Surely as a kid you've banged on the gorilla cage a time or two only to get an angrily beating back, but surprisingly, gorillas aren't the mean ones at these zoos...
Those Damn Tortoises

Aldabra tortoises. They have an outdoor pen, but obviously they are stuck in a smaller indoor enclosure during the colder months.
They won’t leave you the f— alone. I was watering the plants at one point, when two big males came up behind me and pinned me to the wall. I pinwheeled my arms and fell onto one’s back…sort of got to ride him.
Other times, the decide to sit RIGHT IN FRONT OF THE DOOR. So you’re stuck until you convince them to move. You certainly aren’t going to move 500 pounds of turtle on your own.
If you put a squeegee against the wall, they simply HAVE to knock it over and sit on it.
Got the hose out? Yup. Gotta sit on it.
Bringing out food? Sit right in the f—ing feed troughs. Source
A Motherly Feeding

Not a facility I work at currently but we had a kookaburra who would catch lizards, snakes, frogs, and even earthworms so he could feed them to you. You would be standing around doing your job and all of a sudden he shows up on your shoulder trying to force feed you a lizard he whacked on the ground 30 times.
Oh by the way if you covered your mouth, why not try the ear? The ear is a great place to put a dead lizard or live earthworm…Source
One Smart Monkey

I wasn’t there at the time that this has happened, but I used to volunteer at the Omaha Zoo, and there was the story of Fu Manchu, the orangutan.
Apparently, one of the keepers found Fu and some of his buddies hanging out outside of their enclosure and ushered them back in. When it happened again, the keeper thought someone was leaving the enclosure open. It happened so much that someone was about to get fired over it.
Finally, someone witnessed Fu climbing through an air vent to get to the door, pulling it open enough to expose a gap, then pulling a piece of wire from his mouth and using the wire to undo the latch and open the door. He’d been hiding the wire in between his gums and lips to engineer his escape.
Only a dick move because he almost got people fired. Otherwise, it was slick as hell. Source
Constant Mood Swings

I’m sure there are probably problem animals in the other areas of my zoo as well but the animal that is the biggest jerk that I have worked with takes the form of a baby camel. Now most people don’t think about camels as dangerous animals usually but a quick google search will show you plenty of videos displaying just how strong and terrifying they can be. Fortunately that’s not an issue for us, all of our camels are well trained and pretty well behaved so long as you don’t leave anything sitting around them that you aren’t prepared to have eaten by one of the giant lugs. Except for one.
This baby camel was orphaned by her mother so she has been raised by us for the most part. Usually she is pretty sweet and fairly easy to get along with. But I have never seen an animal go through bigger mood swings than her. One moment she will be rubbing up next to you looking for attention, but the next moment you have your back turned she will be half reared up and ready to kick, and then after failing to murder you she will try to come back to you for more affection like none of it ever happened. She would use any reason as an excuse to try and attack one of us too. “Oh that stick that has been in my enclosure for a week and I have never reacted to? Now that you are in my enclosure as well it’s now clearly an attacker and I need to destroy everything in my immediate radius.”
Now I know what you’re thinking, it’s just a baby right? What harm could she do? Well by six months she was already past 200 pounds and still growing, she’ll easily pass 1000 pounds when she is fully grown. So trying to lead her outside in the morning when she was in a homicidal mood was a hassle to say the least, dodging kicks and trying to hold onto her lead while she did her best to murder you. I would easily say 90% of the injuries sustained on the job in our department was due to her.
That being said, I still love the little antichrist and she has definitely started to calm down with age and take to her training a lot better but that couldn’t have come fast enough for most of our shins and ankles. Source
Shake Ya Tail Feathers

I used to volunteer at a zoo and the biggest jerks were the ravens. They were really smart and awesome for enrichment activities and for teachings classrooms but if they got bored they would find a way to entertain themselves. One particular time a raven decided to place some of its’ food right outside its’ caged enclosure to lure a peacock, once the peacock got close and started to eat the raven would sneak up and pluck the tail feathers off of the peacock. Source
Honey Badger Abuse

