Environmental enrichment: why it is important for zoo animals
環境エンリッチメント：なぜ動物園の動物にとって大切か
Georgia MASON Ph.D. Professor, Animal Sciences Department, University of Guelph
ジョージア ･ メイソン グエルフ大学 動物科学学部 教授
T h a n k y o u ve r y m u c h . S o , i t ʼmainly come from looking at stress and suffering ins a great pleasure to be here. Thispeople. So, we can look at humans having a terrible

afternoon, Iʼm going to cover four

day at work, and we can look at humans for whom themain topics. But, my ﬁrst topic is how

work stress never stops. We can look at people having

scientists assess stress and welfare in

an argument, or we can look at people trapped in aanimals. And this is important, if we

bad relationship. We can look at somebody crying. We

were to make decisions based on ourcan look at somebody whoʼs depressed. We can look atheads, and not just our hearts. Then Iʼm going to talksomebody whoʼs very frightened, and we can look at

about what captivity means for wild animals. Then Iʼmsomebody for whom the fear goes on and on. And ingoing to talk about what we know about the value of

people going through these states of bad welfare, we

environmental enrichment. And then Iʼm going to givecan measure many things that change in their bodies.

you some speculative information about what studies of

We can look at their hormones, we can look at theirlaboratory animals suggest might be mean functions of

immune systems and we can look at their behavior. And

environmental enrichment.

these measures give us measures to apply to animals.

䇼㪪㫃㫀㪻㪼㩷㪈䇽䇼㪪㫃㫀㪻㪼㩷㪊䇽䇼㪪㫃㫀㪻㪼㩷㪉䇽䇼㪪㫃㫀㪻㪼㩷㪋䇽So first of all, letʼs cover how people doing science

So what do we see? We typically see agitated, restlessassess animal welfare. And, the techniques people likebehavior. We see very strong desires to change theme use for accessing stress and suffering in animals

situation. People want to escape. We see depression,Workshop Ⅱ Zoo Improvement/Enrichment15

anxiety.
We see stress hormones being released, likeadrenaline and corticosteroids. We see problems withreproduction, infertility, infant death.
We see immune problems, and consequently we also
see high rates of disease, stomach ulcers, heart disease,and even shortened life spans.
So all these are measures we can look at in animals.
And I want just focus on two of these to explain them ina little more detail.
The ﬁrst is agitated restless behavior. So if a normal䇼㪪㫃㫀㪻㪼㩷㪌䇽

human being is stressed, we might see things like, youbite your nails, or you may pace, or you may move yourknee up and down in a restless way.
But if youʼre a human with a clinical condition like
autism or schizophrenia, then we see stereotypic
behavior which is very abnormal, very heavily repeatedbehavior. So on the left, we have a small boy with
autism who is waving his hands in a stereotypic way,
repeatedly.
And these are similar to what we see in very damaged
animals. So, here we see a monkey taken from its

䇼㪪㫃㫀㪻㪼㩷㪍䇽

mother very early, and again we see these very strange
behaviors when the animal is stressed. And anothermeasure I just want to explain in a bit more detail, is thestress hormones.
So these are adrenaline and corticosteroids.
Here we have the kidney, and above the kidney is alittle gland called the adrenal glands. And when we arefrightened, our brain sends a signal, and the adrenal
glands releases these hormones.
Okay, so now Iʼm going to spend a while talking
about what captivity means for wilds animals both, in䇼㪪㫃㫀㪻㪼㩷㪎䇽a good way and in a bad way. So, the important thing
to realize is that for a wild animal, captivity have someadvantages; itʼs safe, they have plenty of food. But, it
has disadvantages as well; it can be very boring andthe animals are physically restricted. So how do theseadvantages and these disadvantages balance out? Well,life in the wild is certainly very tough. Animals have tolook for water and food.
So this little bird here has to eat insects every few
minutes or it will starve, these deer are trying to findfood in the snow, these foxes are trying to ﬁnd water ina desert. Life is tough. And so for many animals, being

