How does the mechanism of caudal autotomy work?

Caudal autonomy refers to the ability of animals to drop their tails in response to predator attack. Later, the tail can regrow, assuming that the animal was successful in eluding its attacker. In some cases, the severed tail can keep moving, resulting in further distraction.

There are two mechanisms depending on whether the break happens between two vertebra, or along a pre-existing fracture plane (intravertebral). Sphincter muscles may contract around the caudal artery to minimise bleeding and skin flaps may close around the wound site to reduce infection.

https://www.nature.com/articles/s41598-018-21526-3

https://en.wikipedia.org/wiki/Autotomy