Serbian Lion Cubs

Kasper, right, a three-month-old white lion cub, plays with zookeeper Nadja Radovic's hair in the lion's enclosure at Belgrade Zoo, Serbia, Wednesday, March 18, 2009. The cub, an extremely rare subspecies of the African lion, was born December 9 in Belgrade Zoo. White lions are unique to the Timbavati area of South Africa and are not albinos but a genetic rarity.(AP Photo/Srdjan Ilic)

Octavian the Lion

Octavian, a lion relocated from a Romanian zoo takes in his new surroundings at Lions Rock big cat sanctuary near Bethlehem in South Africa March 14, 2009. Octavian is one of a group of seven lions relocated from Austrian and Romanian zoos by international animal rights foundation Four Paws (Vier Pfoten).REUTERS/Mike Hutchings (SOUTH AFRICA ANIMALS ENVIRONMENT SOCIETY)

Bornean Sun Bear Cubs

In this Monday, March 16, 2009 picture provided by the San Diego Zoo, Pagi, right, a female Bornean sun bear cub whose name means (AP Photo/San Diego Zoo, Tammy Spratt)

Mississippi Snow in March

A cardinal sits among the branches of a wisteria vine on the morning of Sunday, March 1, 2009 in Starkville, Miss., after snow fell during the night.(AP Photo/Mississippi State University, Jim Lytle)

Polar Bear Cubs

Two newborn polar bear cubs are seen with their mother Huggies on their first day out at the Ouwehands Zoo in Rhenen March 17, 2009. The polar bear twins were born December 14, 2008 .REUTERS/Michael Kooren (NETHERLANDS SOCIETY ANIMALS)

Mars

This NASA Hubble Space Telescope image shows Mars in 2005. The European Space Agency (ESA) on Friday named a Frenchman and a German who will join four Russians in an innovative 105-day isolation experiment to test whether humans can one day fly to Mars.(AFP/NASA-HO/File)

Giraffe

Giraffe sticks out his tongue at Dusit Zoo in Bangkok, Thailand, on Tuesday March 10, 2009.(AP Photo/Sakchai Lalit)

Four Moons of Saturn

An image of four moons of Saturn passing in front of their parent planet in seen this image taken by NASA's Hubble Space Telescope February 24, 2009 and released by NASA March 17, 2009. In this view, the giant orange moon Titan casts a large shadow onto Saturn's north polar hood. Below Titan, near the ring plane and to the left, is the moon Mimas, casting a much smaller shadow onto Saturn's equatorial cloud tops. Farther to the left, and off Saturn's disk, are the bright moons Dione and the fainter Enceladus. REUTERS/NASA, ESA, and the Hubble Heritage Team

Binary Star System

NASA Spitzer Space Telescope artist's conception shows a binary-star system, called HD 113766, where astronomers suspect a rocky Earth-like planet is forming around one of the stars. NASA is preparing to launch next month the Kepler spacecraft with a new space telescope that for the first time will be capable of detecting Earth-like planets outside our solar system, project managers said.(AFP/NASA/File)

Polar Bears at Ouwehands Zoo

One of the two newborn polar bear cubs is held by his mother Huggies, on their first day out at the Ouwehands Zoo in Rhenen March 17, 2009. The polar bear twins were born December 14, 2008.REUTERS/Michael Kooren (NETHERLANDS ANIMALS SOCIETY)

Colliding Galaxies

This image provided by NASA from the Spitzer space telescope shows a pair of colliding galaxies called NGC 6240 in a rare, short-lived phase of their evolution just before they merge into a single, larger galaxy. The prolonged, violent collision has drastically altered the appearance of both galaxies and created huge amounts of heat -- turning NGC 6240 into an 'infrared luminous' active galaxy. This image was created from combined data from the infrared array camera of NASA's Spitzer Space Telescope.(AP Photo/NASA/JPL )

Saturn and Moons

This image provided by NASA is a Hubble Space Telescope close-up view of Saturn's disk captures the transit of several moons across the face of the gas giant planet. The giant orange moon Titan (AP Photo/NASA)