16

ワークショップ Ⅱ

動物園におけるエンリッチメントの実際䇼㪪㫃㫀㪻㪼㩷㪏䇽in, looked after by humans is wonderful.

unvarying behaviors, very similar to like what we see

They have food given to them, theyʼre safe, theyin people with autism. So here we can see two bears

have good health care. And this is true, not just forpacing. Hereʼs a jaguar pacing. And here this elephantis doing exactly the same movement each time, so it
puts its foot in exactly the same place each time it goes䇼㪪㫃㫀㪻㪼㩷㪐䇽䇼㪪㫃㫀㪻㪼㩷㪈㪈䇽䇼㪪㫃㫀㪻㪼㩷㪈㪇䇽domesticated species, but for some wild species as well.

䇼㪪㫃㫀㪻㪼㩷㪈㪉䇽So just to give you some examples of species that dovery well in captivity, grizzly bears do wonderfully inzoos.
They donʼt show abnormal, stereotypic behavior, they
breed very easily, and their infants survive very well. So
they seem very happy in captivity. And there are several
other species that seem very happy in captivity as well.
The Arabian oryx is one. The rhesus monkey isanother. The Ring-tailed Lemur does very in zoos, andso too does the Norway rat.
But we all know, sadly, that this is not the whole story.

䇼㪪㫃㫀㪻㪼㩷㪈㪊䇽And that for some animals in zoos, captivity really is around and round. So these behaviors are a problem.

problem, and we see bad behaviors like this stereotypic

And in some species, these stereotypic behaviors are

behavior in a bat.

very, very common. So for example, in giraﬀes in zoos,

So I want to talk now about some of the problems we

80% of the animals do stereotypic behavior.

see, and then maybe how we can solve them.

They do strange movements with their tongues;

So first of all some of the problems we see arethey stick them out, the move them round and round,

stereotypic behaviors which are these very repetitive,

they lick the wall, or they lick other objects in theirWorkshop Ⅱ Zoo Improvement/Enrichment17

enclosure. In other species, stereotypic behavior is also
common and we see other problems as well. So for
example, for both species of elephants in zoos, thereʼs many reasons to be concerned about their welfare.
Once again, they show stereotypic behavior, So thisagain, here we see swaying, and on the right we havethe video I showed you before. But we also see otherproblems as well in both species of elephants in zoos,
and weʼll hear about some solutions later this afternoon.
Across the elephants in zoos, we see veterinary
problems like lameness and skin diseases. Animals may䇼㪪㫃㫀㪻㪼㩷㪈㪋䇽kill their own babies, commit infanticide. Other animals
may be infertile and elephants often die prematurely.
So for Asian elephants in zoos, they live half as long as
they would if they were working in a timber camp, if
they were in their wild country.
Cheetahs are another species that often have problems
in zoos. So, one problem we see is that they produce
lots of stress hormones. If you look at stress hormonesthat are excreted, you see they have very high stresshormones compared to animals in the wild. And
because of this, their adrenal glands, the glands that

A :“:ˆ::»:…:w::A

produce the hormones, become very enlarged. If you
look at the adrenal glands from a cheetah in a zoo, they
are maybe four times bigger than the glands from acheetah in the wild. And because of these high levels ofstress hormones, they are very prone to problems with
their stomachs, gastritis and gastric ulcers. And on topof these problems, we also see reproductive problems
in zoos. So for example, when they breed their babies
are very at a risk of dying early and infant mortality
rates are twice of what you see in breeding centers in
Africa.
Itʼs not all bad news, however. So, how animals adapt

