The bones they discovered within the sand have been a clue that one thing extra was buried beneath the floor. When a crew of excavators within the Turkana Basin, an archaeological web site in Kenya, dug deeper, they discovered extra proof that historic human ancestors had existed within the area: footprints.
“One lengthy path was tremendous apparent and actually spectacular,” mentioned Craig Feibel, a geographer at Rutgers University who was known as in to review the positioning.
Archaeologists had been in a position to decide that two totally different sorts of hominins, or residing beings that advanced after the break up from the apes 6 or 7 million years in the past, existed close to this historic lake in Kenya on the identical time primarily based on bones that had been found within the area. But these remarkably preserved footprints have been the primary to point that two totally different species of hominins — together with Homo erectus, which is a direct ancestor to people, and Paranthropus boisei, which was a distinct species that additionally descended from the ape ancestor however died off round 1 million years in the past. Both coexisted round 1.5 million years in the past on this area, Feibel mentioned.
In truth, the footprints point out these two species have been strolling alongside the lakeshore inside hours or days of one another, based on a examine revealed this week in Science that Feibel co-authored.
“You can by no means tie down the place bones come from [because] they might be transported or carried off by carnivores or scavengers,” Feibel instructed Salon in a telephone interview. “With the footprints, we all know these two species have been proper right here on the identical seaside inside a brief time period.”
A 3D computerized mannequin of the floor of the world close to Lake Turkana in Kenya exhibits fossil footprints of Paranthropus boisei (vertical footprints) with separate footprints of Homo erectus forming a perpendicular path. (Kevin Hatala/Chatham University)Over time, sediment accrued on the lakeshore and the footprints have been preserved underground. In the previous half 1,000,000 years, exercise within the Rift Valley has pushed up these layers of sediment with the footprints, exposing this fossil proof, Feibel mentioned.
“With the footprints, we all know these two species have been proper right here on the identical seaside inside a brief time period.”
In addition to those two species of hominins, researchers within the area have additionally discovered proof of ancestors of animals nonetheless present in Africa in the present day like giraffes, pigs, and elephants. The researchers on this examine additionally discovered giant footprints from a fowl, probably from the large marabou stork lineage, based on the examine.
“The lake margin is a extremely wealthy surroundings, so there would probably be aquatic sources like fish accessible there,” Feibel mentioned. “It would have additionally been close to an intensive grassland with numerous accessible plant sources and plenty of animals which can be utilizing these sources coming right down to the lake for water.”
Generally, our direct ancestors Homo erectus are thought to have used instruments and eaten meat, whereas P. boisei, an evolutionary cousin, had bigger jaws which can be thought to have been used to chew primarily vegetation. Both have been strolling on two toes, though that they had totally different gaits and foot shapes, which the analysis crew on this examine used to distinguish the footprints.
There’s no technique to know for certain what relationship these two species of hominins had with each other, however they probably coexisted as a result of that they had totally different diets and presumably habitat preferences, mentioned Matthew Sponheimer, an anthropologist on the University of Colorado Boulder.
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“If Homo erectus ate significantly extra animal meals than Paranthropus boisei, that alone would assure fairly totally different niches,” Sponheimer instructed Salon in a telephone interview. “We have little or no motive, given our present data of the diets of those species, to suppose there would have been a lot competitors.”
Footprints might help us higher perceive how numerous historic species moved about in a means that sedentary bones can’t, Sponheimer mentioned. In northern Tanzania, footprints helped anthropologists perceive that different hominin species additionally coexisted close to the well-known human ancestor “Lucy,” a species often known as Australopithecus afarensis, courting again roughly 3 million years in the past.
Footprints can even inform us extra in regards to the parts of the panorama that have been frequented by these hominins. For instance, there may be some debate about whether or not the massive jaws of P. boisei have been used to crack laborious meals like nuts or just chow down on crops. Discovering extra footprints within the area to get a greater thought of how this species was transferring across the lake may assist decide in the event that they ate principally crops or consumed different meals as properly.
“That our fossil ancestors and shut kin wanted water in itself will not be surprising … But among the finest methods to get ample energy given Paranthropus boisei’s chewing anatomy could be to eat crops close to water,” Sponheimer mentioned. “So it will be pretty if we had an unbiased line of proof that’s according to loads of this new dietary proof now we have.”
Researchers have been finding out this area for many years and proceed to seek out new fossil proof, Feibel mentioned. As these excavators proceed to seek for different historic remnants, they are going to probably be spending hours pacing alongside the identical shore the hominins earlier than them did 1.5 million years in the past.
“Footprints give extra element than these discrete bits of anatomy that we sometimes have,” Sponheimer mentioned. “And it simply hits you in another way visually whenever you see these footprints — simply as if you happen to have been strolling within the sand on the seaside.”
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