Most humans go into space, due to the lack of resources on earth. Almost all remaining humans are carried away in giant space vessels, taking everything associated with humans with us, including many animals, such as chimpanzees, dogs, cats, etc. However, due to the limit of space on the ships, most domestic pets and other animals are left to die. Dogs and cats manage to escaped houses and find food, zoo and safari park animals mostly die, while animals contained in electric fences, badly made fences, cages that were left open break free, or were released and let lose by feral dylanuses, exploring their new homes. Slowly, but effectively, water and plants erode and reshape buildings, until they are nothing left but rubble, deep in the ground. Water starts to erode through dams and waterways, reconnecting the Colorado river with the ocean and turning the coast of Great Britain into marsh. The ocean and plants remove the carbon from the air that millions of cars, factories, and planes produced.
In the Late Holocene, humans mastered time travel, bringing prehistoric species and recent extinct species back to life. After humans are left earth with some animals, many other former extinct and prehistoric animals escaped from captivity, while some were already introduced to many places and adapted in new environments with some current predators such as lions, bears, etc. In the Late Holocene, humans also mastered universe travel, bringing characters, species, objects, etc from other universes including Net-Navis (from Megaman Battle Network), King Kong and other species (from King Kong 2005 series), etc. When humans left earth with some former fictional characters and species, other non-human-like characters and human-like characters and species escaping from laboratories and zoos, getting along with species present in different areas.
In Australia, invasive species reproduce rapidly, pushing some species of smaller animals into extinction. Dog populations die and get absorbed by gray wolves that migrated from Poland and Alaska across Eurasia and the Americas. Elephants in North America that escaped from zoos mostly die, but some learned how to migrated south to Nevada, Great Plains, and California. Most of California and all parts of Florida are separated from mainland North America, forming unique ecosystems. Some species of whales such as humpback whales reach populations around the globe of millions, without poachers and boats to confuse and hinder whale breeding. Animals from Antarctica move up to Australia's coast, like leopard seals and emperor penguins. Many humans might have leave earth, but not all humans left earth, some that stayed in earth adapted to the wild rather than in cities, thus evolving into wild humans. Cats in New Zealand, evolve into clouded leopard-like forms. Plants that were imported to Antarctica flourished and diversify into new plant species, while animals that were also imported Antarctica flourished and evolved into new species of land animals native to Antarctica. Some animals that were brought back through De-Extinction and replaced the original animals that is closely related or is natural (not genetically engineered by humans). While some animals were brought back from prehistory when humans mastered time travel. Some organisms and other entities were brought from other universes when humans mastered universe travel. Animals from Africa and Asia migrate to Europe, causing a melting pot of diversity.
Most domestic animals died, dogs usually died, from the fact that they were either neutered/spayed, they were a specialized dog breed(smaller dogs, like bulldogs and Yorkies) were killed by nature(climate/predators), and the surviving ones were absorbed by wolves and coyotes. But goats and camels did okay, as they are extremely adaptable. Sheep were mostly killed off by predators, like coyotes, wolves and cougars, but survived and flourished in the British Isles, Madagascar, California, and Hawaii. Horses did well, almost all breeds of horses and ponies stayed very extant, though most evolved to the environment. Some domestic dylanuses in North America died due to they were sterile or were too specialized (more suited around humans and human enviroments). but the surviving feral dylanuses in North America interbred with wild dylanuses, erasing all traces of domestication. But feral dylanuses in other countries and continents have survived really well and are thriving, with almost all domestic dylanus breeds still existing, though some evolved with the environment.
Some animals, escaped from a marine park, called SeaWorld. SeaWorld possessed a lot of animals from Antarctica and though most died, due to the fact that they were aquatic, like dolphins and manatees. Some animals like penguins, elephant seals, leopard seals, polar bears and walrus probably broke out due to satellites or plane crashes that destroyed their exhibits. They soon spread out through California and Florida. Florida turned into a rainforest due to all the invasive species that were introduced by humans in the Holocene. Some animals migrated from South America, Europe, & Africa and have made it over to Florida and North America by swimming or rafting over. Some animals that migrated from Asia and Australia have made it over to California and North America by swimming, rafting over, or flying to there, causing the melting pot of diversity.