How do animals perceive their world in zoos and aquariums?

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Google Images

Time and Memory Processing in Animals

According to critics of marine parks, zoos and aquariums, captive animals (particularly dolphins, whales, elephants and primates) are utterly miserable creatures. The primary misery described by activists is that the animals are acutely self-aware, they miss the wild and their families, hate performing, feel like they are enslaved by humans, and hate being in cages and pools. They dream of freedom.


The various anti-zoo/aquarium groups make statements such as:

On captivity “…It is animal slavery…” 1

On animals performing: “…As you work, you are watched by hundreds of spectators. You are provided food as a reward for positive behavior, but if you behave against the guards’ wishes, you could possibly suffer the consequences of missing a meal. Your survival depends on care given by your prison guards. You don’t speak the same language as these guards, so you can’t tell them you don’t belong there…” 2

On living in an aquarium “…In nature, dolphins swim vast distances every day with their extended families, exploring new places and seeking out adventures and pursuits…” 3


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This dolphin was born at an aquarium. Dolphins don’t live with family members long-term. Check out Sarasota Dolphin Research Project

Dolphins, whales, elephants and great apes in particular are targeted by critics and activists as being uniquely special in the animal world. Projects on intelligence, self-awareness and emotions in these animals receive extensive popular press and has led to the public opinion that they are unusually smart. So smart that they shouldn’t be kept in zoos and aquariums.

It is true that dolphins, killer whales, primates and elephants are social animals with adaptive and flexible behavioral abilities, but does that mean that they are miserable in zoos and aquariums?




In one of my previous blog posts “Don’t Feed the Animals4 I explore a bit about animal motivation and how wild animals such as dolphins living in nature aren’t spending their time “going on adventures and exploring with their families”. That is a human desire and pleasure. All wild animals (yes that means dolphins and whales too) have one very important, all-encompassing, instinctual job to do; it’s to pass their genes to the next generation. To get to that ultimate end goal of passing on their genes (mating), an animal has to eat for energy and avoid death. To be successful at eating, mating and avoiding death, wild animals employ different life strategies and reside in specific ecological niches.

Wikipedia Google Images

Wikipedia Google Images

Some animals like dolphins live in oceans, feed on fish, live in groups and utilize flexible social behavior. Benefits of group life includes protection from predators, assistance with raising young and the ability to exploit different strategies for finding food. Disadvantages can include the need to spend valuable energy on group communication and understanding social order. This sounds like “fun” to a human, but in terms of energy consumption, it requires the animals to eat a lot and often.


Photo Credit: Irawan Subingar Google Images

Photo Credit: Irawan Subingar
Google Images

Other animals such as tigers live in forests, feed on large prey and live fairly inflexible solitary lives. Tigers don’t see the world the way a social animal does, and they have little concept of social behavior. Benefits of solitary life include large prey consumption all at one time, going days without needing to eat, and no food sharing. Without the need to spend valuable time understanding and maintaining social order, they get to sleep more. Communication is simplified to territory defense and mating. Disadvantages include not being able to adapt to sudden changes, loss of prey availability and habitat loss.

Too Much Time  On My Hands

the%20clockFrom prehistory through the present, one of the most all-encompassing things that dictates and controls human lives is time.

In the past, people had to plan and implement migrations, track prey availability and know when to plant seeds. In modern times, whether we are thinking of past experiences, planning for the future, watching the clock wishing it would go faster or slower, showing up to a meeting on-time or contemplating our inevitable death; an acute awareness of time dominates our lives. In fact, adult humans have a hard-time actually living in the present. Most of the time, we time travel to either real or imagined pasts or futures. We imagine ourselves making different decisions in the past and envisioning how those decisions could affect the future. We think about real decisions that were made and how they led to our present situations. We make plans for the future both short and very long term.

1282362_largeModern humans don’t spend much time engaged in basic day-to-day survival. With so much time on our hands in conjunction with education and information access, humans spend an excessive amount of time on mental time travel. This has helped advance our society, but it has also created a society full of worry, anxiety and stress.

