How Domestic Animals Succeed in the Wild
Animals such as chickens, cats, rabbits, donkeys, and horses not only establish large populations but often revert to the social behavior of their wild ancestors, despite being genetically very different.
NIGEL BARBER: ‘Many domestic animals can prosper in the wild despite having adapted to thousands of years in captivity. This phenomenon offers an interesting window into the process of adaptation to natural environments. Not all domesticated species do well when left to their own devices in a natural environment. Sheep often do poorly because they are vulnerable to predators. Yet in environments that lack large predators, they can do very well…
Other domestic species do much better in the wild—so well, in fact, that they wreak ecological havoc and cause the extinction of wild species. In the U.S., and elsewhere, feral cats kill large numbers of birds, for example. Apparently cats adjust easily to feral conditions because their hunting activities and reproductive behavior were little changed by the domestication experience.
They are not alone. Among domestic animals having large feral populations in the U.S are pigs, donkeys, horses, and anacondas formerly kept as pets. These populations are so large that they are considered an ecological problem or a source of damage to crops…
Biologists are beginning to ask how animals that were sometimes changed substantially by domestication could adjust so rapidly to life in the wild. This process offers clues into the adaptive mechanisms that affected their truly wild ancestors…
When domestic animals are released in the wild, those that succeed often acquire some features that are typical of the wild type… Feral animals sometimes converge with their wild ancestors in appearance. Examples include wild sheep developing larger horns (used in sexual competition), or pigs developing mottled coloration that aids camouflage.
Such changes have varied explanations. On their first exposure to natural environments, domestic animals may experience high predation rates resulting in intense and fast-acting natural selection. Feral animals often interbreed with wild animals so that they become hybrids…
Different though they might be, some domestic animals are capable of making a successful return to life without humans. In some cases, they act as invasive species that destroy both the habitat they occupy and out compete wild species pushing them to the verge of extinction.
Animals as diverse as chickens, cats, dingoes, rabbits, donkeys, and horses not only establish large populations but often revert to something closely resembling the social behavior, foraging activities, and anti-predator tactics of their wild ancestors, despite being genetically very different. Remarkably, these cases of successful re-adaptation to wild conditions take place in a small number of generations.
“Liberated” domestic animals often have high mortality so that natural selection can act quickly. Even so, the speed of adaptation seems too rapid for conventional gene selection to work, taking place in decades, or centuries, rather than the hundreds of thousands, or millions, of years over which conventional gene selection operates.
Adaptation probably takes place through more short-term behavioral change in response to altered environmental conditions. If so, behavioral change takes center stage in the drama of adaptation, and genetic evolution recedes into the background’. SOURCE…
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