新研究顯示，全世界最有名的黑白動物看得見色彩。這份刊登在《學習與行為》心理學期刊的報告，是由喬治亞科技研究院與亞特蘭大動物園的研究人員所發表。研究人員凱琳（Angela Kelling）測試亞特蘭大動物園的兩隻熊貓洋洋和倫倫，看看牠們是否能分辨顏色，結果發現，兩隻熊貓都能辨別顏色以及不同深度的灰色。
凱琳表示，「我的研究顯示大熊貓有某種程度的彩色視力。」凱琳目前是心理學院喬治亞科技中心研究保育行為的研究生，她說：「熊貓很有可能看得見兩種顏色，因為大部分食肉動物都是如此。」
對於熊類的視覺研究並不多，對熊貓的研究也是。凱琳表示，長久以來，人們以為熊的視力很差，也許是因為牠們的觸覺、嗅覺和聽覺非常好。
有些專家認為熊應該擁有某種色彩視覺能力，因為可以幫忙牠們分辨哪些食物可以食用，哪些不行，不過，幾乎沒有任何實驗證明這一點。不過有個針對黑熊的實驗，發現了熊可以分辨藍色和灰色，以及綠色和灰色之間的差異。凱琳就是用這份研究的設計為基礎，來測試亞特蘭大動物園的熊貓。
經過兩年時間，凱琳調查熊貓是否能分辨顏色和灰色的深淺度。在不同的測試中，將三個PVC透明管放在兩隻熊貓面前，兩個掛在一張灰階1/18的紙下，一個放顏色下，有紅色、綠色或藍色。如果熊貓推動有顏色下面的管子，就會得到獎賞；如果推兩個灰色管子中的任一個，就什麼也得不到。
凱琳分別測試每種顏色與灰階相比，在綠色和灰色這一組，熊貓挑選綠色的表現非常不一，但高於隨機值。在紅色對灰色這組，兩隻熊貓都比隨機值要高。在藍色的實驗，只有倫倫完成，而洋洋因為牙齒不太好，使得用食物誘使牠完成實驗的方式不太有效。倫倫在這個實驗中，去推藍色的次數只比隨機值低一次。
凱琳表示，「這項研究顯示大熊貓有某種程度的色彩視覺，但我們並不知道牠們看得見哪一種顏色，從研究中，我們不確定熊貓是否能分辨出個別顏色本身，例如可分辨藍色與紅色，或藍色與綠色的不同。」她補充說：「但我們發現到牠們能分辨東西是彩色或是灰色的。」
New research shows that the world's most famous black and white animal sees in color. The study, published in the psychology journal "Learning and Behavior," was completed by the researchers at the Georgia Institute of Technology and Zoo Atlanta.
Graduate researcher Angela Kelling tested the ability of two Zoo Atlanta pandas, Yang Yang and Lun Lun, to see color and found that both pandas were able to discriminate between colors and various shades of gray.
"My study shows that giant pandas have some sort of color vision," said Kelling, graduate student in Georgia Tech's Center for Conservation Behavior in the School of Psychology. "Most likely, their vision is dichromatic, since that seems to be the trend for carnivores."
Vision is not a well-studied aspect of bears, including the giant pandas. It has long been thought that bears have poor vision, perhaps, Kelling said, because they have such excellent senses of smell and hearing.
Some experts have thought that bears must have some sort of color vision as it would help them in identifying edible plants from the inedible ones, although there's been little experimental evidence of this. But one experiment on black bears found some evidence that bears could tell blue from gray and green from gray. Kelling used this study's design as the basis to test color vision in Zoo Atlanta's giant pandas.
Over a two-year period, Kelling investigated whether giant pandas can tell the difference between colors and shades of gray. In separate tests, the two pandas were presented with three PVC pipes, two hanging under a piece of paper that contained one of 18 shades of gray and one that contained a color - red, green or blue. If the panda pushed the pipe located under a color, it received a reward. If it pushed one of the pipes under the gray paper, it received nothing.
Kelling tested each color separately against gray. In the green versus gray tests, the bears' performance in choosing green was variable, but mostly above chance. In the red versus gray tests, both bears performed above chance every single time. Only Lun Lun completed the blue versus green tests because Yang Yang had a tooth problem that prevented him from eating the treats used as reinforcement. For this trial, Lun Lun performed below chance only once.
"While this study shows that giant pandas have some color vision, it wasn't conclusive as to what level of color vision they have," said Kelling. "From this study, we can't tell if the pandas can tell the difference between the colors themselves, like red from blue, or blue from green." "But we can see that they can determine if something is gray or colored," Kelling added.