There is so much stress from mentally time travelling, that multiple disciplines have been developed to help humans “live in the now”. Meditation, Zen, Mindfulness, Thoughtless Awareness, Flow and Yoga are but a few of the things that teach humans to live in and embrace the present. It has been shown that “living in the now” assists with a reduction of stress and helps with a richer appreciation of life. 5,6

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Google Images

Animals and Time

Animals have a sense of time, but it’s different from humans. Nature has provided them with an internal clock known as a circadian oscillator which keeps track of circadian cycles. Humans have some circadian rhythms too but not to the same extent as animals. These internal clocks are maintained by external cues such as temperature, day length, moon phases or celestial patterns which in turn cause changes to internal processes such as neural firing rates and hormone concentrations. Animal internal clocks ultimately dictate the timing for sleep, migration, reproduction, food storage, hibernation etc.7

Animals can also associate a particular time (based on the particular physiological state of their internal circadian oscillator) with food availability. If food is available at the same time each day, after some habituation, an animal’s internal clock will cue them to visit the same place at the same time to get the food. This is why animals appear to do certain things or go to certain places at given times of the day.

Google images

Google images

I’m sure many of you have a pet dog, and if you left the house for one minute or an entire day, the dogs seem equally ecstatic that you came back home. This has had many pet owners ask – Does my dog have any sense of time? A study by Rehn & Keeling (2011) took a look at that question and found that dogs were more excited to see their owner after 2 hours vs only 30 minutes, but there was no difference in the dogs response at the 2 or 4 hour mark. This meant that the dogs have some concept of elapsed time between 30 minutes and 2 hours, but not between 2 hours and 4 hours (and beyond).8

Time and Memory

Humans mix time and memory seamlessly, but is that the case with animals?

Human memory types9

Sensory memory – ultra-short-term buffer for stimuli received through the senses. A ticking clock is a good example of how we process sensory memory. We are aware and can hear the ticking, but typically the ticking is ignored unless we concentrate on it.

Short-term memory – used for a temporary (10 seconds up to 1 minute) recall of information which can be thought of as the brains “post-it-note.” Information held in short-term memory is not a complete concept and will disappear unless we make a conscious effort to keep it.

Long-term memory – intended for information storage over a long period of time and involves physical changes in the structure of neurons. Long-term memory can be divided into two main types: Declarative (knowing “what” such as facts) and Procedural (knowing “how” such as the unconscious memory of skills i.e. tying a shoe).

Declarative long-term memory is further divided: Semantic memory – structured record of facts, meanings, concepts and knowledge about the external world. Examples include types of food, capital cities, social customs, functions of objects etc. and Episodic memory – allows us to recall experiences and specific events in time in a serial form.

Kewalo Basin Laboratory Dolphin Research

Kewalo Basin Laboratory Dolphin Research

Animal memory

Animals from invertebrates to mammals have memory capabilities. Memory in animals is critical to help the individual species pass on their genes (identifying potential mates, avoid inbreeding) and learn and remember survival tactics (predator avoidance, finding food).

Animal working memory is a process where they learn about their environment and make appropriate adaptive response decisions.10   An example of working memory research includes delayed match-to-sample projects. Animals are presented with a stimulus (such as a specific shape like a triangle), and then that shape is removed. After some time, the animal is presented with multiple different shapes (square, circle) with the initial shape (triangle) among them. The animal is expected to remember that the triangle was the first shape shown and choose the triangle, not the circle or square. This is a very common experiment that demonstrates working memory.

Once an animal has learned the concept of match-to-sample, that concept (relationships between samples and correct choices) is stored in a reference memory. Reference memory contains the animal’s knowledge base regarding the relationships among stimuli, the outcome of stimulus-behavior combination, mapping relations between stimuli and behavior etc.11

Google Images

Google Images

Animals also have social memory capabilities known as social recognition.

Popular press makes it appear that dolphins are remarkable in their abilities for social recognition of each other12 however, the ability to learn and remember individuals is critical for the stability of all social groups.13 Amphibians to rodents and fish to social insects, animals use a variety of recognition mechanisms such as olfaction, visual, acoustic and pheromones to identify kin, neighbors, colony/group members and mates long-term.12,13,14,15,16,17,18

Beavers and hamsters use phenotype matching (such as visual or olfactory characteristics) to identify kin.19,20 Phenotype-matching mechanisms work when an individual learns its own phenotype, and those of its familiar kin. This information is stored in memory and later compared and matched to the phenotypes of unidentified animals. Beavers can even identify a sibling later in life by smell even if the sibling was removed at birth.

Remarkably, social recognition studies have found that wasps and damselfish use complex facial patterns to recognize individuals!21,22

22.Sheehan, M. J., & Tibbetts, E. A. (2011). Specialized face learning is associated with individual recognition in paper wasps. science, 334(6060), 1272-1275.

Sheehan, M. J., & Tibbetts, E. A. (2011). Specialized face learning is associated with individual recognition in paper wasps. science, 334(6060), 1272-1275.

This video shows the research where damselfish were trained to identify different faces!

