Earth is full of giants, but “longest” doesn’t always mean “heaviest” or “biggest-looking.” Some of the longest animals might be as small as worms or jellyfish. Be it a thin ribbon like an animal drifting in the ocean, or colossal mammals longer than a basketball court. Many of these species live far from human eyes, in deep or cold seas, so much so that they glimpse into another world.
What makes them fascinating is not just their size, but how they survive, slowly pulsing, gliding, or hunting through dark waters. These long animals tell us how much of the planet’s life is hidden beneath the surface. Understanding them can deepen respect for fragile ecosystems and the need to protect them. Here are some of the longest animals known today.