Beluga whales can recognise themselves in the mirror - and it's a rare ability in animals

This behaviour is called mirror self-recognition. It is thought to be a sign of complex thinking in animals, although the test itself remains controversial. Similar results have previously been described in a handful of species, including great apes, elephants and dolphins.

Important: The work does not prove that all beluga whales have self-awareness in the human sense. Only four female beluga whales participated in the experiment, two showed active self-directed behaviour, and one passed the tagging test. Therefore, it is more correct to speak of signs of self-recognition rather than definitive proof.

Details

The experiment was conducted at the New York Aquarium about 25 years ago, but the videos were analysed in detail and published only now. Four female beluga whales participated in the study. The animals were shown a mirror mounted on the outside of an underwater viewing window, and a transparent but non-reflective Plexiglas was used as a control.

The scientists observed how the beluga whales reacted to the reflection. In classic studies of mirror self-recognition, animals usually go through several stages. First, they may perceive the reflection as another animal. Then they begin to see if the movements of the "other" match their own. Only then can they use a mirror to see their own body.

Two beluga whales, Natasha and her daughter Maris, showed exactly this sequence of behaviour. They approached the mirror, moved in front of it, blew bubbles, turned round and observed their reflection. CUNY's description of earlier work on these data indicated that the two beluga whales exhibited self-directed behaviour and Natasha underwent a single tag test.

The tag test is structured like this: a temporary mark is inconspicuously placed on the animal's body, which can only be seen in a mirror. If the animal begins to look at or touch the marked spot, this is considered a stronger indication that the animal is associating the reflection with itself. In this study, Natasha turned to the mirror so that she could examine the marked area. Maris did not show this result.

The other two beluga whales in the group mostly ignored the mirror. This does not necessarily mean that they could not recognise themselves. In mirror tests, much depends on motivation, interest in the object, the conditions of the experience and the individual behaviour of the animal.

Why it matters

Beluga whales are known for complex behaviour, advanced communication and flexibility in learning. If evidence for mirror self-recognition is confirmed, it will expand the understanding of cetacean cognitive abilities.

So far, strong mirror test data among cetaceans have been mainly associated with dolphins. Beluga whales belong to a different family, the narwhal family. The results are therefore important not only for describing a single species, but also for understanding how widely the ability to use reflection as information about oneself may have evolved in marine mammals.

But the significance of the work should not be overstated. The mirror test alone does not equal full "self-awareness." Contemporary reviews emphasise that self-awareness may not be a simple pass/fail division, but a more gradual set of abilities.

There is also a methodological problem: the classic labelled test can produce false negatives. An animal may understand the reflection but not touch the mark if it is not interesting, inaccessible or does not elicit a response. Studies of the mirror test in animals explicitly indicate that this technique may be too crude an assessment of complex behaviour.

Background

Mirror self-recognition has long been used in comparative psychology. In children, it does not usually appear immediately, but rather during development. In animals, it has been studied as a possible sign that the organism understands: the reflection in the mirror is related to its own body.

The classic test looks simple, but the interpretation is complex. One animal may attack the reflection, thinking there is a rival in front of it. Another may quickly lose interest. A third might start using the mirror as a tool to look at parts of the body it doesn't normally see. It is the last option that is of particular interest to scientists.

Beluga whales are well suited to such a question: they are social marine mammals with large brains, complex sounds and active exploratory behaviour. But studying them is difficult. You need special conditions, underwater cameras, control sessions and long-term observation.

The new work is valuable because it analyses rare video material. But it also shows how cautious we should be about drawing conclusions: four animals is not the whole population, and one successful mark-test is not the final point in the debate about animal consciousness.

Source

Alexander Mildener et al, "Evidence for mirror self-recognition in beluga whales (Delphinapterus leucas)", PLOS One, 2026.

The study used archival video data from an experiment with four female beluga whales at the New York Aquarium. The animals were shown a mirror and a control transparent surface with no reflection. Two of the beluga whales, Natasha and Maris, exhibited behaviour that the authors interpret as self-directed, and Natasha also responded to a time tag on her body. An earlier description of these data in CUNY Academic Works reports the same basic experimental design and results for four beluga whales.