Siebeck, U. E., Parker, A. N., Sprenger, D., Mäthger, L. M., & Wallis, G. (2010). A species of reef fish that uses ultraviolet patterns for covert face recognition. Current Biology, 20(5), 407-410.

However, whether it be a wasp, beaver or dolphin, just because an animal has the ability to recognize individuals does not mean they spend time thinking of or missing each other in the same way a human does when separated.

Funniest_Memes_remember-today-is-the-tomorrow-you-worried-about_13206Episodic Memory

A human’s ability to mentally time travel comes from episodic memory which enables us to reconstruct the actual events that took place at any given point in our lives. In particular, it is the memory of autobiographical events (times, places, associated emotions and other contextual knowledge) that can be communicated to others. We usually see ourselves as actors in these events, and the emotions associated with the event, not just the bare facts, are usually a critical part of the memory.23

Google Images

Google Images

Episodic Memory and Animals

Extensive research has been conducted with animals to see if they possess an episodic memory. Unlike other areas of animal behavior, this research has been very well-funded and many elegant peer-reviewed studies (with replicated studies) have been done. Some of the episodic animal research projects included having animals detect time of day, track short time intervals, remember the order of a sequence of events, and anticipate future events. Species studied have included pigeons, rats, monkeys, chimpanzees and even dolphins. Researchers in the field of human memory studies would find it advantageous to show that animals possess an episodic memory. That way rats, primates and other laboratory animals could be utilized to assist with finding cures and developing a better understanding of human memory diseases and conditions. However, overwhelmingly, time-and-time again, studies have failed to show that animals have an episodic memory. In fact, animals appear to be cognitively “stuck-in-time”.24, 25, 26, 27, 28, 29, 30, 31, 32

Stuck-in-time hypothesis

The results of the animal episodic research projects showed that animals cannot time-date events; therefore they don’t remember “when” events occurred. They also don’t anticipate future events. These findings led to the “Stuck-in-Time hypothesis which states that animals are essentially always living in the present.33

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Dolphin’s big brains are used for much more than living out human ideals. Check out my blog post “All about brains”

Wait! According to the internet dolphins remember past experiences and plan for the future!

There are actually very few published studies on dolphin memory. One paper, Mercado et. al (1999), is typically cited by researchers in the memory field. In that paper dolphins could not demonstrate episodic memory, only working memory functions.34 Other studies looked at dolphin future planning abilities with some interesting anecdotal accounts, but weren’t able to demonstrate episodic memory planning.35,36

Being “Stuck-in-Time” is the accepted scientific standard for animals in research, but there are a few who believe episodic memory, or perhaps an episodic-like memory, actually does exist in animals. Unfortunately studies to this regard are few, and the papers describing the concept mainly discuss philosophy, anecdotal accounts and theory.37,38,39

Google Images

Google Images

One formal study stands out as having the most potential for showing an episodic-like memory in animals. The study involves a bird called the Western scrub jay (the blue jay of the West) which is native to the Western part of the US. Part of the corvid family which includes crows and ravens, they are considered to be intelligent birds. The study was done by Clayton et. al (2001, 2003, 2009) where an experiment was designed that utilized the birds instinctual behavior for storing/burying food.40,41,42

The study received popular press, and Scientific American boldly stated this headline “It’s about Time: Animals remember past events in their lives”.43

Wow! Quite the declarative headline! The headline brings visions of animals contemplating their life history with human-like understanding.

Clayton, N. S., Griffiths, D. P., Emery, N. J., & Dickinson, A. (2001). Elements of episodic–like memory in animals. Philosophical Transactions of the Royal Society of London B: Biological Sciences, 356(1413), 1483-1491.

Clayton, N. S., Griffiths, D. P., Emery, N. J., & Dickinson, A. (2001). Elements of episodic–like memory in animals. Philosophical Transactions of the Royal Society of London B: Biological Sciences, 356(1413), 1483-1491.

For Clayton’s (2001) experiment39 she gave captive jays the chance to store their favorite food, worms, along with a less desired food, peanuts. She trained the birds to bury the food into ice cube trays filled with sand. The birds would bury worms and peanuts, and the tray would be removed. The birds would be given access to the tray after 4 hours, 24 hours and up to 5 days. (The worms began to rot after 24 hours and became inedible.) At first the birds dug up the worms every time they had access to the trays regardless of the time that had passed. However, over time, the birds only dug up the worms if it had been 4 hours or less since they had buried them. At the 24 hour mark and beyond, they didn’t dig up the rotted worms. Clayton argued that the fact that the jays understood that after a certain amount of time the worms were useless, they must possess a form of episodic memory.

