Manta rays may be much smarter than their lumbering, undulating appearance suggests.
Two of the winged fish were observed waving at themselves in mirrors and behaving in ways that hint at self-awareness.
This revelation comes from an experiment by scientists at the University of South Florida in Tampa, who observed two giant oceanic manta rays (the largest species of ray) reacting to their own reflections.
The captive rays didn't interact with their reflected image as if it were another ray, and this behavior was not seen when the mirrors were removed or replaced with a blank white board.
Instead, the animals appeared to carry out what's known as "contingency checking" — watching the mirror as they moved their fins and blew bubbles, checking to see if the reflection matched their own actions.
The mirror self-recognition (MSR) test is a common test of higher intelligence and self-awareness, and only a small number of animals can do it.
Babies do it, of course, but the only non-human animals that have fulfilled the test are bonobos, orangutans, gorillas, Asian elephants, bottlenose dolphins, magpies, and chimpanzees, like this curious fellow:
Exciting! Fish are self-aware! Maybe? Not everyone believes the mirror test signals self-awareness in animals.
Some, including the designer of the MSR test, psychologist Gordon Gallup Jr., believe there's more to self-awareness to a mirror test, and that the new, non-ape results may be statistically insignificant and not reproducible.
"Humans, chimpanzees, and orangutans are the only species for which there is compelling, reproducible evidence for mirror self-recognition," Gallup told New Scientist.
Also, the mirror test is not the best measure of self-awareness for fish. It's not only biased towards well-sighted animals (manta rays don't have superb vision), but also favors creatures with nimble appendages. For example, a chimpanzee can recognize itself and easily pick at its teeth or poke a mirror while a fish can really only wave and blow bubbles in front of one.
So where does that leave us? More nuanced, fishier tests of self-awareness are needed to back up the claim.
