Speculative biology (also known as speculative zoology) is a genre of science fiction that explores hypothetical scenarios in evolution. These works are often based on patterns seen in the natural world and history.
Dougal Dixon’s 1981 book After Man is widely credited with being the first work to use speculative biology in a major way. His book explores life on a world without humans.
The speculative biology subgenre of worldbuilding first appeared in science fiction literature with Dougal Dixon’s 1981 book After Man, which created a world with many different hypothetical species and described their interactions. Dixon’s work set the bar for other speculative biology books and influenced a number of movies that feature fictional prehistoric or future animals, including the 2005 film King Kong, which depicted Skull Island as a surviving fragment of ancient Gondwana populated by dinosaurs and other prehistoric creatures that evolved into their current forms thanks to the arid environment on the island.
Speculation about the origin of life has long been a popular scientific topic. Scientists once thought that microorganisms could spontaneously form from nonliving chemicals, but Pasteur’s experiments disproved this idea in 1865. In the years that followed, scientists favored a variety of other possible explanations for the formation of living things.
The concept of abiogenesis, or the process of forming simple living molecules that eventually become more complex and self-sustaining, is the basis for most modern ideas about the origin of life. This theory is often centered on the idea that a primordial Earth atmosphere contained reduced chemical compounds like methane, hydrogen, ammonia, water vapor and carbon dioxide, as well as reducing conditions such as low temperatures and high humidity.
A more advanced version of abiogenesis is the hypothesis that simple living molecules may have formed from nonliving material by a series of random events. These include chemical reactions, such as the breakdown of organic molecules and the formation of abiotic materials. It is also possible that the emergence of complex organisms may have been triggered by lightning strikes or ultraviolet radiation.
Speculation about the evolution of alien life is often more difficult than imagining the development of terrestrial organisms. This is because the laws of physics and the biological principles of ecology apply differently on other planets. Consequently, it is difficult to create convincingly realistic depictions of life on other worlds. However, this is not an impediment to a good deal of speculative biology, which has its roots in real-world science.
Speculative biology works often try to at least somewhat adhere to real-world scientific laws and are generally harder science fictions than, for example, science fiction in the fantasy genre. They can take inspiration from natural history, zoology or even art, but often they are designed to be more biologically plausible than, for instance, some works of science fiction that feature fictional animals. Artists specializing in speculative biology can find their audience online, on Deviantart or in fandoms that focus on animal characters, and some have also become well-known for their work in this field.
Among the most prominent examples of speculative biology are works that attempt to envision future evolution of animals and humans, as well as those that could exist on another planet or in the deep sea. One such work is Project Perditus, which takes place in the distant future where human civilization has expanded into other solar systems. It posits that a satellite has been sent to an analog planet that is similar in size and composition to Earth to assess the form that life on this new environment has taken millions of years after the arrival of humanity.
Other speculative biology works take an alternate approach to the future, often using fictional species that can be derived from natural history. For example, a popular scenario is what might have happened if non-avian dinosaurs had not gone extinct. Another common speculation focuses on what would happen if a particular event had been different in the past, such as a hypothetical flu pandemic.
Still others leave Earth and its history behind altogether, seeking to create and explore entirely alien biospheres. These can be on other planets, inside the atmospheres of gas giants or elsewhere in dimensions beyond our own. They may even explore the possibility of life on extraterrestrial moons or in the rings of these planets. This subgenre of speculative biology is often known as xenobiology.
The genre of speculative biology (sometimes referred to as “speculative zoology”) is best known for imagining creatures that might have existed in the past or on other worlds. It also explores what might happen in the future or on alternative timelines, a theme common to many other science fiction works.
In addition to these fantasy worlds, the genre also explores prehistoric creatures from a biological perspective. Speculative biology is often paired with xenobiology, which envisions the search for life on extraterrestrial planets, or astrobiology, which studies life beyond Earth.
Speculative biology is based on scientific research, but its subjects are invented rather than observed. This differs from a work of art, which relies on observation of real-world objects and events.
In the book King Kong (2005), geologist Dougal Dixon’s vision of Skull Island as a surviving fragment of Gondwana shaped the creation of prehistoric creatures on that island. His work influenced the designers of the rebooted King Kong movie, which featured a menagerie of nightmares, including giant lizards and flying fish.
A broader direction of speculative biology is future evolution, which considers what might happen to the biosphere in the near or distant future. This is similar to a science-fiction subgenre called alternate history, which explores what would have happened if a major event in Earth’s past had played out differently.
This genre includes works such as All Yesterdays (2012), a collaboration between zoologist Darren Naish, paleontologist John Conway and artist Mehmet Kozemen. This book presents hypothetical forms of existing prehistoric creatures based on a combination of speculative biology and paleoart.
A more familiar work of this genre is Cloverfield (2008), a film about a gigantic semi-aquatic monster that was designed with its habitat in mind. Other examples include the books After Man, Man After Man and The Future Is Wild. In this genre, the authors imagine evolution in the future on different worlds or in alternate timelines. They may also use genetic engineering and other technologies to create new creatures that would otherwise be impossible to produce in nature. Many of these works draw on a variety of sources for inspiration, such as science fiction, ancient mythology and natural history.
In this subgenre, artists use evolutionary principles to design fanciful but realistic creatures that could exist in the real world. This is a contrast to fantasy-based work, which aims to create fantastic creatures that break the laws of reality and biology.
Some of these artists delve into alternative evolution to explore what life might look like if certain events in Earth’s history had gone differently. For example, some works consider what the prehistoric landscape might look like if non-avian dinosaurs had not gone extinct and how other species might have evolved.
Other artists, such as Dougal Dixon, focus on the morphology of prehistoric creatures and what they might have been able to do. Dixon’s books, All Yesterdays (1981), The New Dinosaurs (Dixon 1988) and Man After Man (Dixon 1990), are cornerstone texts of the field, influencing many of today’s practitioners.
This subgenre also looks at the shapes that living creatures might take in alien biospheres, such as tidally locked planets or the atmospheres of gas giants and their moons. It might also examine how organisms might adapt to a changing climate, such as by developing a thicker coat or by breathing faster to counteract global warming.
Artists in this category are often inspired by the scientific method, using methods such as hypothesis testing and peer review to guide their work. In some cases, they even attempt to simulate the scientific process with an emphasis on the importance of measurable results. In other works, they employ linguistic tools such as “speculation keywords” to indicate hypotheses in the text. These are words and phrases, such as “it appears to be the case” or “it seems likely that”, that are often used in scientific writing as indicators of a proposed hypothesis. Speculation keywords are typically accompanied by a sentence or paragraph of context to explain why the hypothesis is being presented as an observation. This is a common technique in scientific abstracts, for instance, where a proposal to test a theory is surrounded by a summary of the existing scientific literature. This allows readers to assess the validity of the hypothesis without having access to the full scientific articles in which it may be buried.