Kangaroos hop, right? Well, not all of them.
Scientists said on Wednesday that a biomechanical and statistical analysis of fossil bones of a group of huge extinct kangaroos shows that the largest of the bunch in all likelihood could not hop as their modern-day relatives do with aplomb.
The study focused on a group of big-bodied, short-faced kangaroos called sthenurines that lived in Australia from about 13 million years ago until about 30,000 years ago, disappearing after the first humans arrived on the continent.
Photo: Reuters
These kangaroos were more heavily built than modern ones and had faces reminiscent of a rabbit. The largest, a species called Procoptodon goliah, weighed about 240kg, stood 2m tall and was 3m long.
The study found important anatomical differences in sthenurines’ limb bones compared with other kangaroos.
In terms of locomotion, they were unlike today’s kangaroos, with an anatomy ill-suited for hopping. They likely walked in an upright bipedal stance — putting one foot in front of the other, just like people — in a way modern kangaroos cannot, the study found.
This was facilitated by larger hips and knee joints as well as stabilized ankle joints, unlike today’s kangaroos, but like animals that walk or run. They also had a relatively inflexible spine not conducive for hopping.
“Today’s kangaroos mostly use hopping as their fast gait — although tree kangaroos rarely hop. But for slow speeds they use a type of ‘pentapedal’ walk, using all four legs and the tail,” said Brown University paleontologist Christine Janis, who led the study published in the scientific journal PLOS ONE.
With their stiff backs and specialized hands, this “pentapedal” gait would have been difficult for sthenurines. They also lacked certain specialized anatomical features of modern large hopping kangaroos, the researchers said.
Janis said she suspected smaller sthenurines used bipedal walking at slow speeds and may have switched to hopping at faster speeds.
“But the largest ones may have walked rather than hopped most if not all of the time,” Janis said.
Virtually all kangaroos today hop, although a species called the musky rat-kangaroo does not.
Australia is famous for its marsupials — mammals that carry newborns in a pouch on the mother’s abdomen, including kangaroos, koalas, wombats and others.
Procoptodon, the largest known kangaroo, lived from about 125,000 years ago to 30,000 years ago.
“Something the size of Procoptodon would have had a hard time hopping, if it hopped at all,” Janis said.
“Research on living kangaroos shows that they are close to the limit in terms of tendon strength while hopping,” she added.
Procoptodon lived alongside animals like the nearly hippopotamus-sized herbivorous marsupial Diprotodon, the “marsupial lion” Thylacoleo and the giant monitor lizard Megalania that measured roughly 7.5m long.
Scientists say Procoptodon and its group went extinct possibly because of hunting by humans, who arrived in Australia about 50,000 years ago, environmental changes wrought by people or climate changes.
With the midday sun blazing, an experimental orange and white F-16 fighter jet launched with a familiar roar that is a hallmark of US airpower, but the aerial combat that followed was unlike any other: This F-16 was controlled by artificial intelligence (AI), not a human pilot, and riding in the front seat was US Secretary of the Air Force Frank Kendall. AI marks one of the biggest advances in military aviation since the introduction of stealth in the early 1990s, and the US Air Force has aggressively leaned in. Even though the technology is not fully developed, the service is planning
INTERNATIONAL PROBE: Australian and US authorities were helping coordinate the investigation of the case, which follows the 2015 murder of Australian surfers in Mexico Three bodies were found in Mexico’s Baja California state, the FBI said on Friday, days after two Australians and an American went missing during a surfing trip in an area hit by cartel violence. Authorities used a pulley system to hoist what appeared to be lifeless bodies covered in mud from a shaft on a cliff high above the Pacific. “We confirm there were three individuals found deceased in Santo Tomas, Baja California,” a statement from the FBI’s office in San Diego, California, said without providing the identities of the victims. Australian brothers Jake and Callum Robinson and their American friend Jack Carter
Le Tuan Binh keeps his Moroccan soldier father’s tombstone at his village home north of Hanoi, a treasured reminder of a man whose community in Vietnam has been largely forgotten. Mzid Ben Ali, or “Mohammed” as Binh calls him, was one of tens of thousands of North Africans who served in the French army as it battled to maintain its colonial rule of Indochina. He fought for France against the Viet Minh independence movement in the 1950s, before leaving the military — as either a defector or a captive — and making a life for himself in Vietnam. “It’s very emotional for me,”
The Chinese Communist Party’s (CCP) Central Committee is to gather in July for a key meeting known as a plenum, the third since the body of elite decisionmakers was elected in 2022, focusing on reforms amid “challenges” at home and complexities broad. Plenums are important events on China’s political calendar that require the attendance of all of the Central Committee, comprising 205 members and 171 alternate members with Chinese President Xi Jinping (習近平) at the helm. The Central Committee typically holds seven plenums between party congresses, which are held once every five years. The current central committee members were elected at the