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If you follow Yorkshire Wildlife Park on Instagram (or any other zoo for that matter) then you’ll see hundreds of pictures of animals playing with stuff. Polar bears with traffic cones, tigers opening birthday presents, lemurs eating ice cubes. You name it and a zoo has probably done it and put it on social media.

However, this isn’t just a gimmick to get more followers, this is a really important part of zookeeping called animal enrichment.

What is animal enrichment?

This sounds like a simple question so I’ll try and give a simple answer. Animal Enrichment is the act of making an animal’s life rich and interesting by providing lots of different stimuli.

To give a more full and precise definition (and you know how much I like definitions from my last blog post) I need to introduce a concept called the ‘five freedoms’. The five freedoms are the minimum requirements we should allow for keeping animals in captivity. They are:

  1. Freedom from hunger and thirst
  2. Freedom from discomfort (or the provision of adequate shelter)
  3. Freedom from disease and injury
  4. Freedom to express normal behaviour
  5. Freedom from fear and distress.

Think of these as the rules you have to meet to keep any captive animal keeping whether you are talking about a farm, pet shop, zoo or even your family pooch.

Animal enrichment is anything which we do to improve an animals life over and above just meeting the five freedoms.

Why should we provide animal enrichment?

Again this feels like an easy question with a simple answer like ‘to make an animal’s life better’. However, you should have learnt by now that I like to go one step further than the easy answer. What do we mean by making an animal’s life better? How do we measure that? How do we even know if it’s working at all?

Zebras can tell us how they are feeling so we have to watch their behaviour closely.

Almost all the studies around animal enrichment focus on changes in behaviour. Zebras and Giraffes can’t talk to us to tell us whether they are having a good time and it isn’t possible to constantly monitor hormone levels of all the animals in a zoo. Behaviour, on the other hand, is easy to observe and easy to record. So when we try an answer the question of ‘why should we provide animal enrichment’ we should be looking for answers about behaviour.

Animal enrichment encourages species-specific behaviours

There is no doubt that life in a zoo is very different to life in the wild. For a start, captive animals always get all the food and water they need without really needing to work for it. They also never have to worry about being eaten! In a lot of ways captive life is much easier for animals than living in the wild and this is going to have an effect on their behaviour.

Let’s take an anteater as an example. This is an animal born with a really long tongue to get right into a termite nest. It isn’t possible for a zoo to supply hundreds of real nests so instead they provide ‘ant pellets’ as well as a mix of mashed up fruit and other soft treats. If this food is provided in a bowl in the enclosure then the anteater doesn’t get to use his long tongue.

If instead you do what Dudley zoo did and put some mealworms in the bottom of a long plastic bottle then all of a sudden you have a much more natural feeding behaviour.

Anteater feeding on mealworms out of a plastic bottle showing an example of food-based enrichment

It’s really important that when we bring animals into zoos we don’t change them. Zoos should be places where people can get up close with wild animals, not places where we show them less interesting versions of what they can see on TV. We use animal enrichment as a way of keeping the species-specific behaviours active.

When trying to replicate species-specific behaviour it’s easy to pick a few good examples (there are more dotted further down this post). However, on the whole its actually quite difficult to do. The main challenge is working out what behaviours the wild animals are actually doing. Following a troop of baboons through the savannah of eastern Africa to monitor their behaviours is time consuming and expensive. Similarly, it might not even be possible to track a tiger long enough to check how much of its day it spends climbing.

Tracking tigers in the wild for long enough to complete a full behaviour study isn’t always going to be pracical.

When we don’t have a specific behaviour we want to encourage, and when there isn’t good enough science to allow us to make an accurate guess, there is another good way we can measure our animal enrichment programme…

Animal enrichment reduces unwanted animal behaviours

It is a sad fact that animals in captivity aren’t always happy. There is a whole other blog post to be written on this but for now I’ll just say that it happens even in the best of zoos.

Perhaps the most obvious way in which unhappiness presents itself in zoo animals is through stereotypies. Stereotypies are loosely defined as repetitive movements without a clear purpose, like pacing or rocking. We can use animal enrichment to reduce stereotypies in zoo animals.

The good thing is that it actually works. If you provide lots of different types of enrichment, you can clearly see the stereotypies dropping away. This graph of research done in 2006 shows the amount of stereotypies reducing by half as a result of animal enrichment:

Enrichment can more than half the presentation of stereotypies. Source here.

You see, providing ice cubes for lemurs is actually good for their general well-being and it also looks good on the Insta. It’s a win-win.

