Nexop
These resilient insects can live for weeks without their heads, thanks to their decentralized nervous system and ability to breathe through tiny holes in their bodies.
Simple organisms like planarians lack complex organs and rely on regeneration for survival. Even if cut in half (including the head!), they can regenerate into two complete flatworms.
Tiny freshwater creatures, hydra possess amazing regenerative abilities. They can even be turned inside out and survive! Losing their head isn't a death sentence, as they can grow a new one.
These microscopic extremophiles are known for their near-invulnerability. They can survive extreme temperatures, radiation, and even the vacuum of space. Losing their head wouldn't be much of a challenge (for a very short time).
These spiny-skinned creatures have a decentralized nervous system, allowing some species to continue basic functions even after losing an arm (which can sometimes regenerate a whole new starfish!).
Similar to sea stars, brittle stars boast a decentralized nervous system and impressive regenerative abilities. While losing their head might be a major setback, they can survive for a period without it.
Another type of flatworm, turbellarians exhibit remarkable regenerative abilities. They can survive significant injuries, including head loss, and regenerate the missing parts.
Though losing their head wouldn't be ideal, some nematode species can survive for a short while without it due to their simple body structure and limited need for complex sensory input.
The venomous stonefish has a unique defense mechanism. When stressed, it can shed its head (along with its venomous spines) and grow a new one over time.
While not definitively proven, some scientists theorize that insects with segmented bodies, like some types of crickets, might be able to survive for a limited time without their heads due to their simple nervous system structure. However, this is still under debate.