Owl Butterfly

This photo released by the Las Vegas News Bureau, shows an Owl butterfly hanging on a plant at the Bellagio Las Vegas Conservatory & Botanical Gardens Thursday, March 12, 2009.(AP Photo/ Las Vegas News Bureau, Brian Jones)

Tiger meets Dolphin

In this photo provided by Six Flags Discovery Kingdom, Mavrick, a 14-month-old male Atlantic bottlenose dolphin, blows a mass of bubbles while checking out Akaasha, a six-month-old female Bengal tiger at Six Flags Discovery Kingdom in Vallejo, Calif. on Thursday, March 5, 2009. Park animal staff strolled by the dolphin exhibit as they escorted the tiger cubs on their daily walk around the park.(AP Photo/Six Flags Discovery Kingdom, Nancy Chan)

Alaskan Volcano Mount Redoubt ready to erupt

In a January 27, 2009 file photo provided by the Alaska Volcano Observatory/U.S.G.S. steam and gas rise from a large fumerole on the north flank of Mount Redoubt, a 10,197-foot volcano in the Chigmit Mountains, in Alaska. Geologists at the Alaska Volcano Observatory Sunday increased the official alert level on the volcano to orange, the stage just before eruption.(AP Photo/AVO,USGS)

Gerberas Flowers

Gerberas flowers are seen in a field for export at a plantation in LLano Grande, 37 miles (60 km) east of San Jose, March 10, 2009. Flower producers have seen their exports to the United States and Canada reduced by 50 percent in the current global economic crisis, according to a producer's cooperative. REUTERS/Juan Carlos Ulate (COSTA RICA ENVIRONMENT BUSINESS IMAGE OF THE DAY TOP PICTURE)

Alabama Snowstorm in March

An early March snowstorm dumped inches of snow across Alabama, including this red barn on the campus of Auburn University in Auburn, Ala., Sunday, March 1, 2009. The storm then moved into Georgia, causing plane cancellations and threatening the East coast.(AP Photo/Dave Martin)

Giant Pandas Chuang Chuang and Lin Hui Playing

This 2005 photo shows two giant pandas on loan from China, Chuang Chuang and Lin Hui, playing together in their enclosure at the Chiang Mai Zoo in northern Thailand. It has been reported that the zoo has again resorted to artificial insemination the pandas after pornography, low-carb diets and even a spell out in the cold failed to inspire the celibate pair.(AFP/File/Pornchai Kittiwongsakul)

Planetary Nebula NGC 2818

This image provided by the Hubble Space Telescope shows the striking details of the famed planetary nebula designated NGC 2818, which lies in the southern constellation of Pyxis (the Compass). The spectacular structure of the planetary nebula contains the outer layers of a star that were expelled into interstellar space. The glowing gaseous shrouds in the nebula were shed by the central star after it ran out of fuel to sustain the nuclear reactions in its core. NGC 2818 is often heralded as one of the Galaxy(AP Photo/NASA)

Bald Eagle in Flight

An eagle flys over the Des Moines river, Tuesday, Feb. 24, 2009, near downtown Des Moines, Iowa.(AP Photo/Charlie Neibergall)

Circular Star Tracks

A 45-minute time exposure made for circular star tracks is seen over this run-down barn along County Road A near Iron River, Wis., Sunday night, Feb. 15, 2009. During the time exposure, the barn was lit with a battery powered spotlight using a technique called light painting.(AP Photo/Nate Rendulich)

Giraffe

A giraffe at Sydney's Taronga Zoo in Australia sticks her tongue out to visitors during an early morning feeding session, Sunday, March 1, 2009. A program called 'Roar and Snore' allows visitors to stay overnight and see the animals in late evening and early morning walks where they can feed a giraffe or pat a seal during the behind-the-scene tours.(AP Photo/Mark Baker)

Orangutan

Orangutan is seen at Dusit zoo in Bangkok Tuesday, March 3, 2009.(AP Photo/Sakchai Lalit)

Red Panda Cub 'Pemba'

