Swiss researchers uncover why some animals become fossils and others disappear

The decisive factor is the body of the animals themselves, the research team shows in a new study. The size and chemical composition of an animal can significantly influence whether it will be preserved as a fossil for millions of years, as the University of Lausanne (Unil) announced on Thursday. +Get the most important news from Switzerland in your inbox According to the study published in the scientific journal Nature Communications, larger and protein-rich animals have a significantly higher chance of becoming fossils. Large arthropods - animals with jointed legs such as insects, crabs or spiders - are therefore more likely to be fossilised than smaller, simply built animals such as certain flatworms or other worms that live in water. "It is therefore quite possible that some organisms could never be preserved in fossil form and that we will therefore never be able to observe them at all or only with great difficulty," explained Nora Corthésy, lead author of the study.