WASHINGTON (AP) — Muddy footprints left on a Kenyan lakeside suggest two of our early human ancestors were nearby neighbors some 1.5 million years ago.
The footprints were left in the mud by two different species “within a matter of hours, or at most days,” said paleontologist Louise Leakey, co-author of the research published Thursday in the journal Science.
Scientists previously knew from fossil remains that these two extinct branches of the human evolutionary tree – called Homo erectus and Paranthropus boisei – lived about the same time in the Turkana Basin.
But dating fossils is not exact. “It’s plus or minus a few thousand years,” said paleontologist William Harcourt-Smith of Lehman College and the American Museum of Natural History in New York, who was not involved in the study.
Yet with fossil footprints, “there’s an actual moment in time preserved,” he said. “It’s an amazing discovery.”
The tracks of fossil footprints were uncovered in 2021 in what is today Koobi Fora, Kenya, said Leaky, who is based at New York's Stony Brook University.
Whether the two individuals passed by the eastern side of Lake Turkana at the same time – or a day or two apart – they likely knew of each other’s existence, said study co-author Kevin Hatala, a paleoanthropologist at Chatham University in Pittsburgh.
“They probably saw each other, probably knew each other was there and probably influenced each other in some way,” he said.
Scientists were able to distinguish between the two species because of the shape of the footprints, which holds clues to the anatomy of the foot and how it’s being used.
H. erectus appeared to be walking similar to how modern humans walk – striking the ground heel first, then rolling weight over the ball of the foot and toes and pushing off again.
The other species, which was also walking upright, was moving “in a different way from anything else we’ve seen before, anywhere else,” said co-author Erin Marie Williams-Hatala, a human evolutionary anatomist at Chatham.
Among other details, the footprints suggest more mobility in their big toe, compared to H. erectus or modern humans, said Hatala.
Our common primate ancestors probably had hands and feet adapted for grasping branches, but over time the feet of human ancestors evolved to enable walking upright, researchers say.
The new study adds to a growing body of research that implies this transformation to bipedalism – walking on two feet — didn’t happen at a single moment, in a single way.
Rather, there may have been a variety of ways that early humans learned to walk, run, stumble and slide on prehistoric muddy slopes.
“It turns out, there are different gait mechanics – different ways of being bipedal,” said Harcourt-Smith.
The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Science and Educational Media Group. The AP is solely responsible for all content.
Scientists study fossil footprints for clues about co-existing species of early human ancestors at the excavation site on the eastern side of Lake Turkana in northern Kenya, in 2022. (Neil Thomas Roach via AP)
Scientists study fossil footprints for clues about co-existing species of early human ancestors at the excavation site on the eastern side of Lake Turkana in northern Kenya, in 2022. (Neil Thomas Roach via AP)
An aerial view shows a research team standing alongside the fossil footprint trackway at the excavation site on the eastern side of Lake Turkana in northern Kenya, 2022. (Louise Leakey via AP)
ARLINGTON, Texas (AP) — Drew Lock finally got a start at quarterback for the New York Giants, and helped them get their first lead in seven games.
Then his two turnovers led to touchdowns for the Dallas Cowboys.
“Take care of the ball, and it'd be a good game,” Lock said.
With Lock their third different starting QB over three games, a span in which Daniel Jones was benched and subsequently released before Tommy DeVito developed a sore throwing arm, the result was the same for the Giants on Thanksgiving Day. They lost 27-20 to become the NFL's first 10-loss team this season — and the first eliminated from playoff contention.
The seven-game losing streak is the longest for New York (2-10) since setting a franchise record with a nine-game skid while going 4-12 in 2019.
“I thought Drew did some good stuff, and then two big turnovers,” Giants coach Brian Daboll said. “Can't have those turnovers.”
The Giants also had 13 penalties for 98 yards.
Dallas went ahead to stay on linebacker DeMarvion Overshown's 23-yard interception return for a touchdown early in the second quarter.