A :“:ˆ::»:…:w::A

to captivity, how they adapt to zoos is variable. It varies
across species, it varies according to whether it wascaptured from the wild or brought into a zoo, and it also
varies with what the zoo is like. So Iʼm going to give yousome examples and then show you how this can help
us identify solutions to welfare problems. So here is one
example of variation between zoos. So I told you that
infant mortality is high in this species, the cheetah, but
itʼs very variable between zoos. In some zoos itʼs quite
low, at just 17% in the ﬁrst six months. In other zoos itʼ
s very high with nearly half the infants dying before

18

ワークショップ Ⅱ

動物園におけるエンリッチメントの実際

A :“:ˆ::»:…:w::A䇼㪪㫃㫀㪻㪼㩷㪈㪏䇽䇼㪪㫃㫀㪻㪼㩷㪉㪉䇽

they are six months old. So some zoos are getting itright, some zoos are not. We also see variation between
species, with some species doing very well, and somespecies doing badly. So on this slide, the bottom row alltend to do well in captivity, and the top row tend to do
badly.
So these species donʼt show abnormal behavior, theirbabies survive well, the animals breed well, and theanimals typically donʼt have many health problems.
These related species tend to have health problems,䇼㪪㫃㫀㪻㪼㩷㪈㪐䇽abnormal behavior, and lots of other symptoms ofstress. So we can use scientifically, we can use thevariation between species and the variation between
zoos to objectively identify the origin of welfare
problems.
So here is one example. Across the species ofcarnivore we can see that lots of the variation in welfare
is caused by variation in their natural biology. So on thisgraph, each dot is a diﬀerent species. And here we havestereotypic behavior, how much abnormal behavior
they show, and here we see how big a home range they䇼㪪㫃㫀㪻㪼㩷㪉㪇䇽have in the wild. And this graph shows us that species
with small home ranges in the wild, like the mink andthe arctic fox, donʼt have much abnormal behavior inzoos, but species that have big home ranges in the wild,
like the polar bear and the lion have lots of stereotypic
behavior in zoos. And we see a similar eﬀect of natural
behavior as a risk factor for infant mortality in captivity.
So again, this is home range size in the wild, and here
is infant mortality in captivity, and again we can see
species that naturally have small home ranges do wellin captivity, species that naturally have big home ranges
tend to do bad in captivity. So the polar bear here: two䇼㪪㫃㫀㪻㪼㩷㪉㪈䇽

thirds of its babies will die in the ﬁrst month.

Workshop Ⅱ Zoo Improvement/Enrichment

19And if we look at the natural biology of a polar bear,
we can see what an enormous difference their life in
the wild is from their life in captivity. So when polar
bears in the arctic travel, a home range may be nearly
80,000 square kilometers, and even an animal witha small home range still moves a thousand square
kilometers each year. And this is a big contrast with thetypical enclosure size in the zoo, which may be just athousand meters squares. So the typical enclosure sizein the zoo is 1/1,000,000 the size of the home range inthe wild. We can see this is a big diﬀerence, and maybe䇼㪪㫃㫀㪻㪼㩷㪉㪊䇽no wonder thatʼs why they have welfare problems. So
this was an example of species diﬀering in welfare andﬁnding out the reasons why.
So you can see that we can use variation between zoos
to start identifying what causes animalsʼ bad welfare.
And here is one last example. So this species is theclouded leopard. And another multi-zoo study by Nadja
Wielebnowski showed that in zoos that have lots ofhiding places that are up high and lots of places where
the animals can escape from the public, again theseanimals have low levels of corticosteroids. But if there䇼㪪㫃㫀㪻㪼㩷㪉㪋䇽arenʼt places to hide, then the animals have high levelsof corticosteroids.
So put together this information showing that wide
ranging species tend to have more welfare problems
and that animals that canʼt retreat from humans tend
to have more welfare problems, really raises twoquestions. And the first question is: Do animals missa natural life? Is not having a natural life a problem?
And the second question is: Can we make bad welfare
conditions into good welfare conditions by making theenvironments more natural? And as professor Ueno䇼㪪㫃㫀㪻㪼㩷㪉㪌䇽

said, one signiﬁcant way of doing this is to add objects䇼㪪㫃㫀㪻㪼㩷㪉㪍䇽20

ワークショップ Ⅱ

動物園におけるエンリッチメントの実際

and structures to interact with in the environment; so toenrich the environments and to give the animals more
to do.

