A lizard tail trapped in 99-million-year-old amber shows the escape trick of dropping the tail is ancient

Lizards were already dropping their tails to escape predators nearly 100 million years ago, according to a study of a tail trapped in amber, Tel Aviv University said on 25 October. The study, published in Palaeontologia Electronica, provides the first direct soft-tissue fossil evidence of the escape trick.

A clean break, not a bite

The specimen is an 18-millimeter piece of amber from northern Myanmar holding a segment of scaly lizard tail about 99 million years old, from the middle of the Cretaceous period. Micro-CT scans showed a clean, symmetrical break surface framed by a wedge-shaped ring of muscle tissue, with no signs of tearing, crushing or splintering.

That pattern matches the muscle arrangement of modern lizards that shed their tails voluntarily, a behavior called autotomy. A tail torn off by a predator would show damage; this one came away along a built-in breaking point.

An escape mechanism already in place

The finding suggests tail autotomy was fully developed in lizards nearly 100 million years ago. Many living lizards use it today: the dropped tail can keep twitching and distract a predator while the lizard gets away, and the tail later grows back.

The researchers could not identify the species from the isolated tail. The study was led by PhD candidate Dolev Fabrikant and his supervisor Dr. Leonidas-Romanos Davranoglou of Tel Aviv University, with colleagues from the Volcani Institute and the National and Kapodistrian University of Athens.

Fossils keep revealing behavior as well as anatomy; this week a nearly complete 75-million-year-old ‘ostrich dinosaur’ skeleton from Utah went on study in public view. More fossil stories are collected under paleontology.