Zoo Photography

How did you first get into zoo photography?

I'm in zoo photography since 2007 as I remember, but my first good photos were made starting from 2011.

I first got into zoo photography in 2007 when my mom bought me a zoo membership and a small point and shoot camera. So I made trips to my local zoo (The Oregon Zoo) almost DAILY! Before that I was taking pictures around the house and my grandparents' property out in the country with an APS camera

I had always had an interest in photography, but it was my dad that initially got me into zoo photography specifically. During a trip to the zoo when I was about 14 years old, he let me borrow his camera (it wasn't a very good camera; an old Sony something-or-other that also shot video and night vision, haha). As soon as he put that camera in my hands, right off the bat, I wanted to shoot photos of EVERY animal in the zoo (a hefty endeavor, considering the size of the zoo). Since time was limited though, I settled on the big cats and the bears, spending 30 minutes or so at each exhibit (the African lions, the Amur Leopard, the Polar Bears, etc). I would carefully consider my angles, wanting to get the "best shots". From birth, I had had a deep affinity for animals and all of nature and from that day forward I knew that I wanted to capture what I saw through the medium of photography (or try to at least!)

You might be surprised, but it was simply vanity. When I joined DA, I started publishing some tiny drawings and sketches. None of them got popular, but I was still happy – until I once visited a local zoo with a crappy old camera, taking and then posting some really bad blurry photos of wolves and other animals. And these got to be much more popular than my drawings! So next time I tried harder, using a bit better (but still cheap) camera of my parents. And I learned to love zoo photography I know that it might not be accurate as animals are still in human care and within limited space, but I think there were also some hunting instincts awakening in me. I fell in love also with several particular animals in the local zoo – Attila the alpha artic wolf, or our blue-eyed polar fox for example. I tried visiting other zoos, meeting with friends. The initial attempt to get some more faves grew into a big and wonderful hobby. Believe it or not, I did not like zoos when I was a kid, I was scared when my parents wanted to take me there. As a teenager, I also went through the “all zoos are cruel prisons for animals” stage. But I did not only photograph, I also learned a lot about zoos in general, their purpose (which is still changing and progressing even in the 21th Century). I was also lucky to meet some interesting people, so I got info on how it works behind the scenes, so I really admire the work zoos do. And of course I got to study more about animals. Finally in 2010 I bought my first (and current and probably also future for budget reasons) SLR camera – Canon 500 with 55-250 IS kit lens. And for the next few years, a hobby turned into obsession. To be honest, I miss those years a bit, hanging with people I liked in various zoos, not just visiting and taking photos, but also spending some nice time together.

I’ve always been interested in animals, and it was around the end of my sophomore year in high school that I started taking an interest in photography. I saw really stellar wildlife photos from photographers in magazines like National Geographic – the likes of Nick Nichols and Mitsuaki Iwago, and Chris Johns – and I really wanted to try to take pictures the caliber of what they could produce.
My first trip to the zoo for photography was done with a disposable point and shoot camera. I took what I thought were going to be great photos, but when I developed the film, I was profoundly disappointed with the results, so much so that I almost gave up on the spot. However, my mom gave me a then 35-year-old Ricoh SLR and told me to stick with it, and a bit more than a decade later, here I am.

I love animals and photography. I took pictures of my animals (cats and dog), who are more interesting than humans to me, there's something in their looks. So after I bought my Pentax, I decided together with my boyfriend, to take photos of birds in a small zoo in our city because I love their colors. We choose zoos that respectful of and to their animals. I don't have enough money to see animals in their natural environement.

I was in zookeeping and always made photos anyways and so this part of my photography got bigger and bigger. Even now, working as a professional photographer (but in a different field) I still come back to "my" animals.

I've always been a huge fan of animals and nature in general for as long as I can remember, and was constantly begging my parents and grandparents as a child to take me to the zoo. Not to mention, I had TONS of nature and animal related books (and still do). So I definitely got into animals and zoos, before I got into photography. Actually taking pictures is something I inherited from my dad who has always dabbling in photography, but I didn't start trying to take the odd pictures of my own until we got our first digital camera in 2005, which greatly reduced the cost of potential fuck-ups and, understandably, made it a much more reasonable thing for my parents to let me have a try at the whole photography thing. It wasn't until 2009-2010, however, that I really started practicing photography as a more serious hobby, but as soon as I did, animals soon appeared on top of my list of preferred subjects

I've actually written a tutorial back in 2013 which answers this question in detail: Zoo Photography Tutorial - Getting Started

I typically take my camera body (Nikon D5300) and at least two lenses, one shorter (18-55mm) and one longer one (55-300mm) Both are a 5.6 f stop and are lenses that came with the camera in a kit. I also bring extra memory cards and batteries, including the charger! This is all stored in a backpack style camera bag. Aside from camera items, I carry around a water bottle (stay hydrated! Especially during the summer!) granola bars or other snacks, and weather depending clothes (rain jacket, hat, etc.).