䇼㪪㫃㫀㪻㪼㩷㪊㪇䇽䇼㪪㫃㫀㪻㪼㩷㪉㪎䇽䇼㪪㫃㫀㪻㪼㩷㪊㪈䇽leopards and zoos that donʼt have hiding places seem tohave more stressed clouded leopards. So this suggests䇼㪪㫃㫀㪻㪼㩷㪉㪏䇽an obvious way of improving the enclosure for thisspecies: give them more hiding places. So does thiswork? So here is data from an experiment by Nadja
Wielebnowski from Brookfield Zoo. And here, eachpair of bars is one animal, so there were six clouded
leopard here. And what these data show is their levelsof stress hormones. The black bars show their stresshormones before they were given enrichments andthe white bars show their stress hormones after they
were given raised up places in which they could hide.
And you can see that in every one of the six clouded䇼㪪㫃㫀㪻㪼㩷㪉㪐䇽leopards in the six diﬀerent zoos, when they were given
hiding places, their stress hormone levels went down;

So what I want to do now is to show you sometheir stress hormone levels more than halved. So thatʼsdata that illustrates how important environmental

a nice example looking at stress hormones. What aboutenrichment is for animals in zoos. And Iʼm going toabnormal behavior?

give you examples from zoos, but also examples fromSo here we see the typical stereotypic behavior ofother species as well, just because theyʼve been soa gerbil kept in a laboratory cage. They go to thewell studied. So I showed you this slide just now, and I

corner of the cage, and they make these digging,told you that across diﬀerent zoos, zoos that have lots

digging, digging movements. So, why do gerbils showof hiding places tend to have more relaxed clouded

stereotypic digging? And, can we stop this behavior

Workshop Ⅱ Zoo Improvement/Enrichment21

If it can see other horses, it will show much less of
this behavior. And even if you give it a mirror, thatwill reduce its stereotypic behavior. So this isnʼt a realnatural stimulus, but it tricks the horse into thinking
that it has company. And the it feels as though it is in aherd. So this is a very nice example of an environmental
enrichment that is artiﬁcial, but it mimics an aspect of
the natural life.

䇼㪪㫃㫀㪻㪼㩷㪊㪉䇽A :“:ˆ: :»:…:w: : A

A :“:ˆ: :»:…:w: : Awith environmental enrichment? Well, if you look atwhat gerbils do in the wild, they live in the desert andthey naturally dig burrows. And here, you can just see
the little gerbil. Can you see its eye poking out of thehole? So they dig these burrows to escape from theheat of the desert sun and to hide from the cold of thedesert night. So having a burrow is very functionally
important for them. And what happens is they dig a22

A :“:ˆ: :»:…:w: : A

tunnel, and then it goes to a little nest chamber where

So does this work in zoos? Well, the answer is mostthey can sleep and raise their babies. So even in adefinitely yes. So these data come from a survey oflaboratory cage, you give them a nest chamber with a

23 studies that have been done across zoos all overtunnel; it completely stops stereotypic digging. They

the world. And this data shows that when you giveneed a tunnel going to a nest chamber to feel safe. And

environmental enrichment stereotypic behavior falls;

if they donʼt have the correct type of nesting chamber,

typically, it falls by about 50%. So on the whole, giving

they would carry on doing this stereotypic digging.

enrichments to carnivores, or primates, or to many

And this illustrates something that professor Ueno

other species, seems a very successful strategy in zoos.

