Method Article

A Modified Mirror Test as a Visual Guide for the Self-awareness Trait in Wild Antarctica Penguins, Pygoscelis adeliae

DOI:

10.3791/65927

July 8th, 2025

In This Article

Summary

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A specially devised Modified Mirror Test has been used to find the traits of self-awareness in wild Adelie penguins. The experiment, conducted in different terrains of Antarctica during January-February 2020, is probably the first attempt to report the presence of these characteristics in penguins.

Abstract

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In this study, the self-awareness trait was tested in Adelie penguins living on a remote island in Antarctica. Four experimental paradigms were designed for the study to visualize the effect of a coordinated and networked social life on generating the self-awareness trait in Adelie penguins. The study, conducted in extremely cold, snow-covered, and difficult terrains of Antarctica during January-February 2020, reports the presence of traits of self-awareness in wild Adélie penguins in their natural habitat on Dog's Neck Ice Shelf and Svenner Island in East Antarctica.

The study is based on a close and careful watch on their daily movements, social activities, and overall lifestyle. Besides, it reports reactions and postures of penguins in response to their images in mirrors during four experimental paradigms-group-behavior test, modified mirror test (MMT), hidden-head test, and colored-bib test.

The paper argues that these experimental paradigms are probably the first attempt to find the presence of self-awareness traits in any penguin species. It is a pioneering attempt in conducting a set of cognitive experiments on the free-ranging individuals of a nonhuman species in their natural environment, without any prior familiarization, conditioning, or acclimatization of the experimental species. It is postulated that experimenting in a remote natural habitat, without any external superimposition, brings out the intrinsic qualities of an animal, in perfect equilibrium with its surroundings.

Future studies integrating the socio-ecology and cognitive ethology of penguins may provide further insights into whether the reported self-awareness traits have evolved due to the cooperative behavior of individual penguins with conspecific individuals throughout their colonial/social setups. It is based on the understanding that self-awareness is an essential social requirement for a cooperative lifestyle and lies at the aggregated level of social cognition.

Introduction

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Scientists have been studying the behavioral ethos of nonhumans for a long time. Amongst various traits of nonhumans, the peculiarities of self-awareness have also been studied, but in a few species only. The literature reveals that Gallup Jr1 was the first to conduct such studies in 1970. To examine whether the particular nonhuman individuals, chimpanzees, in his case, possessed the capacity of self-recognition, Gallup Jr1 devised a novel technique using a mirror. Based on the ability of chimpanzees to recognize themselves as individuals through their mirror images and he named this technique the "Mirror Test".

In his original experiments, Gallup Jr identified four chimpanzees and after 2 days of isolation prior to the test, exposed them individually for 8 h on each of the 2 study days to their reflected images in a mirror. Following another 8 days-approximately 80 h-of prolonged exposure to their reflected images in the mirror, all the four chimpanzees, when marked with a red dye on a part of their body, which they could not directly see, attempted to touch the red marks on their own bodies after seeing their reflections in the mirror. It was interpreted as clear evidence that the chimpanzees possess the self-awareness trait, as they seemed to identify the individuals bearing the red marks, in the mirrors as being themselves. With this experiment, Gallup Jr. was able to show that chimpanzees possess the capacity for self-recognition.

Over the years, self-recognition through mirror-images has been reported as an emergent phenomenon in several studies on nonhuman species, including, amongst others, the great apes, bottlenose dolphins, Asian elephants, and most recently, a fish species-the cleaner wrasse2. The comprehensiveness of Gallup's mirror test has, however, often been challenged, especially with respect to animals that rely on sensory modalities other than vision to perceive themselves and their environment3.

In birds, self-awareness has been investigated successfully using the mirror test in pigeons4, magpies5, and Indian house crows6. Using the mirror-image technique, Epstein and his colleagues4 investigated the self-awareness trait in three pigeons through their ability to locate a spot on each of their body, which they could not see directly, following independent exposure and habituation to a mirror for ~15 h over a 10 day training period. The study of literature reveals that in all investigations, every individual bird, however, had to undergo a variety of prior laboratory experiences, similar to that of Gallup Jr.'s chimpanzees, and they all acquired repertoires similar to those of the experimental chimpanzees. It must be noted, however, that the ability of birds to generally recognize themselves visually in a mirror remains equivocal, with jackdaws7 and carrion crows8,9 having failed the mirror mark test10.

Mirror tests are often conducted under highly artificial laboratory settings, without knowledge of how individuals will react toward their reflection in the wild11. More generally, should a failure to recognize oneself or fail the mirror test necessarily mean that a particular nonhuman lacks self-awareness or the capacity to become the object of one's own attention12,13.

