A recent study suggests that manta rays may be self-aware as they reportedly waved at themselves and changed their behavior when in front of a mirror.
A TechInsider report said scientists from the University of South Florida in Tampa observed a pair of two giant oceanic manta rays and found them reacting to their reflections.
Instead of interacting with their mirror images as if they were another creature, the manta rays did a "contingency check." These involved blowing bubbles and waving their fins to see if the "other" ray does the same.
When the mirror was removed, the frequency of this behavior reportedly decreased.
USF's Dr. Csilla Ari, who received a grant from the Save Our Seas Foundation to study about cognitive and social behavior of rays, filmed the event which took place in Atlantis Aquarium in the Bahamas. Her report was recently published in the Journal of Ecology.
Ari said the responses implied the ability for self-awareness, similar to the proof seen in apes, as per a New Scientist report.
The researcher, who received the grant in 2011, also found out in a previous study that rays have the biggest brain among all fish.
However, the mirror test is not exactly the most credible way to test self-awareness.
In the same report by the New Scientist, the difference in behavior may actually be simply signs of curiosity. Gordon Gallup Jr. of the University of Albany, who developed the mirror test, said these studies are usually done only on a small sample of animals and cannot be reproduced.
He added that the more definitive proof of self-awareness is still in humans and great apes.
Also, the mirror test can only work in animals that use their vision for perception and cannot be replicated for creatures that cannot fully rely on sight, like bats, for instance. Therefore, there is a growing need to broaden the range of study on how animals can be recognized as self-aware.
Still, in the deep sea, dolphins are also known for their supposed self-awareness. Gallup's mirror test was also tested on them. It was found that they do not only recognize their appearance, but also notice changes in their looks.