Unusual Facts About Tardigrades: Breathing Without Lungs and Surviving Even After Decapitation

Many of us feel fear or disgust when we spot a tardigrade at home. There are over 4,600 species of tardigrades worldwide, but only about 30 of these species are found in human habitats or homes. It is crucial to understand how powerful this tiny creature truly is. It has survived the Earth’s four major mass extinction events and even endured the effects of nuclear bombs. The history of tardigrades, which is millions of years old, is considered older than that of dinosaurs. In 1865, scientist Samuel Hubbard Scudder discovered fossils of tardigrade wings approximately 300 million years ago in American coal mines. At that time, the length of these wings ranged from 4 to 7 centimeters. In 2018, scientists at Imperial College London created a three-dimensional virtual model of these 300 million-year-old fossils, making it easier to understand the actual physical structure of tardigrades from that era.

The most remarkable trait of tardigrades is their extraordinary ability to survive. They have endured the four major mass extinctions on Earth. The Late Devonian extinction, about 360 million years ago, saw the destruction of approximately 75 percent of species due to severe oxygen depletion in the ocean, yet tardigrades survived. The Permian-Triassic extinction, around 250 million years ago, involved massive volcanic eruptions in Siberia, acid rain, and environmental devastation destroying 95 percent of marine species and 70 percent of terrestrial species. Tardigrades survived by hiding under swamps and feeding on decayed matter. The Triassic-Jurassic extinction, approximately 200 million years ago, caused by extensive volcanic activity, wiped out about 80 percent of life, but tardigrades once again managed to persist.

The body of a tardigrade is very different compared to other animals. It is divided into three main parts: the head, thorax, and abdomen. The head contains two eyes that provide an almost 360-degree field of vision. There are also two antennae that function as sensors. A tardigrade’s heart has 13 chambers. Interestingly, tardigrades do not have lungs; instead, they breathe through tiny openings called spiracles located throughout their body. Their blood lacks hemoglobin, so it is not red but rather white or yellowish in color. Remarkably, tardigrades can survive even after losing their head. Their nervous system is not confined solely to the head but spread throughout different parts of the body, with nerve centers allowing various parts to continue functioning even if one area is damaged.