Cool study, but does it conclusively show that animals mentally time travel or as Scientific American said “…Animals remember past events in their lives”? That’s a lot to infer from an experiment with a well-conditioned bird.

The work has been criticized by other researchers who suggest that the birds are using alternative memory methods (perhaps even some operant conditioning) in the experiment instead of episodic memory. To be episodic, the birds would have to understand “when” a food was buried and “how long ago it occurred”. Instead, the jays may be using a correlate of elapsed time (a keen circadian oscillator) to discriminate recent from more distant bouts of food storing.44

It’s about time….This lengthy post ended

So how do animals perceive time and memory while living in a zoo and aquarium?


Ask anyone who works with animals in zoos and aquariums and they will tell you that an animal perceives their world very differently from a human. That’s not a bad thing! Animals are remarkable in their own right; they have emotions and personalities, likes and dislikes, and their intelligence (I personally hate that word, it’s too ambiguous and too human) is uniquely suited to their ecological niche. Regardless, when you take a look at an animal’s natural history (how they live, reproduce and survive in their world) there is no reason for animals (in the wild or in captivity) to spend valuable energy emotionally mentally time traveling, longing for something in the past or hoping for something in the future. Not to mention that daydreaming animals would be eaten and fail to find a mate.

zen catUltimately, an animal is the ultimate Zen master, living life fully in the present. They assess and react to each situation for what it is, at that moment. Humans could take a lesson to that regard. So the next time you visit a zoo or aquarium or observe your pets, take a moment to live in the present and see if you can identify how the animals are doing the same.


Quiz Question: How does the picture below show potential episodic-like future planning behavior?