said earlier. You donʼt always have to give animals

And enrichment doesnʼt just reduce stereotypiccompletely natural stimuli. You can give them artiﬁcial

behavior, it can help other beneﬁts as well. So this is an

stimuli that satisfy them in the way that natural stimuli

example of work by Ron Swaisgood and some Chinese

do. And hereʼs another example that illustrate that pointcollegues working in the Wolong Panda Breeding

too. Horses are naturally social species; they naturally

center in China. And they found, in this breeding

live in herds. And if you keep a horse by itself, isolated

center, the pandas were having lots of problems ‒in a stable, it will show lots of stereotypic behavior.

lots of reproductive problems ‒ and they embarked

ワークショップ Ⅱ

動物園におけるエンリッチメントの実際

on a big strategy of environmental enrichment. They
redesigned the enclosures, they gave them objects tointeract with, and they made their diets more natural,
so they put bamboo in their diet. And they had lots ofsuccess; it triggered the birth of many babies ‒ here
are some babies here; they look like toys but theyʼrereal ‒ and the enrichments also reduced stereotypic
behavior. So all these examples from wild animals
and also domesticated animals show you that goodenvironmental enrichments prevent or reduce chronic
stress in captive animals, and they also reduce abnormal䇼㪪㫃㫀㪻㪼㩷㪊㪏䇽

behavior. And they seem to do this by allowing animals
to escape from things they find frightening, and thatmight include us humans, and it also allow animals tomeet their behavioral needs ‒the high motivations toperform natural behaviors that they would do in thewild. Now, we know this, and good zoo keepers know
this, and good zoo curators know this.

䇼㪪㫃㫀㪻㪼㩷㪊㪐䇽䇼㪪㫃㫀㪻㪼㩷㪊㪍䇽䇼㪪㫃㫀㪻㪼㩷㪋㪇䇽䇼㪪㫃㫀㪻㪼㩷㪊㪎䇽

What I want to do next, for the last section of mytalk, is to talk about things that are a little bit more
speculative, but I think that are interesting because theyshow that enrichment might have some practical uses䇼㪪㫃㫀㪻㪼㩷㪋㪈䇽

as well.

Workshop Ⅱ Zoo Improvement/Enrichment

23

So even if you donʼt care about animal welfare, if
you want to persuade someone that environmental
enrichment is important, you might want to persuade
them that it has practical benefits that are worth thetime, the energy, and the cost.
So letʼs look now at some work on laboratory animals
that suggest some unexpected practical benefits thatenvironmental enrichments might have. Now we donʼt know if these work for zoo animals, but my bet would
be yes. So the type of work Iʼm talking about typically24

looks at laboratory rodents, like this rat, and some of䇼㪪㫃㫀㪻㪼㩷㪋㪉䇽the work looks on mice, and then at the end Iʼm going to

the animals in the small boring cages. Now when there

show you some work done by one of my PhD students

is no challenge, the two groups of animals look theon mink that we keep as a research subject. Now people

same; these two lines are not significantly different.

at work with rodents look at environmental enrichment

But when they are exposed to the challenge of beingof a range or types; so they might keep them in a small

handled, picked up, and grabbed, the control animals

boring cage like this, they might add a few enrichments,

show a big release of stress hormones, and the enrichedor they might keep them in a big fancy cage like thisanimals donʼt. They just cope with the stress, theyʼrefull of toys and novel objects.

just not that bothered about it. And there are many,

Now when you keep rats and mice in enriched cages,

many similar examples. And when it comes to looking

just as we saw with zoo animals, the environmental

at the eﬀects of enrichment on disease resistance again

enrichments typically reduce stress and reduce

we ﬁnd lots of examples too. So for example, laboratory

abnormal behavior. Thatʼs not new. Itʼs nice to see, butrodents are often used to study human diseases. Theyitʼs not new. But what we also see is some other things

can be diseases like Huntingtonʼs disease, epilepsy, oras well. So first of all, we also see the environmental

