A palaeontological measuring device

The determination of rock layers

Most trilobites lived in the sea. They came in many different sizes, from pinhead-sized trilobites to huge specimens that grew to nearly a metre long.

Trilobites, like most other arthropods, were at the beginning of the food chain. They had many natural enemies and initially hardly any means of defending themselves. Only their highly developed eyes, which were very similar to those of today's insects, were available to them to recognise potential enemies in time and take flight.

In the course of millions of years, however, the trilobites developed a hard shell, for their enemies difficult to crack, contributing significantly to the evolutionary success of the arthropods.

Trilobites are also extremely valuable to science for another reason: Since numerous trilobite species and forms are now known from many millions of years of Earth history, geologists use this knowledge to determine the age of rock strata. As soon as they find certain trilobite fossils, they can date the rock to within a few million years.