Long-necked dinosaurs, including diplodocus, had a gait that did not resemble any living animal, but most resembled a hippopotamus, according to a new study.
Researchers have studied the footprints of sauropods to learn more about their gait – the way they walked – in the De Queen formation of the Lower Cretaceous, Arkansas.
Like hippos, sauropods walked with a “diagonal gait” – in which each step of the front leg is in tandem with or very closely followed by the hind leg on the opposite side.
Using diagonal gait would allow dinosaurs to keep their wide frames in balance, the researchers found.
Sauropods were among the largest creatures to ever walk the Earth, with some weighing the equivalent of 14 African elephants.
Herbivorous dinosaurs have dominated landscapes during their existence, somewhere between 200 million and 66 million years ago.
Like hippos, sauropods walked with a “diagonal gait” – in which each step of the front leg is in tandem with or very closely followed by the hind leg on the opposite side. Elephants have the so-called “lateral” gait – in which two limbs on the same side of the body tend to move forward one after another
The sauropods walked with a “diagonal gait” – in which each step of the front leg followed closely from the hind leg on the opposite side (pictured)
Researchers analyzed fossilized footprints of a sauropod from three Cretaceous sites in Arkansas, where the tracks run in a straight line over distances ranging from 154 to 305 feet.
GAITWEAT USED BY MODERN ANIMALS
Diagonal gait
Hippos walk with a “diagonal gait” – in which each step of the front leg is in tandem with or very closely followed by the hind leg on the opposite side.
According to the findings of this new study, sauropods walked with a “diagonal gait”, similar to hippos.
Lateral gait
Elephants use a “side” gait in which two limbs on the same side of the body move forward one after the other.
So, the right front leg takes a step, followed by the right hind leg, then the left front leg, then the left hind leg, and so on.
Gait pace
Camels use the pace of their gait, in which the limbs on one side of the body (eg front right and back right) move together – almost at the same time, not one after the other.
Gait on one leg
Imagine that the foot makes a sound when it hits the ground – in a single walk the four legs make a steady rhythm: 1-2-3-4. The time between each stroke is the same.
Horses can be trained to use multiple gaits, but if they are not trained, the one leg is always the main one at normal walking speed, while the trot is the main one at faster speeds, and at even faster speeds there is a gallop.
By comparison, elephants use something called a “side” gait, in which two limbs on the same side of the body move forward one after the other.
So, the right front leg takes a step, followed by the right hind leg, then the left front leg, then the left hind leg, and so on.
The new study was conducted by Dr. Jens Lalensac and Dr. Peter Falkingham, researchers at Liverpool University’s John Moores.
“Everyone has always assumed that sauropods walk like modern elephants,” said Dr. Lalensac. A new scientist.
“But they didn’t, and we think that’s because the sauropods were much wider.”
Extinct animals, such as dinosaurs, have left traces that have been petrified, recording their movements at some point in their lives.
The position of the tracks relative to each other changes sequentially as the animal accelerates or decelerates.
This variation, which can be measured on long paths, is characteristic of certain gaits.
The four-legged use different gaits such as trotting, walking and pace.
In a trot, a pair of diagonal limbs (eg hind right and front left) move together, followed by the other pair of diagonal limbs.
Many mammals use trot when running, while reptiles also use trot at slow speeds.
Using LIDAR published images, the researchers analyzed fossilized imprints of a Sauropod from the Lower Cretaceous of three sites in Arkansas, where the tracks move in a straight line over distances ranging from 154 to 305 feet.
They found that the gait of the sauropod was most similar to the trotter, but also slightly different.
With the gait of the sauropod, the front leg touched just before the diagonal limb; when animals shake, both diagonal limbs land simultaneously.
But the study found that instead, sauropods used an intermediate gait between one leg and the trot – limbs on the opposite side tend to swing together.
The Sauropod dinosaurs (pictured) walked on all fours and had distinctive long necks. They were widespread – their remains have been found on all continents except Antarctica
Sauropods are the first successful group of herbivorous dinosaurs to dominate most terrestrial ecosystems for more than 140 million years, from the Late Triassic to the Late Cretaceous. They had long necks and tails and relatively small skulls and brains
Extinct animals, such as dinosaurs, have left traces that have been petrified, recording their movements at some point in their lives.
Researchers are estimating the limb phases of giant broad-leaved sauropod dinosaurs based on three long paths from the lower Cretaceous of Arkansas. In the photo, a graphic summary of the paper
Elephants place one foot almost directly in front of the other, leading to a narrow path.
In contrast, the paths of sauropods are much wider. Their special gait allowed the sauropods to have at least one foot on the ground on both the left and right sides of the body at all times, preventing them from swinging from one side to the other.
“Sauropods have chosen a gait that maximizes stability but still allows for efficient walking,” said Dr. Lalensac.
The study was published in the journal Current biology.
SAUROPODS: DINOSAURS WITH A LONG NECK AND A BRAIN
Sauropods are the first successful group of herbivorous dinosaurs to dominate most terrestrial ecosystems for more than 140 million years, from the Late Triassic to the Late Cretaceous.
They had long necks and tails and relatively small skulls and brains.
They stretched 130 feet (40 meters) and weighed up to 80 tons (80,000 kg) – 14 times the weight of an African elephant.
They were widespread – their remains have been found on all continents except Antarctica.
They had nostrils high on their skulls – instead of being located at the end of the snout like those of so many other terrestrial vertebrates.
Some fossils show that these nostril openings were so far up in the skull that they were very close to the eye openings.
Sauropods like diplodocus began to diversify in the Middle Jurassic about 180 million years ago.
Source: University of California Paleontology Museum