I don’t work there but I have visited a popular wildlife rehabilitation centre in South Africa called Moholoholo (I know right, great name) about 7 or 8 times.
They have at the centre arguably the world’s most famous honey badger, called Stoffel. Now I am sure none of you need an introduction to how f—ing savage these animals are, but this particular bastard has actually featured on multiple TV shows because of his antics.
In the first few years of his life at the centre, he dug his way into the Lion enclosure TWICE and attacked the alpha male of the pride both times. When he kept digging his way under the wall of his enclosure, it had to be rebuilt 2 metres deeper into the soil. When he opened up cracks in the concrete and escaped, those had to be covered with metal sheet. When he used rocks/sticks to create a tower and climb over the wall, they removed them… only for him to steal a zookeeper’s broom and climb out using that.
I know many more stories of his antics, but my favourite is how after years of living on his own they decided to find him a female companion to join him in the enclosure. First thing Stoffel did?
Stood on her head and used her to climb over the wall. Source
Wallaby Snuggles

A hand-raised wallaby named Wallace Montgomery. He was hand-raised (translation: f—ing psycho) and then given to us when he became a wee bit overwhelming for his previous caretaker.
Feeding time? Prepare to be be gouged by his razor sharp nails, bit on your softest parts, and the bowl WILL be knocked out of your hands.
Cleaning time? He will grab your rake and shovel, hit you with them, and kick you when you bend down to pick up your stuff.
Trying to give him fresh straw to sleep on? Nope. He shredded the bag it came in. He kicked the fresh straw into the yard. He picked up the dirty pissy straw and rubbed it all over you.
I love him immensely. Fun fact: if you pick him up mid-tantrum, he will lay his head on your shoulder and give you three solid minutes of snuggles before recommencing your attempted murder. Source
Lessons Learned

Ex-Zookeeper here. Orangutans are super smart, super strong, and super jerks. Well, some are. We had a female who, if you were standing in front of her indoor inclosure, would spit and hit you in the mouth every damn time. And grin. She grinned so big when it happened. Lesson learned. Source
The Reptile From Hell

Not a zoo worker, but a devoted reptile keeper.
This is Wrath, he’s an Argus monitor that measures 72″ from nose to tail and possesses a vendetta against all life. I am at this point convinced he is nothing but pure unfiltered hatred in the guise of an animal.
Firstly, no one but me can even get near this beast. Take one step towards him and he’ll rise up on his hind legs with claws outstretched, ready to go to town. And he’s capable of, and happy to, handily shred a hand with his teeth. He once tore through heavy duty welding gloves like paper.
Secondly, he is sadistic as f—, he routinely skins his prey ALIVE. He toys with live prey, and will even dismember dead things just to facilitate his lust for blood. He is a capable killer, and during his time spent in an outdoor enclosure he hunted down and devoured several birds, rabbits, marmots, and cats, and once a Red-tail hawk.
He is also extremely intelligent and can open doors, undo latches and most importantly, knows how to target specific weak points on prey. When hunting rodents he will strike directly behind the head and literally kill them instantaneously, anything larger is brought down by a bite to the Achilles tendon, and then bled out through the abdomen.
He even killed his new mate after she refused to allow him to mount her. He then proceeded to f— her corpse and has such been retired from further breeding possibilities.
I have no idea what is wrong with this creature, and I’ve never met anything as evil, twisted, and sadistic as he is. All my other animals are perfectly approachable and well mannered, and then I just have this little satan-spawn that is hellbent on the evisceration of all things good. Source
Sweet Revenge

When I worked as a zookeeper intern, I think the biggest jerks were the emus. It was the summer of 2004 and the emus shared an exhibit with the wallabies. The exhibit wasn’t high-security. It was essentially a fence made of dried bamboo stalks.
Wallabies are super cute and while we didn’t have an area where they are in the same space as visitors, some zoos do. Wallabies are not typically threatening in any way.
The emus were big jerks. They constantly pecked at the wallabies and were generally a pain, but they weren’t separated because they didn’t cause actual injuries. The wallabies eventually got their revenge and freedom. One night, one of the emus ran into the fence and sort of gently-impaled itself. It wasn’t badly injured, but it did fall down after the injury. What did the wallabies do? They kicked it in the head until it was dead.
The wallabies and emus were separated the next day.
Side note, zebras are jerks, too. Our zebras shared an exhibit with the giraffes. We had a giraffe platform where visitors could feed the giraffes carrots, grain, and other goodies (according to the giraffe diet, of course). The zebras wanted the goodies and would kick the giraffes so the giraffes would drop their food, then the zebras would eat it.Source
A Pounce