Animal enrichment provides interest for visitors

While the animals are the stars of the show, we need to remember that the humans are also important. There is a good bit of research which shows that the more enrichment a zoo provides, the better the public will perceive that zoo. I’ve not seen the science but I think it is reasonable to assume that the better public perception, the longer visitors will stay in the zoo and the more frequently they will visit. A key cornerstone of zoos is giving people that opportunity to interact with wild animals. Animal enrichment allows for better engagement with the public leading to longer lasting connections with nature.

From a business point of view more visitors equates to more admission sales and longer visits means more discretionary spend. There is no doubt that Shedd Aquarium’s viral posts of a penguin walking round an empty art gallery will end up getting them more visitors. But this isn’t a bad or negative thing. Zoos need visitors to stay alive, to support conservation elsewhere and to run scientific studies in house.

There is a balance to be struck. Zoos need to be careful that the enrichment doesn’t tip over into harming the animals quality of life just in order to get a better engagement from the public. For example, large carnivores like to sleep for a large portion of the day. If we were to constantly provide animal enrichment we might start violating the ‘freedom to exhibit normal behaviour’. The public would love it though, they might even think a moving lion is happier than a sleeping lion. In my view we need to see public engagement as a great by-product, not as a purpose in and of itself.

Awake and roaring or…
fast asleep?

How to provide animal enrichment?

There is a fantastic charity called Wild Welfare which have a really good section on providing enrichment. There focus is mainly on designing enrichment schemes and I’ve slightly adapted to work in specific animal enrichment cases. To get the full picture click on that link – their website is well worth a read in its own right.

The animal enrichment formula is called the ‘What, Why, When approach’. It’s a really simple way of setting out the goals of a specific piece of enrichment.

The first thing to consider is what does the animal do in the wild? What is the behaviour you are trying to get it to replicate in captivity? You could also think what is the stereotypy I want to reduce?

Then think about why the animal performs that behaviour. Does it do it to get food like the anteater example above? Does it do it as part of its normal movement like a lemur swinging on branches? Does it do it whilst watching for predators i.e. meerkats on tall rock?

The final piece in the puzzle is when does the animal perform that behaviour? If the answer is all the time then you might need a permanent enrichment plan. If it’s when the animal is a certain age then that might allow you to be thinking ahead.

Once you have these questions clearly written out you can then get some zookeeper heads together and come up with lots of creative ways to meet the brief.

What: Wild meerkats have tunnel networks. Why: keep them safe and cool in the sun. When. All the time.
Answer: These meerkats in Yorkshire Wildlife Park can move between enclosures using underground tunnels.

The next step up from the ‘what, why, when approach’ is the ‘The S.P.I.D.E.R. Framework’. It was developed by Disney’s Animal Kingdom in 1998 and has been a cornerstone of all their enrichment programs ever since. The spider acronym breaks down to Setting goals, Planning, Implementation, Documentation, Evaluation, Re-adjustment. Full details can be found here http://www.animalenrichment.org/spider and it is well worth a read.

What are the different types of animal enrichment?

Animal enrichment broadly comes under five different categories: food-based, physical, sensory, social and cognitive. Within each category are a number of sub-categories and within each subcategory there are further levels of grouping. Who doesn’t love a good classification system?

Food-based animal enrichment

Food-based animal enrichment is probably the simplest type of enrichment. Not surprisingly it is also the most common. One of the best things about food-based enrichment is that all animals need to eat so you can guarantee participation.

The concept is that you change the way the animal feeds in order to make it a bit more of a challenge to get the food. There are two ways to do this, either you make the animal’s normal food hard to get or you give them a new type of food.

There are many ways to make the food a bit more of a challenge. You can scatter food around the enclosure, you can bury food, you can put the food on the roof of the animal house or you can suspend the food from ropes. I’ve seen great examples of putting a tigers lunch at the top of a massive wooden pole so the tiger had to climb – something it wouldn’t do without a prompt. Another good example is that if you hang a lemurs food from trees they are more likely to show off their ability to eat upside down – something very common in the wild but relatively uncommon in captivity.

Tigers at London Zoo using a feeding pole to demonstrate their amazing climbing prowess.

When it comes to providing unusual food the most common example is providing frozen food in the summer. This is always a hit with Instagram and with zoo visitors. A less Instagram friendly one is providing vultures with a carcass rather than pre-prepared meat. I imagine that might get just as many retweets but for all the wrong reasons.

Polar bears being giving a huge ice block full of tasty food.

