Many lizards can break off their tails when they’re in danger. Many spiders can do the same to their legs. This is called autotomy. The body parts have in-built lines of weakness that can easily tear, and the wounds tend to rapidly close and heal. Usually, the limbs grow back. The animal temporarily loses a bit of itself, which is better than losing its life.

But these trade-offs aren’t always so straightforward.

As in lizards, these amputations are voluntary. If Mattoni anaesthetised the scorpions, or grabbed them by other body parts, the tail would never break.

The amputations are also common. Mattoni observed tailless individuals of eight more species, and he estimates that between 5 and 8 percent of wild Ananteris scorpions are