Pemba, a four-month-old red panda cub makes his first public appearance at Sydney's Taronga Zoo, Australia, Wednesday, March 4, 2009. Pemba is the 44th red panda cub bred in the zoo's international breeding program for the endangered species since 1977.(AP Photo/Mark Baker)

Lion Cub

A lion cub looks at visitors from its cage at a zoo near Fier city, about 110 km (69 miles) from capital Tirana, March 1, 2009.REUTERS/Arben Celi (ALBANIA)

Grant's Zebra

A Grant's zebra named Honoria, behind, stands with her newborn at the Park of Legends zoo in Lima, Tuesday, Feb. 10, 2009. The baby Grant's zebra was born on Jan. 26 and is Peru's fourth ever born in captivity as part of a preservation program. Grant's zebras are numerous throughout a very wide area in Africa south of the Sahara. The newborn will be named through a naming competition.(AP Photo/Martin Mejia)

Comet Lulin

This image provided by NASA shows the Comet Lulin as it was passing through the constellation Libra when Swift imaged it. This view merges the Swift data with a Digital Sky Survey image of the star field. While waiting for high-energy outbursts and cosmic explosions, NASA's Swift Gamma-ray Explorer satellite is monitoring Comet Lulin as it closes on Earth. For the first time, astronomers are seeing simultaneous ultraviolet and X-ray images of a comet. Data acquired by Swift's Ultraviolet/Optical Telescope (blue and green) and X-Ray Telescope data (red). While all the planets and most of the other objects in the solar system circle the sun counterclockwise, Lulin circles clockwise, said NASA astronomer Stephen Edberg. And thanks to an optical illusion, from Earth it appears as if the comet's tail is in the front as the comet approaches Earth and the sun.(AP Photo/NASA)

Parrots

Parrots are seen at a zoo in Nanjing, Jiangsu province March 1, 2009. REUTERS/China Daily

Baby Gorilla

In this photo provided by the San Francisco Zoo, an infant male gorilla is presented for the first time to the media, Thursday, Feb. 12, 2009 in San Francisco. The baby gorilla was born December 8, 2008 at the San Francisco Zoo and now weighs 11.3 pounds. The Zoo is hand-rearing the infant gorilla and surrogate training another female gorilla after the birth mother did not show interest in the newborn. The Zoo announced a global 'Name the Baby' contest, as well as an online gift registry for its newest arrival.(AP Photo/George Nikitin, San Francisco Zoo)

Wombat

This photo provided by the Chicago Zoological Society shows a southern-hairy-nosed wombat joey, believed to be a female, snuggled up next to its mother, 8-year-old Kambora, at the Chicago Zoological Society's Brookfield Zoo in Brookfield, Ill., Wednesday, Feb. 25, 2009. The not-yet-named baby was born July 8, 2008, however, zookeepers were only recently able to get a good look at the youngster because, like all marsupials, wombat joeys develop in the pouch following a gestation period of approximately 21 days. The joey now weighs about 4 1/2 pounds. Currently, Brookfield Zoo is one of only four zoos in North America to exhibit southern hairy-nosed wombats and is home to four individuals (half the North America population), including the joey's sire, Carver.(AP Photo/Chicago Zoological Society, Jim Schulz)

Syrian Brown Bear

A Syrian brown bear lays in the snow at the zoo in Servion, near Lausanne, Switzerland, Thursday, Feb. 26, 2009.

Siberian Tiger

Siberian Tiger Tinka, plays in the snow at the zoo in Servion near Lausanne, Switzerland, Thursday, Feb. 26, 2009.

Monarch Butterfly

A Monarch butterfly perches on a tree branch as another takes flight at the Monarch Butterfly Biosphere Reserve, near the town of Chincua, Mexico, Thursday, Feb. 26, 2009. The Monarchs are not endangered, but scientists say deforestation could threaten its existence.

German Horses

Three horses run side by side through a snow covered meadow near Wangen im Allgaeu, southern Germany, on a sunny Wednesday, Feb. 25, 2009.