The Self-Awareness Capability in Giant Manta Rays

Contributed by Marielle Grenade-Willis

The capacity for self-awareness in marine species is not a newly discovered phenomenon. As Lori Marino divulges in “Cetaceans and Primates: Convergence in Intelligence and Self-Awareness“, the cetacean order has provided ample evidence of self-recognition, somatic awareness, and “goal-directed” behavior. However, its existence in fish is quite a novel idea, and the first study of its kind published in the Japan Ethological Society found that giant manta rays may possess self-awareness.

Mirror-self recognition tests (MSR) are used to detect whether an animal is aware of itself by exposing the animal to a mirror.  As Lauren Smith writes in The Guardian, “If they show social responses they likely perceived their mirror image as another individual and did not recognize themselves in the mirror. If they show repetitive and unusual movements they are considered potentially capable of passing the test. In the next phase researchers usually place a mark on the animal’s body (eg paint). They then observe what happens when the marked animal is placed in front of a mirror.”

Using a MSR test, two manta rays at the Atlantis Aquarium in the Bahamas were exposed to three different experiential conditions in a tank:

  1. A mirror placed in the water.
  2. The mirror was removed.
  3. A mirror-sized white board was placed in the water.

Although the traditional marking aspect of the MSR test was not used in this study, both manta rays “showed exploratory, contigency checking and self-directed behavior when exposed to the mirror”, suggesting that there was a level of self-awareness demonstrated by the species. Even more interesting is that both manta rays did not exhibit an increase in coloration change (which usually occurs when a new individual enters their territory or during socialization), leading the researchers to hypothesize that the manta rays were aware that the face staring back at them was in fact theirs.

There have been some criticisms of the MSR test as a suitable measure for self-awareness in fish species because as Business Insider’s Sean Kane puts it, “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.” As the prototype of self-awareness study in fish, this type of research still has a long way to go in becoming more applicable to the specific species being studied, but this is definitely a swim in the right direction.