I interned my senior year of undergrad at a zoo and loved it. Wish I had stuck with it. Here are animals I worked with:
Snow leopards: Mom and dad were big jerks. Wouldn’t actively attack or anything, but did not want ANY interaction with us. We had a cub born the day before I started, so I got to help raise this little asshole. We tried to be as hands-on as possible when we weighed her every week, but that little cub was mean. I have scars from her. But it’s a pretty cool story to say you have scars from a snow leopard. Papa leopard almost knocked me out once. I got close to the fence to look for him. The fence was kind of those loose chain link mesh/steel. So it moved if you leaned on it. I went to look for him because we were trying to shift him inside for the evening. I lean on the fence and he comes out of nowhere and pounces on the fence right above my head, then trots inside. I don’t think he was trying to eat me, just knock me on my ass.
Hanuman langurs: assholes. We had a Mom and daughter and they hated anything that was male. Which I happen to be. I cleaned up their poo and fed them, but they still hissed and yelled at me.
Francois langur: this little guy was way cooler than his roommates. He had a faux hawk and knew where treats were kept in my pockets. He would give you a pat down if you came by to visit.
Red pandas: sweetest little things. They’re basically slow and clumsy raccoons. They’d do anything for a grape or biscuit.
Cougars: my favorite by far. These were the two cuddliest giants I’ve ever seen. One was like 100lbs, the other had a weight problem and was easily 200lbs. The smaller was a female and I would have felt very comfortable if there was ever a reason I would be locked in her cage alone. The big guys was very sweet as well, but I feel like instinct may kick in with him. They both loved scratches on their head and cheeks and would purr. They were humongous house cats. Source
Don’t Go Chasing Waterfalls

THIS ONE F—ING OCTOPUS.
I was volunteering at an aquarium in the cephalopod section. One day the power was out, so we were on backup generators and we were running all over to make sure everything necessary to keep the animals alive was still running. The tanks where we kept the giant pacific octopuses (these octopuses are about 8 or 9 feet across) didn’t have a solid top to close it up – instead the top portion of the tank is covered by astroturf. Octopus suckers can’t work on astroturf, so they can’t climb out. In theory.
This bitch jams herself into the water outtake in her tank while no one is paying attention. Water keeps going in, but none can get out. She makes a f—ing waterfall out of the tank and tries to ride it to freedom. We caught her just after she flopped onto the floor.
They’re just too f—ing smart. Source
FREE THE WORMS

I work with squirrel monkeys, and I go in there with a little bowl of live mealworms for training purposes. One day one particular monkey was being fairly grabby, reaching for my hair and whatnot. I had closed up their cage and was getting ready to leave when I noticed I hadn’t slid a hatch shut. I moved closer to the fence to do it and someone – I don’t know who, but I’m bettting it was the grabby one – shot a hand out of the cage, reaching for the mealworms, and knocked the bowl out of my hands. I don’t know if you know this, but individual mealworms are hard to pick up off the floor, especially when they’re crawling away as fast as their little legs can go. And so then of course all the monkeys are on the ground reaching through the fence to grab the worms while I’m trying to scoop them back into the bowl as fast as I can. That must have been the greatest thing ever, like HOLY SHIT FREE WORMS EVERYWHERE
I did also have a capuchin monkey throw food at me. I ignored it because I was observing a different monkey at the time, and out of the corner of my eye I saw the one that I assume threw the food come up to the fence and stick her arm under the door to try to reclaim the food she’d thrown at me, but it was out of her reach. Karma. Source
The Devil Spawn

Swans are pure devil spawn.
They want to kill anything that moves near them. Sweet harmless baby ducks born on the pond? Initiate murder instinct. Man who feeds me and cleans my awful poop everyday? Start up the murder protocol.
Even the dumbest of invertebrates knew that we fed them and would be kinder. Swans see you bringing them food from across the park and are furious that “YOU STOLE MY FOOD I NEVER HAD AND PUT IT IN THAT BUCKET YOU’RE BRINGING TOWARD ME AND I AM GOING TO BEAT THE HELL OUT OF THIS GROUNDHOG NEAR ME BECAUSE OF IT, AND THEN TRY TO MURDER YOU.”
Swans are the worst. Source
Those Damn Bats

Right now it’s the short tailed leaf nosed fruit bat.
I’m an intern in a well known zoo. We have a wet cave filled with probably 1000 of these f—ers. The door is surrounded by a wire cage. When we go to feed them we just let the door open and let the bats fly in the cage. When we leave we have to heard them into the cave. As an intern I’m not allowed to touch them. So I put my hand up by them to guide them.
Except they don’t like that and they’ll fly right in my face and hover there for a few minutes.
One day I was by myself doing it and one of the little f—ers would not get in the damn cave. I stood there for like 10 minutes doing jazz fingers and he just hung there.
Asshole. Source