Nickolay Lamm
New animals have started to appear when two similar species have been forced into the same territory.
In 2006, a white bear with brown splotches, believed to be a hybrid of a polar bear and a grizzly, was shot by Arctic hunters. Hunters have killed three similar bears, sometimes called pizzly or grolar bears.
In 2009, a possible hybrid of a right whale and a bowhead was photographed in the Bering Sea.
In some cases hybrid animals are a response to a changing ecosystem. White-tailed deer populations have exploded on the East Coast of the U.S. and a new predator - the coywolf - has appeared that hunts them. It's a combination of Western coyotes and wolves, with some dog in the mix. Also known as the Eastern coyote, these canines are strong and social hunters like wolves, so packs can hunt deer; but they are also adaptable enough to live near humans, like coyotes.
In other cases, the increased hybridization of animals is a strong indication that our climate is changing. As Arctic sea ice continues to melt at drastic rates, different species of seals, whales, and bears previously blocked by huge slabs of ice will begin mingling in the same regions and possibly mating.
Hybrid animals are generally infertile, and the trend is worrisome because it could drive certain species to extinction since those animals are no longer mating with their own kind.
But genetic tests showed that at least one of the polar-grizzly hybrids was a second-generation animal, and the coywolf is a successful hybrid, which shows that some species might be resilient.
A study published in the journal Nature in 2010 listed 34 species that are at risk of cross-breeding because of a warming climate.
In the case of the coywolf we've used actual photos, but for the rest we asked artist Nickolay Lamm to help us imagine what some of those hybrid animals would like if they came to life.
Elin Pierce, a writer and editor with a Ph.D. in biology, helped to hypothesize what features the hybrid animals would have, based on dominant features of the original two species, and any descriptions or photos of those hybrids that already exist in the wild.