SEATTLE — It's not that Peter Ward has a special fondness for rats. It's just that he sees them as survivors and, in the future world he posits, they might be the ultimate survivor — and evolver.
Sure, humans will still have their pets, but they probably will not thrive on their own and many will be genetically engineered. As for large mammals such as lions and tigers and bears, in Ward's world they will be driven to extinction by the loss of their habitats and global warming.
No, the real rulers will be rodents — and snakes. "The fossil record shows that they have the genetic capability of whipping out new species," says Ward, a biology professor at the University of Washington.
Oh yeah, cockroaches are also within the category he calls "champion speciators."
Ward is among the academics who focus on the future of evolution. Many agree that animal evolution will be shaped by urbanization, genetic engineering and climate change. But some disagree on whether humans themselves will continue as a species.
British geologist Dougal Dixon, in the book "The Future is Wild," creates a scenario millions of years from now in which humans become extinct and are replaced by an animal kingdom dominated by a giant land-based squid.
Why dabble in what Dixon himself calls "speculative biology?" For Dixon, it's a "novel approach to the instruction of science.
"To give fictitious examples of factual process and situations, especially in evolution, ecology and the other life sciences, gives people another way to look at those subjects — a way that has not been explored before," he says.
The future is now
In Ward's world, described in his book "Future Evolution," humans don't die off, but Earth as we know it sure has changed. "You've got to assume that humans are going to continue and at high population numbers," he tells MSNBC.com.
If that's the case, he says, then animals will have to evolve to thrive in two dominant environments — cities, where the masses live, and tracts of cropland cultivated to feed those masses.
Gone will be the vast grasslands that gave rise to large mammals. "I bet we'll never see a large animal species ever again," Ward says. "Give it a million years," he says, and lions, tigers and bears might all be gone.
More from TODAY.com
TODAY's Takeaway: Couple's 5 (new) babies visit, view from World Trade Center dazzles
On TODAY on Thursday, the anchors coo at five cute babies, Terry Shipman guns for Ellen's selfie record, and viewers take ...
- Chilling new viral video shows what war does to ordinary children
- Let them go! 'Frozen' musical parodies, tributes swirl across Web
- A hairy challenge: 428 employees shave heads for cancer charity
- Sorry, Pharrell. Music doesn't make everyone happy, study shows
- TODAY's Takeaway: Couple's 5 (new) babies visit, view from World Trade Center dazzles
Temperature swings over time in this world will favor species that can adapt relatively quickly, and animals will have to be able to survive in polluted air and water. A perfect world for rodents, snakes, cockroaches and foraging birds like crows.
Ward believes rats and snakes belong in the category known as "supertaxa," groups of organisms that create many new species while having a relatively low extinction rate.
Steve Stanley, a geobiologist at Johns Hopkins University who coined the term, agrees. Rats and snakes "are diversifying rapidly today," he says, "and if rodents continue to diversify, they will further stimulate the diversification of snakes, because many snakes eat rodents."
The human touch
A parallel track in this future world involves animals domesticated or engineered by humans.
Stanford biologist Stephen Palumbi, in his book "The Evolution Explosion," argues that humans have accelerated evolution with well-intentioned tinkering — and usually without thinking of the consequences.
He calls this tinkering "brute force evolution," writing that "we humans have a talent for upping the evolutionary ante and accelerating the evolutionary game, especially among the species that live with us most intimately — our diseases, food and pests."
"Anything that works we like to do more and more and more of," he said in an interview, noting that in the case of vaccines, insecticides and herbicides, that means short-term gains against disease and pests only to see them develop a resistance and come back even stronger.
Palumbi does see a "movement towards greater awareness" of such dangers and suggests that society take them into account much as it does significant environmental changes that come with development. "There's no reason we couldn't do an 'evolutionary impact statement,'" he says.
Do we really need a cat-dog?
Ward agrees with Palumbi's concerns, saying it's one thing to mix dog genes to come up with a new breed, but another to mix genes from different animals.
"If you really want to see how fast evolution can be," he says, "just focus on dogs." In just the last 200 years of human domestication, dogs "are now the most widely genetic type of creature on the planet."
But, he asks, "What happens if the same ease in producing things gets caught up in creatures we don't like?"
"We're attacking things with an ax and we don't yet have the sophistication" to know the impacts, Ward says. "There will be an escape of genomes from good stuff to bad stuff ... (and) it's going to effect evolution."
Earth without humans
In "The Future is Wild," Dixon, the British geologist, and co-author John Adams create an animal kingdom in which humans no longer reign.
Dixon and Adams give whimsical names to the creatures they dream up, aiming not so much to predict the future but to show some possibilities.
In their vision, humans become extinct in an Ice Age 5 million years from now. "Shagrats," or giant rodents, and "gannet whales," large aquatic birds, have evolved during this stretch of time.
The Ice Age melts away 100 million years later, marking the beginning of the end of large mammals and giving rise to creatures like the "ocean phantom," a jellyfish the size of a truck; the "swampus," a relative of the octopus that emerges from swamps to feed; and the "toraton," a reptile bigger than dinosaurs.
In 200 million years, evolution brings bizarre animals like "flish," birds that evolved from fish; "bumblebeetles," beetles that fly; and "megasquid," multi-ton, land-based squid creatures.
"Squibbons," a hybrid squid-gibbon ape, live in trees, eat plants as well as flish and "represent the pinnacle of intelligent life on Earth," according to Dixon and Adams' vision.
But it won't be the last species on top. "Undoubtedly," the authors conclude, "the far future will be even wilder."
Dixon says speculating about such a future helps educate people. "The public appetite for monsters and aliens and strange things of that sort can be a valuable tool and can deliver an audience that would be willing to be informed and educated," he says.
Ward isn't convinced and says his interest in the field of future evolution is driven by presenting scenarios that contrast with visions such as Dixon's.
'"I get tired of futurists so missing the mark, or so it seems to me," he says. "First, there is the sense that humans will soon be gone, or second, that we will produce some 'Blade Runner' world that is all pollution and Michael Jackson mouth masks."
Palumbi, the Stanford biologist, says that as long as humans do inhabit the planet it will pay to listen to Mother Nature. "Changes to the environment are irreversible," he said, "and thinking them through is important."
© 2013 msnbc.com Reprints