Physical animal enrichment

Number two on the ‘most popular types of animal enrichment’ list is physical enrichment. This is a broad category which splits very neatly into two subgroups, physical habitat enrichment and physical object enrichment.

Physical habitat enrichment is all about providing an interesting home for the animals to live in. This can involve ropes and climbing frames for monkeys, huge lakes for polar bears and even tunnels between enclosures for meerkats. The aim is to try and better mimic the animal’s home in the wild in the hope this allows it to express more of its species-specific behaviour.

Ropes and frames may not look natural but they do provide an important source of enrichment

A lot of the changes will be permanent and so it is crucial to be thinking about physical habitat enrichment from the very first stages of enclosure design. There is a fantastic example of habitat enrichment in Smithsonian National Zoological Park where the Orangutan can walk above the crowds on walkways in the sky. This allows it to travel a vast distance in the same way it would have to travel in the rainforests of Borneo whilst being an awesome experience for visitors.

Orangutans on the O line at the National Zoo in Washington DC.
Credit: Jarek Tuszyński (Wikimedia)

Physical object enrichment is where you give an animal a new object to investigate. Some of the things we think of a rubbish can be amazing toys for animals. Giving sealions a rope to play with underwater or giving marmosets a paper bag can provide them with hours of enrichment. If you’ve ever driven your car through a monkey section of a safari park then it you’ll know the monkeys really, really like new objects. You are buying their enrichment with your wiper blades.

One of the difficulties with object based enrichment is that animals get bored of the objects. The stimulation comes from investigation so once an object is known, then it can be tossed aside. To keep physical object enrichment going over a long time period it is important to have a steady stream of interesting things.

Sensory animal enrichment

This is a much less easy-to-spot kind of enrichment but that doesn’t make it any less important. Physical enrichment is all about touch, food enrichment will cover off taste but what about sight, smell and sound? Sensory animal enrichment is stimulating an animal’s senses of sight, smell and sound.

To stimulate the sense of smell zookeepers could leave a trail of blood in a carnivores enclosure. It sounds gruesome but can help some species show wild-type tracking behaviours. Cats in particular get a lot of stimulation from smell though it doesn’t have to be blood. An object impregnated with catnip or nutmeg can send cats wild without running any hind of hygiene risk.

Sight can be stimulated accidently if the zoo design isn’t thought through properly. A study done on African ungulates showed that their behaviour was substantially different if they could see an African lion in the enclosure next door. In some zoos with research facilitates television has been used to provide enrichment. It turns out gorillas really enjoy watching other gorillas on screen.

Sound is subtle so you may not have noticed it. In a number of indoor animal houses there are often speakers playing bird call. As well as helping to mask the sound of visitors, these noises can help animals feel calmer. However, you need to make sure that you don’t accidently play an alarm call and set all the animals into a panic!

Social animal enrichment

Social animal enrichment is where you allow animals to interact with other animals or humans. The simplest way to do this is to give an animal a friend of the same species. In captivity tigers live longer when housed in pairs and flamingos are more likely to breed if a flock is over 50 birds. It doesn’t just have to be the same species though. Some of the best exhibits I’ve seen have been mixed-species exhibits. This is much more of a challenge for zoo keepers and zoo designers but (if done well) they can really improve the quality of life for all the animals.

You can see two species of animal here but this exhibit at Yorkshire Wildlife Park actually had more than 5 different large animals.

Another type of social animal enrichment could come from human interaction. This might be a daily training regime for exotic birds or simple a regular hygiene check. The point is that something out of the ordinary is happening for the animal which is stimulating a whole new part of its brain.

Cognitive animal enrichment

Our final category is cognitive animal enrichment or puzzles. This is all about trying to get the animal to think. It’s a bit of a crossover with some of the above types but it is useful to think about on its own.

The classic cognitive animal enrichment is the puzzle feeder. All sorts of animals can be given puzzle feeders where the animal has to work out which levers to push and pull before food is dispensed. Even when other food is freely available a number of animals would rather use puzzle feeders to ‘work’ for their food.

Does enrichment work?

I hope I’ve convinced you now that enrichment is not just a gimmick. There are bags of good science to suggest that it really does help promote species-specific behaviours and reduce stereotypies.

The next time you see something unusual in a zoo enclosure (or on a local zoos twitter post) try and work out what its purpose is. I find that knowing why these things are there adds a whole new layer to the zoo going experience. And don’t forget, a zookeeper will have put a lot of thought into an animals enrichment programme – it would be rude not to notice!

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