The Sediments of Time My Lifelong Search for the Past

In the field of palaeoanthropology, one name keeps turning up: the Leakey dynasty. Since Louis Leakey's first excavations in 1926, three generations of this family have been involved in anthropological research in East Africa. In this captivating memoir, Meave, a second-generation Leakey, reflects on a lifetime of fieldwork and research and provides an inspirational blueprint for what women can achieve in science.

With The Sediments of Time, Meave* follows a family tradition. Her husband Richard, and his parents Louis and Mary have all been the subject of (auto)biographies, now many decades old. Science writer Virginia Morell later portrayed the whole family in her 1999 book Ancestral Passions. Much has happened in the meantime, and though this book portrays Meave's personal life, it heavily leans towards presenting her professional achievements, as well as scientific advances in the discipline at large. Thus, Meave's childhood and early youth are succinctly described in the first 15-page chapter as she is keen to get to 1965 when a 23-year-old Meave starts working with Louis in Kenya.

Whereas Louis and Mary were famous for their work in Olduvai Gorge in Tanzania, Richard and Meave have made their careers around Lake Turkana in northern Kenya. The first two parts of the book take the reader chronologically through the various excavation campaigns. These include the decade-long excavations in and around Koobi Fora, one highlight of which was the find of Nariokotome Boy (also known as Turkana Boy), a largely complete skeleton of a young Homo erectus. The subsequent campaign in Lothagam yielded little hominin material but did reveal a well-documented faunal turnover of herbivore browsers being replaced by grazers with time. Meave has also described several new hominin species. This includes Australopithecus anamensis, which would be ancestral to Australopithecus afarensis (represented by the famous Lucy skeleton), and Kenyanthropus platyops, which would be of the same age as Ardipithecus ramidus. That last name might sound familiar, because...

Having just reviewed Fossil Men, which portrayed the notorious palaeoanthropologist Tim White, I was curious to see what Meave had to say about him. In Fossil Men, Kermit Pattison already mentioned that she described White "with a note of sympathy" (p. 5), and she affirms that picture here, writing that he is "a meticulous scientist [...] intolerant of bad science [...] outspoken and frank [...] although he was charming and a gentleman in less formal situations" (p. 136). And though they meet more than once to compare fossils, notes, and ideas, they remain at loggerheads over certain claims.

Woven into Meave's narrative of exploration and excavation is an overview of how palaeoanthropology developed as a discipline, and what are some of its big outstanding questions. A recurrent theme is the influence of climate on evolution, often by impacting diet and available food sources. There is the difficult question of naming species and how much difference is enough to recognise a separate species, which ties into the whole lumpers vs. splitters debate in taxonomy. The latter readily name new species whereas the former (White being an example) point to sexual dimorphism and morphological variation and recognize only one or very few hominin species. Your stance in that debate affects what you think of Meave's descriptions of Au. anamensis as being part of a lineage towards Au. afarensis, and whether K. platyops is a species distinct from Ar. ramidus (White obviously thinks not).

This discussion of topics relevant to palaeoanthropology strongly comes to the fore in the book's third part, by which time Meave is examining the Homo lineage and the question where we appeared from. This sees her tackling topics such as human childbirth and the role of grandmothers, Lieberman's hypothesis of endurance running as a uniquely human strategy to run prey to exhaustion, palaeoclimatology and the mechanism of the Milankovitch cycles, the spread of Homo erectus around the globe (the Out of Africa I hypothesis), and the use of genetics to trace deep human ancestry. I feel that Meave overstretches herself a little bit in places here. Though her explanations are lucid and include some good illustrations, some relevant recent literature, on e.g. ancient DNA and Neanderthals is not mentioned.

Meave can draw on a deep pool of remarkable and amusing anecdotes that are put to good use to lighten up the text. And though the focus is on her professional achievements and the science, real life interrupts work on numerous occasions. Some of these are joyful, such as the birth of her daughters Louise and Samira. Some are a mixed blessing, such as Richard's career changes, first when Kenya's president hand-picks him to lead the Kenya Wildlife Service and combat rampant elephant poaching, then when he switches to attempting political reform. It removes him from palaeoanthropology and their time together in the field. Other occasions are outright harrowing, such as Richard's faltering kidneys that require transplantations, or the horrific plane crash that sees him ultimately lose both legs despite extended surgery.

Illustrator Patricia Wynne contributes some tasteful drawings to this book, though the figure legends do not always clarify the important details these images try to convey. And I would have loved to see some photos of important specimens, whether during excavation or after preparation, especially given how much Meave focuses on the scientific story in this book. Many specimens are described in great detail but the colour plate section mostly contains photos of the Leakeys and collaborators in the field. Another minor point of criticism is that I was not clear on Samira's part in writing this book. The dustjacket mentions her as a co-author, but the story is told exclusively through Meave's eyes, and the acknowledgements do not clarify Samira's role. I am left to surmise that Meave and Samira together drew on their store of memories for this book.

These minor criticisms notwithstanding, I found The Sediments of Time an inspiring memoir that provided a (for myself long-overdue) introduction to the Leakey dynasty. Meave has led a charmed existence and she is a fantastic role model for women in science.

* I normally refer to authors by their last name but, for obvious reasons and with all due respect, I will be deviating from that habit here and mention the various Leakeys by their first name.