Animals have various methods to protect themselves from their enemies: Some bite or sting, others secrete fluids or play dead. A small animal uses a completely different strategy that puts gymnasts on Olympic mats to shame: When in danger, the springtail (Dicyrtomina minuta) jumps backwards into the air and twists itself to a height of more than 60 times its body size in the blink of an eye.
“When globular springtails jump, they don’t just leap up and down, they flip through the air,” says Adrian Smith from North Carolina State University. “I wanted to see how they do it.” So Smith, along with a colleague, investigated the unusual abilities of these small animals. The results were published in the journal “Integrative Organismal Biology“.
40,000 Images per Second
To start a study on the jumping behavior of certain animals, you need some of these animals. Finding them was easy, according to a statement: “They’re all around us.” Smith recruited his animal subjects, only a few millimeters in size, from the leaf litter in his home garden.
But the authors did face a challenge: “Springtails jump so fast that you can’t see them in real time,” says Smith. If you try to film the jump with a normal camera, the animal appears in one frame and then disappears. “If you look closely at the image, you can see faint traces left behind where it jumped through the frame.”
So Smith used a special camera that could capture 40,000 images per second. He got the springtails to jump by illuminating them or gently nudging them with a brush tip. Finally, he examined their flight path.
Up to 368 Rotations per Second
The animals don’t use their legs to jump, but a body part called the furca. The furca is located under the abdomen, and the springtails essentially unfold it to jump. This allows them to perform a series of quick backward somersaults — at a peak of 368 rotations per second, according to Smith. “No other animal on Earth does a backward somersault faster.”
When the animals jump from a flat surface, they mainly move upward or backward, never forward. “Their inability to jump forward was a clue to us that jumping is primarily a means of escaping danger, not a form of general locomotion,” said co-author Jacob Harrison.
However, how successfully the animals actually protect themselves from their enemies through these acrobatic jumps remains a mystery.