There are a few definitions of self-awareness. Henley equates awareness with self-reports indicating that an observer "consciously see" a stimulus14,15. We have considered 'self-awareness' as the ability of the animal to be intrinsically conscious of its surrounding environment and processes—the "turning inward" aspect of the self and its recursiveness16.

Penguins are ancient flightless birds found mostly in the Southern hemisphere. They are one of the few species surviving on earth for over 60 million years, having outlived even the dinosaurs. Over time, penguins evolved a suite of morphological, physiological, and behavioral features that make them arguably the most uniquely specialized of all extant birds. These adaptations have allowed penguins to colonize some of the most extreme environments on Earth17.

Amongst 17 species of penguins found worldwide, only seven species inhabit the Antarctica and sub-Antarctic islands, and of these, the Adélie penguin, Pygoscelis adeliae, is the most abundant18,19. They are social birds, with remarkable adaptive features, which include feeding, swimming, nesting, and breeding colonially in discrete homogeneous groups, but only in the ice-sea zones. The extreme climate of Antarctica necessitates a high level of cooperative behavior amongst these penguins-an essential prerequisite for the development and maintenance of rookeries-areas where penguins, seals, and some other species of animals or birds live or breed.

A study of literature revealed that no study has been done on finding self-awareness characteristics in penguins in Antarctica. This could be because of the presence of penguin colonies in remote and isolated places in Antarctica, coupled with its extremely cold environment (near the coast, the summer temperature may vary from 30 C to +10 C)20, and difficult snow-covered terrain.

In this study, possibly the first of its kind on any penguin species, we examined the responses and reactions of wild Adélie penguins Pygoscelis adeliae, both individually and as a group, to their self-images, generated in a mirror during several field experiments. Our investigations led us to tentatively suggest that Adélie penguins have the self-awareness characteristic (intrinsic quality). We argue that this self-awareness trait in penguins may play a critical role during their various colonial activities and social interactions in which individuals of this avian species are typically engaged.

This study is pioneering in reporting the presence of self-awareness trait in a non-human species in a natural ecosystem, without any acclimatization or prior training of test species. It is also the first study on penguins in the difficult, snow-covered, and barren terrain of the Antarctica region having extremely low temperatures, 30 C to +10 C. Here, not only proper care was ensured in handling the highly sensitive species but the prescribed 'Code of Conduct' was also strictly followed21.

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Protocol

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We observed all the procedures and protocols prescribed by the ATCM Resolution 4 (2019) 21 and Annex II to the protocol on Environmental Protection to the Antarctic Treaty 22 during our research studies in Antarctica.

1. Preparation

  1. As the climate is extremely cold, acclimatize to these conditions and get accustomed to live and work in difficult and isolated terrains.
    NOTE: Our team acclimatized itself and was sufficiently trained for conducting research on this terrain.
  2. Identify appropriate sites for the study in the Antarctica region because contrary to the general belief that penguins are found across the entire Antarctica region, the groups of Penguins in real terms are found in a few limited places only.
  3. Become familiar with the study animals for conducting experiments on them in Antarctica. Attempt to remove fear and shyness in penguins and develop affectionate bonding with them. To follow the example of this study, have a member of the group dress in the 'typical polar gear costume ' and kneel low to observe the natural responses of the penguins (Figure 1).
  4. For selection of study animals, keep a close watch on the movements, behavior, and living style of individual animals and on their daily life. For example, if they forage every day in the morning, plan to conduct the experiments at that time.