I just take my camera (a Canon 5D Mark III), three charged batteries, 2 memory cards, and I carry it all in my camera bag. I tend not to bring a flash to the zoo, as I feel it is disrespectful and bothersome to a majority of the animals.

It depends – I live in a small country (Czech Republic in Central Europe), and we have some 15 official public zoos, which means at least one of them is always very close. For example from my flat it takes me 40 minutes to get to zoo Prague. And when I am visiting my parents in Brno, my former living place, it takes 15 minutes to get to the local zoo with artic wolves. So I usually take only my camera, cell phone and money. When it is a longer trip, I take a snack or a bottle with water. My camera gear includes three memory cards (16 GB altogether), camera itself, my kit lens and battery.

I’ve got two bodies and two lenses that I use, along with a tripod. The bodies are a Nikon d90 and d5000, and the lenses are a 28-200mm f3.5-5.6 and a 300mm f/4. Primarily I use the d5000 and 300mm for depth of field and reach, and the tripod is equal parts for stability and for keeping people out of my way. The 300mm lens has become critical to my photography over the years, because the shallow depth of field that the f/4 gives me lets me shoot through most fencing as though it weren’t even there, while still blurring the background if the animal is close enough.

Usually I spend all day in the zoo so I take my Pentax K5-II, my 120-400mm, a backbag , water, patience and something to eat!

The equipment I feel that fits best for what I want to do. Important are often long lenses. My favorite is the Nikkor 300mm 4,0.

My Nikon D7000, lots of memory cards and something to wipe my lens with when needed. I don't have the money for a telephoto lens, so the Sigma 18-200 mm lens which typically sits on the camera stays on all the time and most of the time it's enough to get decent results. (In fact, the camera itself as well as the lens are actually my dad's property, I just borrow them so often that the ownership status has become fairly blurred )
Aside from that, I always wear hiking boots and sturdy clothes so I don't have to think twice about getting on my knees in the dirt or awkwardly draping myself across fences in order to get the perfect shot.

I've actually written a tutorial back in 2013 which answers this question in detail: Zoo Photography Tutorial - Taking Photos Through Fences

The main challenge I encounter is usually the weather. I'm not a huge fan of shooting on bright, sunny days and I seem to be encountering a lot of them as of late. Other challenges include the animals themselves. Sometimes they choose to stay off exhibit or hide on exhibit which means no pictures for me (which isn't a bad thing, don't taunt animals to come out of hiding just for a picture!) and other zoo visitors. Other visitors aren't a bad thing since they are also supporting the zoo and are there to have a good time, but I will admit I love visiting zoos when they are near empty! But it's always good practice to respect each others space and not to out-crowd other visitors just to get a shot.

The main challenges I tend to encounter are weather, reflections (on exhibits surrounded by glass), hiding animals and other zoo visitors. I favor visiting zoos on cloudy, overcast days, as the animals tend to be more active (since the heat is not so overwhelming). Plus, the colors 'pop' more in my photos since the sun isn't washing out the lighter tones of my subject(s). Shooting photos through glass can also be a challenge. Sometimes the glass is dirty, or there are reflections, etc. However, despite the difficulties, I have shot countless photos through glass with a good end result. I always try to get down (or up) to eye level with the subject I'm shooting and I ALWAYS shoot at an angle through the glass (I never position my lens parallel to the glass). This helps to reduce most, if not all glass glare and reflections. Another challenge is animals hiding in their exhibits. Sometimes they just don't want to come out and say hi, or they just want to take a long eight-hour nap
When this happens, don't get frustrated, just move on to another exhibit and come back before you finish your zoo day. The animals are most active early in the morning and in the evenings. Other zoo visitors can also be a challenge as well, especially when the zoo is crowded. You want to get your shot, but there are tons of kids/families in front of you, and you just have to be patient and wait. I also run into a lot of kids screaming at the animals like, "Hey Tiger! Look over here! Come here tiger!" I know that kids are kids and they like to use their "outside voices" when they're not at home, but it can be bothersome sometimes. I also work for Disney and I have experience working with kids, so, I try to start a conversation with them sometimes and ask them what their favorite animal is or how cool they think the tiger is (the one that they're screaming at, haha). The kids either get very quiet and shy or they get excited to talk to me about the animal they're looking at. This is an awesome opportunity to get them to calm down a bit and you can even share some facts about the animal(s) to better educate them about the world around them. A little goes a long way.

