But these subspecies overlap along the Coast Mountains in western North America. The olive-backed thrush has greenish-brown feathers and lives farther inland. As its name implies, it has reddish feathers. One subspecies is the russet-backed thrush, which lives on the west coast of the United States and Canada. However, when they do encounter each other, they can still breed and produce fertile young. These are groups of animals from the same species that live in different areas. Over time, this species has split into subspecies. She looked to a songbird called the Swainson’s thrush. Delmore wanted to know how hybrids might behave differently than their parents. Hybrids can be different from their parents in many ways. Hybridization, Delmore concludes, is “actually a creative force.” Going their own way And that would increase - not decrease - the variety of life on Earth. Eventually, it could become its own species, like the golden-crowned manakin. Or maybe it can thrive in a different habitat. A hybrid might be able to eat a certain food that its parent species cannot. That’s why “hybridization was often viewed as a bad thing,” Delmore explains.īut hybridization sometimes can boost biodiversity. That would reduce the variety of species. If many hybrids were produced, the two parent species could merge into one. In the past, many scientists assumed that hybridization wasn’t good for biodiversity. Only a horse mating with a donkey can make another mule.īiodiversity is a measure of the number of species. Most of these are sterile: Two mules can’t make more mules. For example, mules are the hybrid offspring of horses and donkeys. That means they may be able to mate, but they won’t create offspring. These exotic species now may encounter and mate with the native animals. People may even set loose animals from other countries, accidentally or on purpose, into a new habitat. Or as cities expand, urban species may increasingly encounter rural ones. They might put two closely related species in the same enclosure at a zoo. People can unwittingly create opportunities for hybridization, too. Later, the two species bred with each other. Poachers had thinned out the populations of giant sable antelope and roan antelope. Scientists have seen this happen with two antelope species in southern Africa. She is a biologist at the Max Planck Institute for Evolutionary Biology in Plön, Germany. “You have to make the best out of the situation,” says Kira Delmore. When animals can’t find enough mates from their own species, they may select a mate from another species. As the climate warmed, the southern species moved north and mated with the other species. For instance, researchers have found hybrids of southern flying squirrels and northern flying squirrels. These animals may encounter other, similar species. When the climate changes, a species’ habitat can shift to a new area. Members of the two groups of animals have mated, producing hybrid bears. This happens with polar and grizzly bears. For instance, the territory of two similar types of animals may overlap. Maya Faccio Fabio Olmos Alfredo Barrera Wise to hybridize? And rodents’ mating habits may affect what their hybrid offspring can eat. Some hybrid fish appear more vulnerable to predators. Hybrid birds may take new migration routes, they found. Scientists are trying to understand how this process - called hybridization (HY-brih-dih-ZAY-shun) - plays out. And sometimes its behavior falls somewhere in between that of each parent. Sometimes it behaves more like one parent species than the other. Sometimes the hybrid is weaker than the parents, or doesn’t even survive. So what happens when the DNA of two animal groups mix in a hybrid? There are many possible outcomes. Hybrid offspring get more variety in the DNA they inherit. But DNA from different species or species groups will have more variations. If the parents are from the same species, their DNA is very similar. And they can end up with a mixture of the parents’ traits. When animals mate, their young get a mixture of the parents’ DNA. These guide what an animal looks like, how it behaves and the sounds it makes. The molecules of DNA in each of an animal’s cells hold instructions. But when they do, their offspring will be what are called hybrids. It’s the first-known case of a hybrid bird species in the Amazon, he says. Those females may have preferred mating with yellow-capped males rather than snow-capped or opal-crowned males.Įventually, those birds became separate enough from the two original species to be their own, distinct species: the golden-crowned manakin. This bright color made males more attractive to females. But in later generations, some birds grew yellow feathers. The offspring initially had crowns that were dull whitish-grey, Barrera-Guzmán suspects. Thousands of years ago, these two species of birds started mating with each other.
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