2. Experimental setup

  1. Select a plain patch of land on the rough terrain of the selected site in Antarctica for conducting experiments. Set up the experiment near the rookery where the nests of the penguins are located. (Figure 1).
  2. Large mirror open-air test to study the behavior of the penguins
    1.  Place a large mirror, having proper support, on the ground in the open air in the path of waddles of Adelie penguins and closely observe their reactions, both individually and as a group, to their mirror images. Take photographs for records and record the time of stay of penguins as individuals and in groups in front of the mirror (Figure 2). Keep the mirror in that position till the test penguins remain attracted to it.
      NOTE: The mirror should be large enough to be visible to penguins from a long distance and attract a reasonable number of penguins for the study.
  3. Modified mirror test
    ​NOTE: Contrary to literature reports on conducting the mirror test using a single mirror, we used two mirrors in the newly designed, modified mirror test to get a better idea of the penguins ' behavior by producing a 'reinforcing ' effect, which is not possible with a single mirror.
    1. Construct two three-sided, closed enclosures by fixing cardboard sheets with approximate dimensions of 75 cm x 100 cm and 75 cm x 50 cm firmly to the ground. Use the bigger enclosure for the main experiment and the small enclosure for closing the large enclosure or expanding the larger enclosure by 50 cm, as and when required (Figure 3).
    2. Prior to the main experiment, observe the behavior of penguins in the larger enclosure without mirrors, which is the control phase of the experiment.
    3. Place two glass mirrors, each 54 cm x 40 cm, as per the size of the larger enclosure, on the opposite sides of the larger enclosure to ensure that the penguins confront their mirror images within the enclosure. The use of two mirrors will produce a 'reinforcing ' effect on the penguins and will thus give a better picture of their behavior and mood (Figure 3).
    4. Observe their behavior closely and take photographs. Release the penguins immediately after conducting the study.
  4. Hidden-head test
    NOTE: The aim of this test was to determine the reactions of the penguins to their distracted/partly obstructed mirror images.
    1. Paste a circular paper disk of any color, 14 cm in diameter, on the front mirror in the larger enclosure at a height that is likely to obstruct the image of the head and upper body parts of the penguin.
      NOTE: Our disk was green.
    2. Record the period of stay of the penguins in the enclosure without and with the disk. Take photographs. Release the animals immediately after the study (Figure 4).
  5. Colored-bib test
    ​NOTE: Contrary to the previous experiment, the aim of this paradigm is to make the image colorful and see the reactions of the penguins to their new images. It will also ascertain the effect of external artifacts on their body and their reactions to their mirror images.
    1. Prepare some small, brightly colored bibs and fasten one bib around the neck of each of the six Adelie penguins, taking care to not allow the bib to obscure the contours of the penguin 's body. Observe their behavior in this attire carefully and take photographs; record the duration of stay of each penguin in the enclosure. Conduct the study without bib also. Release the animals when the experiment is complete (see Figure 5).

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Results

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Two sites were identified for this study of Adelie Penguins-Pygoscelis adeliae, the most abundant of all penguin species in Antarctica18 (Figure 1). The first was Dogs Neck Ice Shelf (S 70°03'43", E 24°51'58"), which was visited by the penguins frequently. The second was Svinner island in East Antarctica, bordering the sea (S 69°08'12", E 76°44'45"), which has a rookery of ~3,500 Adelie Penguins (Figure 1<...

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Discussion

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The main objective of this study was to determine the presence of self-awareness in wild penguins, Pygoscelis adeliae, in Antarctica, by studying the behavior of these polar animals after initial familiarization, in their natural environment and conducting a group-behavior test, a modified mirror test, a hidden-head test, and a colored-bib test.

Social behavior is an important aspect of the lifestyle of any species, and so is that of penguins. Therefore, we studied this aspect very ca...

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Disclosures

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The authors have no conflicts of interest to declare.

Acknowledgements

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The project was financially and logistically supported by the National Center for Polar and Ocean Research (NCPOR), Goa, India, and the Ministry of Earth Sciences (MoES), Government of India, New Delhi. The authors express their sincere gratitude to M. Ravichandran, Ex-Director, NCPOR, Goa, and Secretary, Ministry of Earth Sciences (MoES), India, for conceptual advancement of this study, and M. Javed Beg, Vikas Gandhi, Punarbasu Choudhury, Michelle Fernandes and Debdip Chakraborty for their help in designing the artifacts used in the field tests and in conducting the experiments. The authors would like to particularly acknowledge Captain Julius, a most capable helicopter pilot, for making a safe landing of the researchers possible on the rough and rocky terrain of Svenner Island in Antarctica. Special thanks to Dr. B. S. Aggarwal for meticulously editing the manuscript and providing suggestions to improve the manuscript.

This paper is dedicated to the fond memory of the late Prof. David W. H. Walton of the British Antarctic Survey, Cambridge, who had always been deeply interested in our studies.

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Materials

List of materials used in this article
NameCompanyCatalog NumberComments
Cardboard packing boxQuantity: 2
Looking glass mirrors-Large sizeQuantity: 1
Looking glass mirrors-Medium sizeQuantity: 2
Colored bibs of different colors (randomely selected)Quantity: 6
Iphone 11 or latest (to take photographs and for video recording) and photographic cameraQuantity: 2
Stop watch Quantity: 2
Polar dressQuantity: 1
Double sided tape Quantity: 1

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Tags

Mirror TestSelf Awareness TraitAdelie PenguinsCognitive ExperimentsSocial CognitionCooperative BehaviorVisual Self RecognitionGroup Behavior TestCognitive EthologyAntarctica Wildlife

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