Animals themselves. You can travel 400 km to see some animal of your dreams and you can spend 12 hours right in front of the exhibit with your camera ready, but the animal itself does not have to appear at all. This is a risk you need to take. I often see people being angry that animals don’t pose or are hidden. But I must say I am very grateful that modern zoos allow the animals to enjoy some privacy if they need it. Times of menageries where animals were kept in concrete cells, fully visible as visitors paid to see them are fortunately over! Also especially in foreign zoos, various barriers between visitors and animals are big troubles. When I get fascinated by some particular zoo, it is usually because it keeps some particular animal I would like to shoot – like black wolves, hummingbirds, dolphins, Cape foxes… My budget is very limited and I can afford only 1 foreign trip a year, so to prevent myself from being disappointed, I always study the zoo on the internet first. I google photos taken in front of the enclosure which is the most interesting for me, I study the mesh/glass between people and animals, I study if photos always have reflections of glass or not… and then I decide to list the zoo between “a must see”.

There are a bunch of challenges that I could list – rampaging children, lighting, bad glass on exhibits, fencing/glass with direct light shining on it, but I think the two big challenges on every visit are patience and preparedness. Patience to stick around long enough to get the shot, and preparedness so that I’m ready to get that shot the instant it happens. Preparedness is the big one for me, because a lot of times, you’ll sit around for 15 minutes and get about a 2 second window right at the end where the animal hits that perfect pose. My mind tends to wander a bit too much for its own good while I’m waiting sometimes.

Kids from school by example who act excited in front of me so I can't see the animals, weather, people with no respect.

Visitors… Plain and simple

*Dirty glass;
*Reflections of other people's clothes in the glass (me and my husband tend to wear dark clothes with no print, I often use his dark reflection in combination with my own to create a reflectionless part of the glass to shoot through);
*Very sturdy thick fencing, especially when you're not allowed close-by, these things may be impossible to blur out completely;
*Not getting angry with people who keep using flash on zoo animals.

In the first place, there are differences between wild animals and domesticated animals. Wildlife is always dangerous, and you never really know how wild animals will react. One thing for sure: I wouldn't want to take photos of tigers in the wild, on the same distance as I did at the zoo without glass.

Photographing animals in general isn't as easy as it seems. I personally don't make noises at zoo animals to get them to look over at me, or do something otherwise distracting just so I can get a shot. Also, no petting the zoo animals unless it is a designated petting area (those tigers are most likely not in that area).
Domestic animals, as long as you have permission, you can usually get away with a few tricks to get them to focus on you, by calling their name or holding up a treat or toy. Your own personal pets generally like you and will pay attention to you when you're around (except for my cat because she's an independent beast who ignores everything). Though sometimes they can get too close and just want to be petted, which makes it harder to take pictures as I've experienced with a friend's super lovey fluffy cat!

Shooting photos of domestic animals and wild animals are similar in many ways. I think the most important thing to remember is to always respect your subject. You are shooting photos of a living being, not a 'thing.' Always be aware of your surroundings to make sure that you and your subject are safe. One of the obvious differences though is that you're able to more closely connect (photographically) with domesticated animals most of the time (dogs, cats, birds, horses, sheep, etc.) and you can be a bit more proactive when interacting with the animal you're photographing. For example, when shooting photos of a dog, you can give him a toy to prompt him to be playful for your photo shoot. You can talk to him and pet him. In regard to wild animals, I never try to manipulate them or their surroundings to get the shot I want. I never touch them. I respect that boundary. I do not want to scare them or alter their behavior.

I will be completely honest: although zoo photography has some special challenges, I am sure wild photography is definitely much more difficult. You need to track the animal, you need to know its habits, you need a BIG portion of luck to even see it, not talking about taking photos. It is really close to hunting. In zoos, you might fight with double fences which get into your view, but the animal is still located in 20x30m exhibit. Often you just wait – with a hot dog in your hand – until the tiger simply wakes up and gets close to a pool to have a drink. So I have big respect and a little bit of jealousy for wildlife photographers, who really take shots of wild animals (and I mean really wild animals, not tame foxes, owls and other creatures which are often used for “wild photography” workshops).