Alzheimer disease. And in all these research conditions,enrichments improve animalsʼ abilities to cope withanimals that have environmental enrichment showedstress even when theyʼre taken out of that enriched

less severe forms of the disease. So enrichment reduces

environment. So it seems to make animals better able

Huntingtonʼs disease, epilepsy, and Alzheimer disease.

to cope, more stress resistant. So Iʼll give you some

It also reduces the risk of getting infectious disease.

examples. And it seems to make them, sorry, I should

Animals with enrichments also have better wound

say it seems to better able to cope with stress andhealing; so if they are cut, or if they have surgery, they

it makes them better able to cope with disease. So

heal faster. And their immune systems are generally

theyʼre good at coping with challenge. So in this first

better. And some studies even suggest that rodents

example, this is just one example of many showing thatwith enrichment live longer lives. So hereʼs just one last

laboratory rodents within environmental enrichment are

example. If you house a male mice with a nice female,better resistant to acute stress. So in this experiment,

and if heʼs in research where heʼs given a stroke ‒ thisrats were kept in big enriched cages or they were kept

is not a very nice research, but rodents are used in thisin small monotonous laboratory cages like these. And

research all the time- if heʼs given a stroke in the head,

the stressor the rats were exposed to was being pickedmales that are housed with a female recover muchup and handled, which rats typically donʼt like very

faster from this injury than males that are kept on their

much.

own.

So this graph shows stress hormones released by

In more experiments with mice, mice that have prion-

the adrenal glands. Thatʼs what these lines are. The

disease, so, like mad cow disease, mice that have thedotted line are the data from the animals in the big

prion-disease stopped making burrows at a very early

enriched cages. And the control, or the “c line” is forstage in the disease. So again, their giving up of natural

ワークショップ Ⅱ

動物園におけるエンリッチメントの実際䇼㪪㫃㫀㪻㪼㩷㪋㪊䇽䇼㪪㫃㫀㪻㪼㩷㪋㪎䇽

behavior is a very sensitive indicator that somethingis wrong with them. So this might be very practicallyuseful.

䇼㪪㫃㫀㪻㪼㩷㪋㪋䇽䇼㪪㫃㫀㪻㪼㩷㪋㪏䇽

Another advantage of environmental enrichmentthatʼs shown to us on studies on mice and rats is thatenvironmental enrichment improves brain function.
It improve the development of the brain and it also
improves the animalʼs ability to learn and to remember.
And we can see anatomically many changes in thebrain; increased branching in the nerve cells, and even䇼㪪㫃㫀㪻㪼㩷㪋㪌䇽

increased brain weight. And so as a result, an animal
that is raised in a standard, unenriched environment
tends to have a smaller brain that doesnʼt work so well.
Theyʼre basically more stupid, they have less goodlearning ability.
Now the last example I want to give you comes froma study in my own laboratory, done by a PhD studentof mine, Maria Diaz. And we were interested to see
whether environmental enrichment makes animals
more attractive to members of the opposite sex because
one problem we often have with captive animals is that䇼㪪㫃㫀㪻㪼㩷䋴㪍䇽

they wonʼt mate with each other. It can be a problem
in zoos, it can be a problem all over the place. So we

Workshop Ⅱ Zoo Improvement/Enrichment25䇼㪪㫃㫀㪻㪼㩷㪋㪐䇽A :“:ˆ: :»:…:w: : A

A :“:ˆ: :»:…:w: : A

A :“:ˆ: :»:…:w: : A

wondered whether females would prefer to mate withlow stress males from enriched environments. Are
these males more attractive? Do they may be seemas though they may have better genes and that theywould be better fatherʼs for a femaleʼs offsring? And
here we have a female mink, thinking about it. So to
do this experiment, we housed mink in two types ofenvironments. In one environment, they were kept inhome cages that were small and bare. And you cansee here, thereʼs one, two, three, four, five, six, sevensmall, bare home cages and these are the standard

