All limbs off ground (left), galloping freshie (below)

TYPE: Behaviour FUNCTION: Moving the crocodile rapidly away from a threat, usually towards the water. The fastest type of crocodilian locomotion - may reach almost 20 kph. INVOLVING: Front and hind limbs, although the tail probably acts as a counterbalance

C. johnstoni can accelerate from a standing start into a gallop [A and then 1], sometimes accompanied with a loud low-frequency vocalisation as it leaps into action, or it can transition into a gallop from either a high walk or a belly crawl. The "gallop" is actually more like the bounding run of a rabbit (both front and both rear limbs move in concert) than that of a horse (as the name would imply). The rear legs push down and backwards simultaneously, propelling the whole body forwards and slightly into the air [A]. As the hind legs push backwards in contact with the ground, the fore legs are lifted clear of the ground [A] and outstretch in front of and slightly below the chest [1 and B]. At this point, the entire crocodile is airborne! As the front of the body approaches the ground, the forelegs take the weight [C] while the back legs are lifted clear of the ground [2] and swung forwards [3]. The back feet usually contact the ground in front of the fore feet [4 and then D], where they provide maximum leverage when they push backwards again to propel the body further forwards [A and then 1]. So the cycle repeats. The specialised crocodilian ankle joint (discussed with the high walk) also helps to make this movement of limbs and feet possible.

(1) (2) (3) (4)

Galloping is as fast as a crocodile can go - typically 15 to 19kph in C. johnstoni. Galloping is twice as fast as a rapid belly crawl (8 to 10kph), and four times as fast as a typical high walk. Galloping is a very energetically demanding gait for a crocodile, and most C. johnstoni studied could gallop no further than 15 to 20 metres before transitioning into a rapid belly crawl or even stopping altogether. Usually, this distance and speed is enough to get the crocodile away from a potential threat, or into the water where it is much safer. Galloping also lifts the whole body clear of the ground, enabling the crocodile to leap any low obstacles in its path towards safety. While galloping requires enough strength in the limbs to power the body forwards in this manner, therefore, it does not necessarily require a high stamina for sustained galloping because each gallop only needs to be of short duration. Extinct crocodyliforms such as the Apatosauridae group of mesosuchians were far better equipped for a terrestrial mode of hunting than modern crocodilians, and it is perhaps in some of these extinct groups that galloping was more common, although the actual gait may have differed from that described here. As most modern crocodilians are primarily aquatic predators, speed and agility on land are no longer essential. The limbs of many species may also be too short or too weak to actually perform a gallop, although few studies have been done on crocodilian locomotion and it is likely that other species may also gallop in certain situations.