I think the main difference with zoo photography is that you know where the animals are, for the most part, and you can better predict where they’re going to be/what they’re going to do ahead of time. It lets you prepare more thoroughly, think through the possibilities, set up your shot, and try to anticipate the action better than with traditional wildlife photography. It follows that the possibilities tend to be a lot more finite than with traditional wildlife photography, especially if you frequent the same zoo many times, but even then, I think “learning” your zoo really helps you prepare better for shots when they do present themselves.

I love animals for their "souls" and how a look/picture can show their emotion, their past.... Even in domesticated animals I prefer to take pictures of shelter's cats and dogs, for example. I think we have to choose where we are taking pictures, the respect for the animal is essential. Wild animals are always more "impressive" and also more difficult to take a photo of because they're not close to us, it's another challenge.

First of all, zoo-animals are all but domesticated. They are still wild and fierce animals.
In the wild (where I also shoot) much is luck or connected with a lot planning. In zoos you know the exhibits, the animals and the best time for the best light. But both fields need skill and patience.

Without doubt the predictability of the shots. When I'm taking pictures of my dog, I can simply take him to the setting I like and practically have him pose for me the way I want, like a human model. While not all domesticated animals are of course as well trained as dogs, they generally allow you to handle them, and place them in particular spots, thus making for easy manipulation of the desired background and lighting. With wild animals, in zoos as well as in the actual wild, you can't do much more than hope something interesting will happen, in a spot that allows you to position yourself for decent lighting and a nice background. And of course, the wild adds the additional challenge of finding the animals first, and then finding a happy medium between getting close enough for the shot and staying far away enough to not endanger yourself and/or disturb the animal. I do feel like the additional challenge of wildlife photography in and outside zoos, make for extra satisfaction afterwards when a picture does turn out with all the elements in place exactly like you wanted them to.

No, never. Of course, it's much cooler to show photos that you've made in the widl, but not many people can afford it. And shooting squirrels in the woods and call it cool wildlife photography? Ridiculous.

I can't recall ever getting chastised for taking pictures of animals in a zoo. I'm pretty open with sharing if my photos are of animals in the wild or captivity, so I don't have anything to hide there. If anything, I think the zoo photos get a lot of praise, especially from other people who have visited the same zoo, or from the keepers themselves if they're lucky enough to get around that far!

I have never experienced scorn or any sort of negativity for shooting photos at a zoo. As I shoot both at zoos and 'out in the wild', I try to capture both 'worlds' in the best and most honest fashion that I am able to. The only negative aspects of zoo photography I can think of are the abhorrent conditions zoo animals have to live in sometimes. I do not just capture 'pretty photos of animals' all the time. If there is a chance for me to help make a change for the better, for humans and animals alike, I will do my best to be heard and to share with others. Whether that is shooting photos of rhinos housed in small concrete bunkers or shooting photos of gorillas (highly intelligent and sentient beings) with severe depression from lack of environmental enrichment and social interaction with others of their own species. Images do truly speak louder than words sometimes, and capturing the not so 'pretty' side of life can definitely help to spark change for the better.

Only very few times (1-3?) during my 9 years here on DA, so it is really a minor experience. Sometime people complain on SEEING animals in zoos in general, protesting against zoos. But I also went through a anti-dolphinarium and anti-zoo stage, and now I support modern marine/animal parks. So I understand it, I am just mad when some people are trying to “teach me”, although they base their arguments on ideological materials (Cove for example) and they obviously refuse to even consider arguments from the other side.

I get comments every now and again on submissions along the lines of “poor animal” and “zoos are the worst,” but for the most part, I’ve been lucky enough not to have any scorn thrown my way. I do do some traditional wildlife photography as well, but a lot of the animals I photograph in zoos are not animals that I would ever see in the wild. For Sumatran tigers or Micronesian Kingfishers or clouded leopards or gharials or any number of other animals, it’s zoo or bust – these are animals that you aren’t likely to see, even if you do go looking for them in the wild.

In zoos where animal are like prisoners, yes or if they look sad and annoyed.

Not one day.