Photo Credit: Curt Hart

Photo Credit: Curt Hart


For an in-depth look at brains check out my previous blog “All About Brains


Literature Cited

  7. Roberts, W. A. (2002). Are animals stuck in time?. Psychological bulletin, 128(3), 473.
  8. Rehn, T., & Keeling, L. J. (2011). The effect of time left alone at home on dog welfare. Applied Animal Behaviour Science, 129(2), 129-135.
  10. Honig, W. K., & Thompson, R. K. (1982). Retrospective and prospective processing in animal working memory. Psychology of learning and motivation, 16, 239-283.
  11. Honig, W. K. (1978) Studies of working memory in the pigeon. In: Cognitive processes in animal behavior, ed. S. H. Hulse, H. Fowler & W. K. Honig, pp. 211-48. Hillsdale, N.J.: Lawrence Erlbaum Associates.
  12. Bruck, J. N. (2013). Decades-long social memory in bottlenose dolphins. Proceedings of the Royal Society of London B: Biological Sciences, 280(1768), 20131726.
  13. Kogan, J. H., Frankland, P. W., & Silva, A. J. (2000). Long-term memory underlying hippocampus-dependent social recognition in mice. Hippocampus, 10(1), 47-56.
  14. Mateo, J. M. (2004, January). Recognition systems and biological organization: the perception component of social recognition. In Annales Zoologici Fennici (pp. 729-745). Finnish Zoological and Botanical Publishing Board.
  15. McComb, K., Reby, D., Baker, L., Moss, C., & Sayialel, S. (2003). Long-distance communication of acoustic cues to social identity in African elephants. Animal Behaviour, 65(2), 317-329.
  16. Insley, S., Phillips, A. V., & Charrier, I. (2003). A review of social recognition in pinnipeds. Aquatic Mammals, 29(2), 181-201.
  17. Kogan, J. H., Frankland, P. W., & Silva, A. J. (2000). Long-term memory underlying hippocampus-dependent social recognition in mice. Hippocampus, 10(1), 47-56.
  18. Ferguson, J. N., Aldag, J. M., Insel, T. R., & Young, L. J. (2001). Oxytocin in the medial amygdala is essential for social recognition in the mouse. The Journal of Neuroscience, 21(20), 8278-8285.
  19. Heth, G., Todrank, J., & Johnston, R. E. (1998). Kin recognition in golden hamsters: evidence for phenotype matching. Animal Behaviour, 56(2), 409-417.
  20. Sun, L., & Müller-Schwarze, D. (1997). Sibling recognition in the beaver: a field test for phenotype matching. Animal Behaviour, 54(3), 493-502.
  21. Siebeck, U. E., Parker, A. N., Sprenger, D., Mäthger, L. M., & Wallis, G. (2010). A species of reef fish that uses ultraviolet patterns for covert face recognition. Current Biology, 20(5), 407-410.
  22. Sheehan, M. J., & Tibbetts, E. A. (2011). Specialized face learning is associated with individual recognition in paper wasps. science, 334(6060), 1272-1275.
  24. Roberts, W. A. (2002). Are animals stuck in time?. Psychological bulletin, 128(3), 473.
  25. Roberts, W. A., & Roberts, S. (2002). Two tests of the stuck-in-time hypothesis. The Journal of general psychology, 129(4), 415-429.
  26. Suddendorf, T., & Busby, J. (2003). Mental time travel in animals?. Trends in cognitive sciences, 7(9), 391-396.
  27. Suddendorf, T., & Corballis, M. C. (1997). Mental time travel and the evolution of the human mind. Genetic, social, and general psychology monographs, 123(2), 133-167.
  28. Hoerl, C. (2008). On being stuck in time. Phenomenology and the Cognitive Sciences, 7(4), 485-500.
  29. Tulving, E. 1983. Elements of episodic memory. Clarendon Press, Oxford, UK
  30. Bird, L.R., Roberts, W.A., Abroms, B., Kit, K.A., and Crupi, C. 2003. Spatial memory for food hidden by rats (Rattus norvegicus) on the radial maze: Studies of memory for where, what, and when. J. Comp. Psychol. 117: 176–187.
  31. Hampton, R.R., Hampstead, B.M., and Murray, E.A. 2005. Rhesus monkeys (Macaca mulatta) demonstrate robust memory for what and where, but not when, in an open-field test of memory. Learn. Motiv. (in press).
  32. Eacott, M. J., Easton, A., & Zinkivskay, A. (2005). Recollection in an episodic-like memory task in the rat. Learning & Memory, 12(3), 221-223.
  33. Roberts, W. A. (2002). Are animals stuck in time?. Psychological bulletin, 128(3), 473.
  34. Mercado III, E., Uyeyama, R. K., Pack, A. A., & Herman, L. M. (1999). Memory for action events in the bottlenosed dolphin. Animal Cognition, 2(1), 17-25.
  35. Kuczaj, I. I., Stan, A., Xitco Jr, M. J., & Gory, J. D. (2010). Can Dolphins Plan their Behavior?. International Journal of Comparative Psychology, 23(4).
  36. Miller, L. J., Solangi, M., Kuczaj, I. I., & Stan, A. (2010). Seasonal and diurnal patterns of behavior exhibited by Atlantic bottlenose dolphins (Tursiops truncatus) in the Mississippi Sound. Ethology, 116(12), 1127-1137.
  37. Eacott, M. J., & Easton, A. (2010). Episodic memory in animals: remembering which occasion. Neuropsychologia, 48(8), 2273-2280.
  38. Zentall, T. R., Clement, T. S., Bhatt, R. S., & Allen, J. (2001). Episodic-like memory in pigeons. Psychonomic Bulletin & Review, 8(4), 685-690.
  39. Dere, E., Kart-Teke, E., Huston, J. P., & Silva, M. D. S. (2006). The case for episodic memory in animals. Neuroscience & Biobehavioral Reviews, 30(8), 1206-1224.
  40. Clayton, N. S., Griffiths, D. P., Emery, N. J., & Dickinson, A. (2001). Elements of episodic–like memory in animals. Philosophical Transactions of the Royal Society of London B: Biological Sciences, 356(1413), 1483-1491.
  41. Clayton, N. S., Bussey, T. J., & Dickinson, A. (2003). Can animals recall the past and plan for the future?. Nature Reviews Neuroscience, 4(8), 685-691.
  42. Clayton, N. S., Russell, J., & Dickinson, A. (2009). Are animals stuck in time or are they chronesthetic creatures?. Topics in cognitive science, 1(1), 59-71.
  44. Roberts, W. A., & Roberts, S. (2002). Two tests of the stuck-in-time hypothesis. The Journal of general psychology, 129(4), 415-429.


3 thoughts on “How do animals perceive their world in zoos and aquariums?

  1. Thank you for a well presented and explained article highlighting this very important fundamental welfare and behaviour consideration. I enjoyed reading it very much and look forward to reading other articles in your collection.

    One minor correction, Nicky Clayton is a female scientist (at the Uni of Cambridge), you refer to her as a male which you might like to amend. She is married to fellow animal cognition scientist Nathan Emery who co-authors some of her research papers.

  2. Captivity also “deprives” them of the stress, predation, and starvation they would experience in “freedom”. Most animals live much longer in zoos than in the wild.

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