'Fire Amoeba' Sets a New Heat Record for Complex Life at 63 °C
Incendiamoeba cascadensis divides at 63 °C (145 °F), a record for any eukaryote, widening where astrobiologists think complex cells could survive.
A newly described amoeba from Lassen Volcanic National Park in California can reproduce at 63 °C (145 °F), the highest temperature recorded for any eukaryote, the branch of life whose cells keep their DNA inside a nucleus. The NASA-supported study, led by Beryl Rappaport of Syracuse University, was published in Cell, and NASA Science reported it on September 22, 2026. The organism is named Incendiamoeba cascadensis, the “fire amoeba”.
The team found it in the park’s hot waters and tested its limits in the lab. It divides at 63 °C, beating the previous record of 60 °C held by some fungi and red algae. It stays active and keeps hunting for food at up to 64 °C. It can recover after five minutes at 70 °C, but not after exposure to 80 °C.
Most research on extremophiles, organisms that thrive in conditions lethal to most life, has focused on bacteria and archaea, simple cells without a nucleus. This result shows that complex cells can be tougher than assumed. For astrobiology, that widens the range of environments, on Earth and on other worlds, where complex life is worth considering. The caveat is scale: this is one species, a few degrees past the old record, and it says nothing directly about life elsewhere. It moves the boundary of what is possible, which is what the search for habitable places, including around other stars, depends on.
What to watch next: surveys of other hot springs may turn up eukaryotes that push the limit higher still.
Primary source
This summary is based on NASA Science and the peer-reviewed paper. Read the original for full details, data and caveats.
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