No, not at all actually. I think most 'actual' wildlife photographers understand very well that not everybody is able to invest the time and money it requires to get gorgeous shots in the wild, especially if photography is only your hobby and not your profession (e.g. the fact you have to travel to where the animal lives which, depending on where you live, could be ridiculously expensive, might need to hire an expert to actually find the animals and depending on the type of animal, might need to spend weeks waiting for the perfect occasion and will most definitely need expensive equipment such as telephoto lenses to get good shots from a safe distance without bothering the animal). In fact, several of the professional wildlife photographers I've gotten to know here on DA, combine zoo photography and 'real' wildlife photography themselves. I've also found that my 'training' as a zoo photographer has been an immense aid in being able to get proper shots of animals in the wild whenever I get the chance such as in Canada last year (wild bears, marten, coyotes, mountain goats, deer...), or in Norway this year (Musk oxen, Northern gannets).

There is the opinion that zoo photography is easy to do, but let me be honest: do we really see that much good zoo photos? I don't think so. Most people do snapshots. Looking at animals ant taking pictures of them are two totally different things.

Like all photography, it captures a special moment in time that can be cherished for as long as you have the file or physical print. These moments are especially important when the animals that you've been spending time with passes away. These moments, majestic or goofy, bring back really nice memories when you're looking through albums.

Each photographer will obviously experience the journey of zoo photography (or photography in general) differently. Even so, from personal experience alone, I think zoo photography is special because it has taught me patience (with others and with myself). I have also been humbled on more than one occasion by my animal subjects and other zoo visitors. No matter how 'professional' your equipment or how many years you have been shooting photos, there is ALWAYS room to learn, grow and improve. Zoo photography helps me to share photos of animals that others might not even know about or otherwise see in everyday life. This is a great opportunity to connect with people and teach them about animals, respecting non-human beings and preservation.

For me, it is just a hobby. Really. I even have absolutely no love or talent for photography. I only love visiting zoos with my camera, taking photos of animals. But when I think about it in depth, I think even zoo photographers can show the beauty and importance of the animals. I always smile and feel pleasure and gratitude when some fellow foreign photographers publish zoo photos of animals I can not visit in my country. Any shot of a Mexican wolf or a grey fox is amazing. I believe zoo photographers can bring some animals people love, to their screens. But they should do more. With my photos, I tried to educate people about particular species and with my journals, I did my best to explain the role of modern zoos and dolphinariums. And the sad role of zoophotographers is preserving some animal species for our kids and grandchildren, because many special animals will simply perish in next years, being exterminated by human activity. Only photos will be left. Sad, right…?

See my previous answer. I think zoos give great opportunities for people to see and learn about animals that they would otherwise never have the chance to. Likewise, I think that’s what’s great about zoo photography – I would never have the chance to photograph lions and tigers and clouded leopards in the wild, and zoos give me a fantastic chance to see them, get to know them, and immortalize those experiences in my photographs.

Like in photography in general, pictures can testify from a period, show the reality.
I don't know if it is important. In case of maltreatment it can be indeed. And it turns special when people who are looking at those pictures don't see they have actually been taken in a zoo.

Yes, you need to show the people what animals there are and that they are important to preserve. Also the pictures tend to make an emotional bond between the animals and the viewer.

It allows people, even those on a limited budget, to practice animal photography on a wide range of animals from all parts of the world from relatively close-by. Like I said, I never would have been able to get the lovely wild animal shots from my Canada holidays last year if it weren't for all the zoo practice I've had. I also believe that any kind of nature photography may help instill awe of our planet and its inhabitants in the next generations and hopefully may help convince them that the natural wonders on earth are worth protecting. In that light it has also been my great pleasure to observe the huge recent efforts at my local zoos to greatly improve the animals' living conditions.

First off, you must love animals and feel them and learn how they'll act. All other things you can read from my tutorials.

For up and coming zoo photographers, take your camera everywhere you go. Also, it's okay not to take your camera and just spend time around the zoo. Don't always go for the high profile animals, spend time with some of the lesser known animals that most people may pass by (hoofstock, reptiles, fish, birds etc.). Make sure you respect zoo rules and boundaries. Don't try and pass barriers to get the shot. It's not worth it! Also, respect the animals. Your hooting isn't going to get anyone's attention, they are used to hearing it.
Remember to have fun, maybe get a zoo membership if you can afford one (they are worth it in the long run and usually pay for their self after a few visits). And attend a keeper chat or two if your zoo offers them!