26

A :“:ˆ: :»:…:w: : A

environments. But for half the mink, these home cages

can visit a male on either side. There are little holes

had climbing towers coming out of the top of them. And

here that the female can get through if she wants tothese towers led to wonderful, enriched compartments,

visit a male. The male is too big, and he canʼt get out

and in these enriched compartments, they had toys,of these holes, so all the male can do is to wait andnovel objects, they had flowing water in which they

hope that she will visit him. So hereʼs a female deciding

could swim. They had lots of interesting things to do.

between a standard house male and an enriched

So half the mink are lucky; they can escape from thishouse male who has a tower here that connects toboring cage, and half fun in the enriched cage.
In our experiment, we gave females a choice between

enrichments elsewhere. And sheʼs deciding which malethe males, raised in each of these two environments. So

females preferred to mate with males from an enrichedthis is the female cage, and she can leave it and enter

environment. So here we have the numbers of matings

this little tunnel, and from this tunnel, if she wants, sheand here we have the enriched males and here we have

ワークショップ Ⅱ

動物園におけるエンリッチメントの実際

she likes best. And we found very convincingly that theseals. Iʼd just like to ask your opinion on that. Thankyou.
Dr. Mason:
Thereʼs good data showing that at least in the felids,
small felids, so small cats that are housed near big cats
like lions and tigers, have problems with stress; perhaps
not surprisingly. So I would think that the seals would
have some problems being housed next to the polar
bears. The question is, is it good for the polar bears
to see the prey? And actually, Iʼm not sure, because it䇼㪪㫃㫀㪻㪼㩷㪌㪋䇽

may be stimulating and wonderful, or it may be very

the barren males. So animals that are environmentally

frustrating; like always seeing candies in a candy store

enriched are more attractive to the opposite sex.

that you canʼt get to. They see these delicious seals and

So all these studies from laboratory rodents suggest

they can never get to. And itʼs really not very nice for

not only that environmental enrichments can reduce

the seals. So my instinct would be that itʼs not a very

stereotypic behavior and reduce stress in the homegood idea.

environment, but they can also have beneﬁts out of that

Audience:

environment as well, improving animalsʼ abilities tocope, and maybe having other practical beneﬁts that wehavenʼt yet measured in a zoo situation.
So just to conclude, then for zoo animals we know

Thank you very much.
Dr. Ueno:
Other questions?
Audience 2:that environmental enrichment can reduce stereotypic

In experiments, in the case of animals, those withbehavior, it can improve infant survival, and it can allow

enriched environments, you said were more attractive

animals to perform natural behaviors. And work on rats,

to the opposite sex. Can the same be said for people?

mice, and mink in research laboratories, also suggest

Dr. Mason:that environmental enrichments may well improve

Is it true for humans? Yes (laugh). Yes particularly,

abilities to cope with stress and disease, improveitʼs terrible to say this, but in human females, females

animalsʼ cognitive abilities. It may improve humansʼ

are interested in resources and money more that men

abilities to detect illness at a very early stage which

are interested in them. So yes. So across all mammals,

would be useful for vets, and it may make animals more

females are looking for a mate that can provide a good

attractive as mates to members of their own species.

territory, good genes, heʼs showing resistance to stress,

So thatʼs it. Thank you very much.

he doesnʼt have diseases, heʼs big and strong. So a malethatʼs raised in an enriched environment whose not

Dr: Ueno:
Thank you, Georgia. Does anybody have any

stressed, and whose not going like this with stereotypic
behavior, is probably more attractive. There are nicequestions about this presentation?

data from humans, there are nice data from lots ofAudience:

species.

