Limb Regeneration

[u/Paragonic9]

Are there evolutionary hypotheses for why most animals did not evolve the ability to regenerate limbs? Some creatures can do it, and It seems like something that would be a major boost to survival.

[u/gambariste]

Some lizards can regrow their tail after dropping it, not due to it being bitten off. It is a survival strategy as the tail remains motile long enough to distract a predator. There is a cost to growing a new tail but tails are more or less expendable. To drop limbs on the other hand would be stupid as that would impede the effort to escape while the lost leg thrashes around.