After initially being chipped by Devin Singletary as the running back went out for a screen pass, Overshown lunged forward, raised his right arm and tipped the ball up to himself when Lock tried to make the pass.
Overshown also recovered when Lock fumbled while being sacked on the third play after halftime. That set up a 38-yard Cowboys drive for a touchdown that made it 20-10.
But the Giants hadn't led since a 29-20 win at Seattle on October 6 until a touchdown on their opening drive Thursday, a day after Lock found out he was likely going to be the starter on a short week when the Giants only had walkthrough practices.
Tyrone Tracy’s 1-yard TD run made it 7-3 on the play right after Lock converted third-and-6 with a 28-yard scramble. Lock’s run was initially ruled a touchdown before replay review showed that the ball hadn’t yet crossed the goal line when his foot kicked the pylon in the front corner of the end zone.
Lock finished with 57 yards rushing on four carries, including an 8-yard touchdown with 2:18 left. He was 21-of-32 passing for 178 yards and sacked six times.
“Upset when you lose, but, I mean, nothing but fun. You love football, love being able to come out here and play on Thanksgiving,” Lock said. “A couple of things we could have done better, but the last 24 hours, I won’t forget it. Awesome opportunity to come out here and play. Wish we could have gotten it done.”
After serving as the backup to Jones, Lock remained the Giants' No. 2 quarterback when they decided to make a change. Daboll went with fan favorite DeVito as the starter last Sunday against Tampa Bay.
DeVito was 21 of 31 for 189 yards in a 30-7 loss to the Buccaneers. He was sacked four times and missed one play in the fourth quarter after being hit hard after making a throw.
The 28-year-old Lock was a second-round draft pick by Denver in 2019. He started 21 of his 24 games over three seasons with the Broncos, going 8-13. He was 1-1 as the Seattle starter last season when Geno Smith was sidelined by a groin injury.
Daboll said there was nothing significantly wrong with DeVito, other than being sore and swollen, and that he probably could be ready for their next game at home Dec. 8 against New Orleans. The coach wasn't ready to say who he planned to start at quarterback then.
“We just got done playing here,” Daboll said. “We've got a few days where we’ll go back and watch this game.”
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New York Giants quarterback Drew Lock (2) celebrates after running back Tyrone Tracy Jr. (29) scored a touchdown against the Dallas Cowboys during the first half of an NFL football game in Arlington, Texas, Thursday, Nov. 28, 2024. (AP Photo/Tony Gutierrez)
New York Giants wide receiver Darius Slayton (86) is unable to catch a pass in front of Dallas Cowboys cornerback Josh Butler (31) during the first half of an NFL football game in Arlington, Texas, Thursday, Nov. 28, 2024. (AP Photo/Tony Gutierrez)
New York Giants wide receiver Ihmir Smith-Marsette (87) leaps over Dallas Cowboys' Damone Clark (18) and Brevyn Spann-Ford (89) on a punt return during the first half of an NFL football game in Arlington, Texas, Thursday, Nov. 28, 2024. (AP Photo/Tony Gutierrez)
Dallas Cowboys defensive end Carl Lawson (55) sacks New York Giants quarterback Drew Lock (2) during the first half of an NFL football game in Arlington, Texas, Thursday, Nov. 28, 2024. (AP Photo/Jerome Miron)
New York Giants quarterback Drew Lock (2) is sacked by Dallas Cowboys defensive end Carl Lawson (55) during the first half of an NFL football game in Arlington, Texas, Thursday, Nov. 28, 2024. (AP Photo/Tony Gutierrez)
New York Giants quarterback Drew Lock (2) throws against the Dallas Cowboys during the first half of an NFL football game in Arlington, Texas, Thursday, Nov. 28, 2024. (AP Photo/Jerome Miron)
New York Giants quarterback Drew Lock (2) is sacked by Dallas Cowboys safety Donovan Wilson (6) and linebacker Micah Parsons (11) during the first half of an NFL football game in Arlington, Texas, Thursday, Nov. 28, 2024. (AP Photo/Tony Gutierrez)