Diaries of a Speculative Biologist

The domestic canine or dog (Canis lupus familiaris) is one of the most widespread and populous mammal species on Earth, with approximately 400 million dogs across the world. They are a highly adaptable species, having established a number of feral populations globally. Some of the more notable feral dog groups include the dingoes of Australia, the singing dogs of New Guinea, the pariah dogs of Asia, and the Carolina dog of the southern United States. Although often dependent on humans for survival, feral canines have become adept to open and wild environments where they must hunt and care for themselves. Here are various concepts for descendants of the domestic dog.

Lupine pack-hunter

The most obvious possible future dog is one that fills the role of the domestic dog's ancestor, the wolf. Feral dogs and even domestic dogs (especially those raised for hunting, such as beagles) show many qualities of social predators, including the pyramid of dominance found in wolves. Thus, it is likely these large pack-hunters would live in groups (mostly related individuals in a pack) led by an dominant male-female pair. These dogs have the best chance to evolve in North America and in Great Britain where wolves are largely absent or are endangered. There would only be limited competition from solitary carnivores like foxes and cats.

Bone-crushing dog

In northern Europe, the British Isles, North America, and parts of Asia where there are no major land scavengers (like hyenas and jackals), there are a number of openings for dogs to evolve into hyena-like predator-scavengers. Such canines would most likely be huge, muscular beasts with short, robust jaws designed to crush bones and rip flesh. Such Cujo-like monsters could be either solitary or pack hunters; individuals in packs would likely have higher pup survival rates, longer lifespans, and greater chances of catching prey. Certain insular environments could also produce miniature bone-crushing dogs, having evolved to snap the necks of island fowl and other creatures.

The mesonychoid

Perhaps a more unusual dog descendant would be a canine adapted to a semiaquatic lifestyle. Such a species could evolve from breeds like the retrievers and Newfoundland dogs, known for their webbed feet and water-resistant coats. They could range from medium to large-sized mammals specializing in preying on birds and fish, as well as other aquatic fauna. Long maws would aid in capturing such prey items, while long, thick legs would allow them to wade through currents to reach areas where such animals are prevalent. Although there may be lots of competition from aquatic birds and mammals like otters and seals, eventually such dogs could evolve into short-legged swimming forms resembling the prehistoric Ambulocetus.

Chihuahuas from hell

One of the scarier ideas for future dog species is that of tiny, ferocious dogs that live in huge packs on isolated islands and forests. This concept resembles the modern bush dog (Speothos venaticus). They live in huge packs of at least a dozen individuals, which allows them to take down relatively large prey. It is possible that they also become burrowers, perhaps with a population branching out and becoming subterranean cave-dogs, hunting underground rodents and possible specialized armadillos. The concept of these toy-terrors is open to all sorts of fantastic and strange modifications.

*All of the above concepts are open to modification and reuse for future world and alternative world projects.

The domestic cat (Felis catus) is one of the most widespread mammal species thanks to the activities of mankind in the Holocene epoch. It has been introduced to every continent except Antarctica and has successfully established feral populations in many regions. Its effect on local wildlife has been drastic, surely shaping the ecosystems of future Earth. The cat itself will surely be shaped as well, and here are some possible descendants of the house-dwelling feline.

Apex predator

The cat is an adaptive predator and agile creature that could easily replace some of the top carnivore niches. In North America, it would certainly face competition from lynxes (or bobcats) and mountain lions, both adaptable and successful species. Still, they could easily outcompete both with their faster birthing rates and smaller bodies (both helpful in surviving extinctions). In Australia, there is also a good chance that the former house cats could become major predators. The local marsupial fauna could easily be pushed out of the way in favor of these placental predators. Cats and foxes would dominate the formerly marsupial-dominated environment. Such apex cats would likely be leopard-like or even lion-like predators (cats seem to be more social than some of their feline counterparts, possibly leading to a pride lifestyle).

Arboreal bird-catcher

Over the past few centuries, cats have made a major impact on the birdlife of the areas they've been introduced to. Perhaps this taste for avians could lead to specialization. The forest regions of North America and island chains such as the Galapagos and Hawaii would be perfect for species of cats adept to catching and preying on flighted birds. Cats have already shown to be skilled climbers and wild species, like the serval, are extremely capable of capturing birds while in flight. It is unlikely that such species would resemble the striger from After Man (as felines could not change their morphology so much as to be similar to a primate) and would also not evolve into gliding or flying forms.

Island monster

Islands seem like evolutionary machines, producing all sorts of unique creatures. Its likely that the descendants of domestic cats on islands would be far from their mainland counterparts, developing unique adaptations and specializations. With the process of island gigantism creating larger rodents and flightless birds on isles, the cats would be the best predators for such creatures. In fact, the descendants of cats could be instrumental in the development of anti-predatory defenses like sickle-claws on flightless birds (maybe even giant chickens!) or spines on giant isle rats. And of course such defenses would require adaptations on the part of the cats (a sort of biological cold war), perhaps leading to miniature versions of the prehistoric saber-toothed cats or even dropping cats (cats that are adapted to live in trees and drop down on top of large prey).

If you have suggestions for any more descendants, be sure to comment on this post.