LEOPONS: Johnny, a leopon, is seen here in Kobe, Japan, circa 1960. Johnny is part lioness part leopard. Leopons typically have the head of a lion and the body of a leopard. Newscom
CAMAS: Dr. Lulu Skidmore, Principal Scientific Officer of the Camel Reproduction Center, holds a cama, known as Kamilah, in March 2002. Camas are a mix of llamas and camels. Kamran Jebreili/AP/FILE
WOLPHIN: A mix between a dolphin and a false killer whale is seen here in Sea Life Park in Hawaii in September 2005. Wolphins are a very rare hybrid. Mark Interrante/Flickr
ZORSES: Eclyse is a zorse, or zebroid, and is a hybrid of a female zebra and a male horse, seen here at a German safari park in July 2007. WENN.com/Newscom/FILE
TIGONS: One of two tigon cubs looks out of its cell at the Hainan Tropical Wildlife Park and Botanic Garden in Haikou, China, in October 2009. The cubs were born to a male Siberian tiger and a female African lion. Newscom/FILE
ZEDONKIES: A four-day-old cross between a zebra and a donkey is seen at Chestatee Wildlife Preserve in Lumpkin County, Ga., on July 26. Tom Reed/The Times/AP
LIGERS: Baby ligers are seen at a private zoo in Tainan, Taiwan, on Aug. 15. The zoo became the first in Taiwan to breed ligers, a cross between a lion and a tigress. The zoo keeper and owner may face fines for violating Taiwan's wildlife rules. Reuters
Polar and brown bears diverged between 4 million and 5 million years ago, but they continued to interbreed when the climate warmed, finds a new study led by the University at Buffalo and Penn State. Now, there is evidence that it is happening again.
Polar bears' past may echo their future, indicates a genetic study that finds the white-furred, sea ice-dwelling bears interbred with brown bears long after the two species separated as much as 5 million years ago.