Regeneration

The impossible claim This animal has no heart, no blood, and no brain — and it can regrow its whole body from a single arm. The verified facts Sea stars (“starfish” — though they’re not fish) are echinoderms, cousins of sea urchins, and they break almost every rule we associate with animals: No heart, no blood — seawater is pumped through their water vascular system instead, and that hydraulic pressure is what powers the hundreds of tiny tube feet they walk with No brain — just a nerve ring around the mouth and radial nerves running down each arm They eat with their stomach outside their body — a sea star pulls a mussel’s shells slightly apart, everts its cardiac stomach through the tiny gap, and digests the prey externally before sucking the soup back in Regeneration: lose an arm, it regrows — weeks to months. Some species (Linckia) can rebuild an entire body from a single detached arm plus part of the central disc; full regrowth can take up to a year Most have five arms, but the sunflower sea star can carry up to 24 Watch 🎬 See the Short on YouTube — This Animal Has No Heart ...

The impossible claim Cut a planarian flatworm into 20 pieces and each piece regrows into a complete animal — eyes, brain, everything. They are functionally immortal. The verified facts The planarian (Dugesia, a freshwater flatworm, ~10–15 mm) is the regeneration champion of the animal kingdom. Cut one into pieces — as long as each fragment contains some stem-cell-rich tissue — and every fragment regrows into a complete worm: head, eyes, brain, mouth, all of it. ...