Lion’s mane jellyfish tops the tentacle length chart at 30 meters
The article explains what tentacles are (and how they differ from arms), then surveys the contenders for the longest tentacles. It notes measurement challenges in deep-sea creatures and abyssal gigantism. The lion’s mane jellyfish has tentacles that can reach about 30 meters, potentially the longest. Other notable long tentacles belong to the giant squid (tentacles up to ~10 meters), colossal squid (tentacles up to ~7 meters), and Nomura’s jellyfish (large in diameter with long tentacles). It also mentions giant Pacific octopus arms—long but technically arms, not tentacles—can exceed several meters, with records around 9.75 meters in length.
