Visions of prehistoric life require speculation. Ancient strata contain biological and geological clues to restore scenes from the deep past, but the task of the paleoartist is to arrange those scraps in an approximation of what life was really like. This requires as much imagination as science. Even the most exquisitely-preserved fossils can leave out details such as color, behavior, and the ecological role of the organism, all of which must be reconstructed according to an artist’s own particular style. As a result, paleoartists have often hewn as closely as possible to the probable form and habits of their long-dead subjects to uphold accuracy, but a new movement is seeking to push beyond traditional boundaries into the whimsically speculative.

Late last year, the collaborative team of John Conway, C.M. Kosemen, Darren Naish and Scott Harman published All Yesterdays: Unique and Speculative Views of Dinosaurs and Other Prehistoric Animals. The project’s aim was to imagine fossil creatures sleeping, playing, hiding, and otherwise engaging in activities different from the “prehistory red in tooth and claw treatment” so often seen in books, documentaries, and museum displays. Most striking of all was the second half of the book in which Conway and Kosemen applied trends in paleoart – such as skin wrapped too tightly on bones – to modern animals to underscore the point that dinosaurs and other ancient animals were probably far stranger than anything we’ve been able to conceive. Now, almost a year after All Yesterdays debuted, Kosemen, Conway, and Naish are back with All Your Yesterdays – an anthology of pieces from various artists inspired by unseen prehistoric possibilities.

View Images All Your Yesterdays, an anthology of speculative paleoart.

Because the book is a gallery created by disparate artists, All Your Yesterdays is more uneven than the original. Some of the illustrations – such as Alvaro Rozalen’s nocturnal rendition of the little dinosaur Epidexipteryx, Geunhong Pius Park’s plump version of the mosasaur Clidastes velox, and Rodrigo Vega’s snouty, swimming Spinosaurus – are just as stunning as anything in the original, but other entries are not quite as polished. All Your Yesterdays also runs a wider range of material between the scientifically speculative and the silly. Lew Lashmit contributed a fictional, oldschool vision of the long-clawed Therizinosaurus as a dinosaur that farmed for tubers, Mike Keesey turned the little-known prehistoric human from Denisova into an Abominable snowman, and Simon Roy envisioned a cyclops based on elephant bones, drawn from an actual connection between Greek mythology and fossils.

But such fanciful departures are relatively rare. With dinosaurs dominating the show, All Your Yesterdays purveys a slew of unique prehistoric vignettes that push behaviors seen among modern animals far back into the past. Vitaly Melnik’s shaggy pachycephalosaurs duel with speculative horns growing from their thickened skull domes, the pterosaur Dsungaripterus echoes the behavior of living bearded vultures in Andrew Dutt’s “Bones Away”, and Joschua Knuppe’s Heterodontosaurus defends itself with “a jet out foul-smelling feces.”

Filled with 180 pages of art and commentary, All Your Yesterdays presents a monumental amount of speculative artwork for fossil fans. That’s far more than I can do justice to here. But the book will certainly be a welcome addition to the library of anyone who grew up reading the speculative biology books of Dougal Dixon, such as After Man and The New Dinosaurs. And the traces of Dixon in All Your Yesterdays underscore the promise and pitfalls of the new paleoart movement.

View Images A speculative vision of Allosaurus with an inflatable sac on its head, as seen in All Your Yesterdays. Art by John Conway.

While Dixon had some startlingly imaginative ideas – remember the Night Stalker? – he often took traits and behaviors from living animals and attributed those features to his speculative beasts. The Lank was a pterosaur molded into the form of a giraffe, down to the body coloration, for example, and his Vortex was a penguin fashioned into a baleen whale. In a similar way, the “All Yesterdays movement” has projected behaviors and appearances specific to modern species onto prehistoric life. Beautifully-illustrated by Raven Amos, a pair of Gorgosaurus court just like modern bowerbirds, a feathery Jinfengopteryx envisioned by H. Esdaile uses a stick as a tool as a extant crow would, little alvarezsaurs pick at the flesh of the hadrosaur Saurolophus in an oxpecker tribute by Oscar Mendez, and Bethany Vargeson’s adorable Ambulocetus couple are an Eocene echo of sea otters.

All of the illustrations I just mentioned are beautifully executed, and none are inherently wrong, yet they speak to the limits of our imagination. In speculative paleontology, there is always a pull to take what’s peculiar about the modern and impress that specific biological point of interest into the past. Thus prehistory becomes modernized, and the unique nature of ancient life can become obscured. There’s also the opposite danger of making fossil creatures so unlike anything alive today that they might as well be monsters or aliens. Modern biology greatly informs what we know about the past, but I’m wary of taking specific coloration or habits and projecting the modern world onto a past we know relatively little about. There is a crucial difference in finding inspiration in modern biology and outright copying.

Nevertheless, the point of the All Yesterdays movement is to challenge our perceptions of how prehistoric animals lived. Imagination is essential to paleontology, and even discarding an idea or vision as unlikely or impossible brings us a little closer to unraveling the lives of animals we’ll never get to see in the flesh. At its best, such art can even raise prehistoric potentials that science may be able to discern. Perhaps future study of preserved sabercat DNA will be able to ascertain whether some were totally black, as Carlos de Miguel Chaves suggests in his piece, and a combination of fossils and evolutionary logic may eventually allow researchers to explore the possibility of Mike Keesey’s disturbingly cute mother Dimetrodon suckling her young. After all, some speculative paleoart – such as sparsely-feathered dinosaurs that started to poke their way into popular publications during the 1970s and 80s – has later been found to hold more than a small grain of truth. Art is one of the playgrounds the paleontologically-minded have to play with ideas and visions unseen, and for that reason I’m glad All Yesterdays has inspired artists to go beyond convention to show us possibilities of prehistoric life unlike any seen before.

All Your Yesterdays is available through Irregular Books as a free download (with the option to donate).