Just keep shooting! That's what I did, I just kept shooting and experimenting. You don't need a fancy camera to shoot awesome photos of animals. You just need patience, creativity, inspiration and a constant willingness to learn. Animals are unpredictable, so study their behaviors first before shooting to determine when to take your shots. If your local zoo has a yearly membership, you should consider joining for a year. The membership will likely pay for itself after just two trips! This will give you an opportunity to visit the zoo whenever you want and to build your animal photography portfolio. Also, never become discouraged by the work or photography equipment of others. Each photographer is different, and each photographer started off at square one, so never compare yourself to another photographer. If anything, you can utilize the work of others to learn and to inspire yourself!

Love animals.
Respect them. Not just the whole species, but also each individual – if you see it sleeping, just wait. Although you paid for your visit, you are still a guest in the animal’s territory.
Learn about them. To get good photos, study animals - so you know if you should visit them during the morning or later. Find facts, so you know if artic foxes looks great in winter or in August.
Google photos of the zoo you want to visit so you’ll know if local barriers between people and animals allow you to take photos.
Share not just photos, but also your love and knowledge about animals.
Make people admire nature’s creations, although they are kept in human care.
Don’t forget to meet people you like in zoos – at least from time to time.
And enjoy the wonders of zoo photography, which combines presence of animals and a slight bit of hunting we all have in our blood.

More than I can count, but I’ll just give two:
1) I think the biggest thing people have trouble with is being patient. They expect to come to an exhibit and have the animals just start dancing on command. A lot of animals spend their days sleeping, so when you see a sleeping animal, don’t just leave – wait. Give it some time, find some good angles, get prepared. Set up shop and drop your tripod down to stake your claim. It might be 2 minutes or it might be 20, but you will be ready for those two seconds that that animal wakes up and looks around. It’ll be worth it.
(And as an aside, don’t be that guy that taps on the glass, or that whistles, roars or, heaven forbid, throws rocks at the animals in an effort to wake them up for a picture. Don’t even be that guy that uses flash at the zoo. The animals deal with enough terrible people on a day to day basis without you being added to the ranks.)
2) Any wildlife photography is all about the eyes. Focus on the eyes, because that’s where we humans look to first when we see an animal or person in a photo. Likewise, with wildlife photography, it’s not just enough to get an animal with its eyes open – anyone can do that – what you’re waiting for is that split-second chance that makes you say “wow,” where the animal opens its eyes extra or looks up and catches the light of the sky, or its eyes fall into a shaft of sunlight. Look for that extra little touch that takes the shot from “good” to “great” and makes it definitively yours.

Patience, passion, love of the animals. The moments you can take the bests pictures are usually at the opening and the closing

My first tip is: Learn your words, so you don't find yourself looking up the word "budding".
But really: Patience and knowledge of the animals and their surroundings

*Practice on getting your grip on the camera more stable, more quickly so. In fact, this doesn't necessarily require any special practice, it just comes gradually along with trying your utmost best every time you go for a shoot, but it's definitely one of the points where you can make major improvements. The more stable your hands are, for example, the more precise the aim of your focus will be, and the more easily you'll be able to blur out fencing in your shots.
*Your number one priority should be to try and capture each interesting moment in the first place and to get these interesting shots as sharp as possible. Also always shoot at the highest possible resolution. That way you maximize the chance of being able to optimize the images' composition etc. later on at home. A lack of sharpness, however, is something you can never really make up for, nor a missed shot because you were too busy thinking about the perfect framing.
*Don't be afraid of getting yourself in strange or awkward positions to get a good shot. I've often found that after a bit of searching at unusual heights, otherwise dirty glass sometimes offered very nice peep-holes for clear pictures.
*Check your pictures regularly throughout your shoots, to make sure you are getting the proper lighting and are using the optimal settings and experiment with moving yourself around with respect to your subject and using different camera settings if the in-between results are not satisfying. Few things are as annoying as finding out at home you have 50 awesome action shots of a leopard which are all way too dark because you took them directly opposing the sun and didn't notice in your vigour.
*Keep an eye on the background as well. The most beautiful zoo photographs are those that do not show they were taken at a zoo.
*Always take enough pictures of an image you like, even if the animal doesn't move at all. You'll often find out on your computer that one of the 15 or so near identical images is that tad bit sharper than the rest, a difference which you often can't discern on your camera screen at the zoo. And it's not like taking more pictures costs more money, as used to be the case with fim rolls, so why take any chances?
*And last but not least, a very specific piece of advice: I've found big cats to be surprisingly active in late winter (February-March), at least in Central Europe. So definitely try some time to visit zoos in the more unusual months for a change, you might be pleasantly surprised!