a monitor to watch it. In the middle of the trailer, there is a lull in intensity which shows a vehicle of some kind in microscopic space. In the background, you can make out some tardigrades. In the first Ant-Man movie, just after Ant-Man takes down Yellowjacket, there is a sequence where you can see tardigrades as well, just before Ant-Man shrinks to the quantum realm. For a while, the team was discussing what is it with Ant-Man and Tardigrades. While we would like to see a fight with the nearly indestructible tardigrades, we came to the conclusion that the tardigrades were perhaps the most recognisable microanimals to show the scale at which Ant-Man was shrinking to.

The Tardigrade from the Ant-Man and the Wasp trailer.

Tardigrades, also known as water bears, are very hardy microanimals, that can survive in extreme conditions. They can survive drastic changes in temperatures or pressure, as well as exposure to radiation. An experiment by the European Space Agency demonstrated that they can survive in space as well. All of these attributes make tardigrades one of the most well known microanimals. However, we are surrounded by other microanimals, that are just as common, with super powers of their own.

A water flea. Image: PLOS One

Water Fleas
Cladocera, also known as water fleas are an order of tiny crustaceans that mostly live in freshwater environments. They smell through their antenna, which are sensitive enough to home in on hiding prey. There are hundreds of known species, but only about six hundred of them have been described. The microscopic animals are mostly transparent. They are born with a two eyes, which fuse into a single black compound eye, which is usually the only coloration on their bodies.

A copepod with its egg sack. Image: NOAA.

Copepods are a subclass of small marine crustaceans. Unlike the cladocera, the copepods are found in marine as well as freshwater habitats. Like all the other crustaceans, they have an exoskeleton, but since they are so small, these are thin and the animals are transparent. Most copepods do not have a heart or gill, and absorb oxygen directly from the ocean. Many have a single red compound eye. Copepods are so numerous, that the group might form the largest biomass on Earth.

A house dust mite. Image: Gilles San Martin.

Dust Mites
Dust mites are arachnids, and are commonly found in human dwellings. This is because they feed on human skin flakes and an average adult human sheds enough to feed one million dust mites every day. These tiny creatures, although invisible to the naked eye can trigger allergic reactions, or aggravate asthma. The dust mites are translucent, and there are about thirteen known species. These critters are the reason you need to change your bedsheets so often.

A lorciferan living in an anoxic environment. Image: BMC Biology.

Although lorciferans are multicellular animals, they are miniaturised and occupy about as much space as a protozoan, a single celled organism. They have brains, a digestive system, sense organs, and muscles, but lack a circulatory system. There are about 37 recognised species, and about a hundred more are known but not described yet. The lorciferans are the first known multicellular organisms to survive in an anoxic environment. They can spend their whole life without needing any oxygen. Previously, only viruses and unicellular animals were believed to have the capability to survive in anoxic environments.

A roundworm, or nematode.

The nematodes are a phylum, and are also known as roundworms. The nematodes are the most common multicellular organisms on the planet, and thousands can be found in a single handful of soil. There are over 20,000 described species, nearly half of which are parasitic. Not all the nematodes are microscopic, with some species reaching five cm in length, while some parasitic species can grow up to a length of three feet. When faced with harsh living conditions, nematodes can go into cryptobiosis, freezing all life functions till the conditions are favorable for living again. It is an ability that nematodes share with tardigrades and rotifers.

A rotifier. Image: Giuseppe Vago.

Rotifers are extremely hardy microanimals that live in aquatic environments. They can also be found in moist soil, living within the thin film of water around soil particles. There are tentacle like celia around the mouth of the rotifers, which looks like a wheel. The celia is why they get their names, which means “wheel bearer” in Latin. About 2,000 species of rotifers are recognised. Some species produce degenerated males that lack the capacity to even feed themselves. The males fertilise the eggs and die.

A spider mite.

Spider Mites
Spider mites are arachnids, belonging to the tetranychidae family. They are considered a pest as they can damage crops. They live on the undersides of leaves and plants, and can spin webs. The webs are not for catching prey, but instead to protect the mites from predators, while they feed on the plants. There are about 1,200 recognised species of spider mites. They reproduce rapidly enough to adapt to overcome most pest control measures.

The taxonomy of the listed microanimals
Aditya Madanapalle

Aditya Madanapalle

An avid reader of the magazine, who ended up working at Digit after studying journalism, game design and ancient runes. When not egging on arguments in the Digit forum, can be found playing with LEGO sets meant for 9 to 14-year-olds.