How did tetrapods walk?

An ancient four-limbed creature that's thought to be the first ever to walk on land couldn't actually walk at all, researchers have discovered. Instead, they think the animal, called a tetrapod, simply hauled itself out of the primordial ooze with its two front limbs, using its back limbs merely for balance. 'These early tetrapods probably moved in a similar way to living mudskipper fishes in which the front fins, or arms, are used like crutches to haul the body up and forward,' explains Dr Stephanie Pierce from the University of Cambridge and The Royal Veterinary College, lead author of the study. The shift from swimming to walking was a pivotal step in the evolution of land-dwelling animals like us. Rather than fins, creatures destined for the land had to develop limbs, which are essential for getting about. Early tetrapods ticked this box. So scientists assumed that because they had four limbs — instead of fins — they could walk, 'a bit like a salamander.' The idea was that they'd do this by coordinating each limb in a sequence just like today's four-legged animals.