Thank you very much for your very, very interesting

Audience 2:

lecture. I suppose, since Iʼm asking you, I should ask in

So could you give me some advice on what kind of

English; itʼs might be easier. Reading your abstract, youenvironment I should put myself in, in order to attract

mentioned something about predators and prey being

the opposite sex?

very close together and that being very stressful. It

Dr. Mason:

wasnʼt in your lecture, but recently weʼve read that oneof the Japanese zoos is planning a polar bear enclosure
where the polar bears has access to a glass window to

I donʼt know. You can judge as well as me.
Dr. Ueno:
So maybe one more question?

Workshop Ⅱ Zoo Improvement/Enrichment

27

Dr. Ueno:

Audience 3:
I heard lots of interesting things about stereotypic
behavior. There is behavior such as pacing, that

Dr. Mason:

happens as displacement behavior due to the lack ofUmm, itʼs diﬃcult for me to comment, but I guess Iʼthe ability to engage in other behaviors, and there

d say, when animals donʼt want to be seen we mustis behavior that remains as a habit even after therespect that. When animals want to be seen, itʼsenvironment is changed. I would like to know if there isfantastic and of course thatʼs why we go to the zoo. But

a structural diﬀerence between the two.

if they donʼt want to be seen, I think we mustnʼt force

Dr. Mason:them. So maybe we have to educate the public. Well,

Thatʼs a very good question. So, I showed you data,

the animal wants its privacy now, so sorry, just move toshowing that when animals have enrichment behavior

the next enclosure. Or we have to pick our species withdrops by half but it doesnʼt disappear. And to somecare. Some species just do fantastically and donʼt mind.

extent it may fall because some of the behavior changes

And other species are very sensitive. So maybe thatʼsand just looks less ugly. And I think in cases like that,the solution. So I donʼt know if thatʼs a good answer, but

enrichment either isnʼt enough or itʼs given too lateitʼs the best that I can think of.

and changes have happened in the animalʼs brain andYes, you just gave me the exact answer I was looking

itʼs too late then to have a good eﬀect. So for a reallyfor. Thank you.

successful enrichment it needs to be good enough for

Audience 4:

the animal and it needs to happen early, at an earlystage before it gets too fixed. Does that answer your

Are the zoos in your country private, or public?
Dr. Mason:question?

Well, I have two countries because I am English

Dr. Ueno:and I live in Canada. So in Great Britain, the zoos are

There may be more questions, but letʼs wrap this up

a mixture of privates and some owned by the city.

for now and move on to the next presentation.

And Iʼm less sure about Canada, because I donʼt really

Dr. Ueno:

understand the country yet, but most zoos are operated

How do scientists relate with zoos?

as businesses as though they are private enterprises.
Audience 4:

Dr. Mason:
Collecting scientiﬁc data in zoos is challenging , andSo do you think thatʼs the main reason that there are

I think thatʼs why it maybe does not happen enough.

such differences between the two countries? England

The challenges are, at each zoo there just very few

and Japan.

animals. So if you want to collect lots of data, you need

Dr. Mason:

to visit multiple zoos, and then that costs money. And

I honestly donʼt know because thatʼs such a complex

sometimes if youʼre lucky a scientific funding agency

question. And itʼs questions about how people perceive

would pay, but if that isnʼt the way things operate here,

animals, why people go to the zoos. I mean thatʼs a

and I donʼt know, then the zoos have to pay. And thendeep question. I donʼt think itʼs just structural, I think itʼ

the question is, do the zoos want to pay to find out

s cultural.

that some of their animals are stressed? And thatʼs the

Audience 4:

problem. But I think youʼre right; I think itʼs importanthusbandry must be objective, it must be based onevidence, or the same mistakes get ignored over andover again and they happen over and over again. Mostof the problems with zoo animals are solvable, but theyʼ
re solvable by looking at things objectively. And for that
I think youʼre right; you need data. And thatʼs all I cansay. I agree.

28

What do you think of visibility of animals in zoos.

ワークショップ Ⅱ

動物園におけるエンリッチメントの実際

So you think itʼs not that simple. Okay, I got it. Thankyou.