The Top Human Evolution Discoveries of 2025, From the Intriguing Neanderthal Diet to the Oldest Western European Face Fossil

This has been quite the wild year in human evolution stories. Our relatives, living and extinct, got a lot of attention—from new developments in ape cognition to an expanded perspective of a big-toothed hominin cousin. A new view on a famous foot also revealed more about a lesser-known hominin species, Australopithecus deyiremeda. New tool and technology finds, coupled with dietary studies, showed us more than ever about the behavior of our ancestors and ourselves. New fossils gave us a glimpse at the earliest Europeans, predating both our own species and the Neanderthals. Finally, we dove deeper into the blockbuster story of the year, looking at some of the biggest Denisovan studies which give us a clearer than ever picture of these enigmatic human relatives.

Human traits of chimps and bonobos

A February study investigated theory of mind, or the uniquely human trait of recognizing the cognitive sapience of others, which allows modern humans to communicate and coordinate to an extent not seen in other animals. Study co-author Luke Townrow and colleagues set up an experiment where bonobos would receive a food reward hidden under cups, but only if they cooperated with their human partner and showed them where the food was first. Sometimes the bonobo could tell the human knew where the food was, and sometimes the animal could tell the human didn’t know where the food was. Bonobos pointed to the location of the hidden food more frequently and quicker when they knew the human was ignorant of the food’s location, indicating that they could interpret the human’s mental state and act accordingly, a hallmark of theory of mind.

In addition to cooperating, an April study shows that apes also share, especially when it comes to fermented fruit. Anna Bowland and colleagues documented the first recorded instance of fermented food sharing in chimpanzees, observed in Cantanhez National Park, Guinea-Bissau. At least 17 chimps of all ages shared fermented breadfruits, ranging between 0.01 percent and 0.61 percent alcohol by volume. While this may not be enough ethanol to result in the sort of intoxication levels desired by many humans, this demonstrates that food sharing, and fermented food consumption, have deep evolutionary roots, supported by the evolution of ethanol metabolism among all African apes.

On top of all that monkey business, an October study shows that chimps even have complex decision-making processes. Hanna Schleihauf and colleagues presented to chimps two boxes, one that contained food and one that was either empty or contained a non-food item. The chimps were allowed to choose a box twice, after receiving either weak or strong evidence about which box contains the food. The team found that chimps were able to revise their beliefs about the food’s location in response to more convincing evidence: When they picked the wrong box after the weak hint, they switched to the correct box after the following strong hint. Also, when they picked the correct box after a strong hint, they kept their selection after a weak hint. The study highlights the chimpanzees’ ability to make rational decisions, and even change decisions, in response to learning new information.

Fun fact: Chimps may use medicinal herbs

• In a study last year, researchers collected extracts of plants that they saw chimpanzees eating outside of their normal diets in Uganda’s Budongo Central Forest Reserve.

• The researchers discovered that “88 percent of the plant extracts inhibited bacterial growth, while 33 percent had anti-inflammatory properties.”

A holistic picture of Paranthropus

Besides learning more about our ape relatives, we also learned a lot more about some of our hominin cousins this year. Paranthropus is a genus of hominins consisting of three species, mostly known for their large teeth and massive chewing muscles that they likely used to break down tough plant fibers. However, not much was known about them outside of their mouths and skulls. A Paranthropus study from April helps to close this gap, describing an articulated lower limb from the Swartkrans site in South Africa. Travis Pickering and colleagues described a partial pelvis, femur and tibia of an adult Paranthropus robustus dating back 2.3 million to 1.7 million years ago. The anatomy of the hip, femur and knee indicate that this individual was fully bipedal. This hominin would probably have been only about three feet tall, one of the tiniest hominins on record. Due to a lack of other fossil material for comparison and the pelvis fossil being very incomplete, estimating the sex of this individual is more difficult.

However, another study from May pioneered the use of different methods to estimate the sex of Paranthropus fossils. Analyzing proteins preserved in fossil tooth enamel, Palesa Madupe and colleagues were able to determine sex and begin to investigate genetic variability in Paranthropus fossils from South Africa. Using these proteins, the team was able to identify two male and two female individuals, allowing for more accurate hypotheses about sexual dimorphism (sex-based body size and shape differences). The team also found that one of the individuals appeared to be more distantly related, hinting at microevolution within this species.

Lastly, a study published in October described a Paranthropus boisei hand from the Koobi Fora site in Kenya, which allowed scientists to learn if Paranthropus could have made stone tools. Carrie Mongle and colleagues looked at the nearly complete Paranthropus hand, which reveals a mostly hominin-looking morphology. Yet with strong musculature and wide bones, the grasping capabilities of Paranthropus seem to converge with that of gorillas, although they likely used this powerful grip to strip vegetation and process food rather than for climbing. Additionally, with a long thumb and precision grasping capabilities, the authors hypothesize that nothing in their hand morphology would have prevented Paranthropus boisei from making and using stone tools. This builds on other recent finds suggesting that the ability to make and use complex tools was not limited to the genus Homo.

The family of a famous foot

The Burtele foot, a fossil from Ethiopia that was described in 2012 and originally not given a species designation, dates to about 3.4 million years ago. Despite being contemporaneous with Australopithecus afarensis, Lucy’s species, the fossil looked almost nothing like it. The locomotor adaptations were completely different, and the foot still had an opposable big toe, like modern apes and the earlier genus Ardipithecus. In November, Yohannes Haile-Selassie and colleagues published research on other fossils from the same site where the Burtele foot was found. A new mandible with teeth links the hominin fossils at Burtele to a less well-known species, Australopithecus deyiremeda. This species had primitive teeth and grasping feet, with isotopic evidence pointing to a plant-based diet more similar to that of earlier species like Ardipithecus ramidus and Australopithecus anamensis. These new finds show that primitive traits persisted more recently into the timeline of human evolution and that our family tree is even bushier than previously thought.