You may not be surprised to learn that dogs are by far the most common service animals, assisting people in many different ways since at least 1927. However, the dog is not the only animal that has been used as a service animal. In fact, there are many other, less usual creatures that have been used to help their human owners. From ferrets and hedgehogs to dolphins and kangaroos, here are 25 Of The Strangest Pets To Be Used As Service Animals.

Miniature horse
Much like guide dogs, mini horses can also act as trusted aides for those in need, helping them navigate through the world. Nevertheless, unlike service dogs, miniature horses need to live outside and require a lot more space.
Dolphin
Known for their high intelligence and friendliness, dolphins are sometimes used in emotional therapy. Dolphin Human Therapy, a Miami-based company, provides a full-time, individualized dolphin-assisted rehabilitation program for special needs children and adults.
Donkey
Donkeys are known for their calm and friendly character, which makes them great therapy animals. According to the British-based Donkey Sanctuary, even the most disturbed, agitated children relax when petting or talking to donkeys.
Duck
A little Indian Runner duck named Daniel serves as an emotional support animal for Carla Fitzgerald from Wisconsin who had a serious accident that left her immobile for months. The duck also helps her to recover from the post-traumatic stress disorder.
Ferret
Ferrets have many traits that make them great therapy animals. They are small, easygoing, quiet, litter-trained, social and attentive. Ferrets transport easily and do not trigger allergies as much as other common furry pets and do well with limited outdoor access.
Pig
A pot-bellied pig named Elvis was used as a service animal by a blind teen Alisha Doolittle. Doolittle described Elvis as amiable and well-behaved but she had problems obtaining his certification as local authorities classified Elvis as a farm animal and not a service animal.
Llama
Llamas are friendly and easy-to-train animals which is why they are sometimes used as therapy animals. They are extremely curious and pleasant to be around, which makes them particularly popular among kids.
Parrot
Parrots are known to be very empathetic and tuned into the emotional environment around them. They can sense stress and tension, anger and distress in their owners, before these feelings break the surface. In a famous case, a bi-polar man relied on his African grey parrot to intuit when a rage-like episode was coming on and encourage him to calm down.
Rat
Rats can be used as therapy animals for children with developmental disabilities as their small size may be less threatening to some children. Rats have also been trained as service animals, to identify damaging muscle spasms for people whose ability to sense this has been compromised by their disability.
Iguana
There have been several cases of iguanas serving as therapy animals. Joseph Wayne Short from Maryland said his 4-ft (1.2 m) long iguana helped him keep calm and Cosmie Silfa from California had an iguana named Skipper who was qualified a “service iguana” by his psychiatrist who had been treating Mr. Silfa for depression.
Monkey
Some monkeys (for example the Capuchin monkeys) can be trained to perform manual tasks such as grasping items, operating knobs and switches, turning pages of a book etc. Known as helper monkeys, these monkeys can be trained to help people with quadriplegia, severe spinal cord injuries, or other mobility impairments.
Kangaroo
In July 2008, Diana Moyer from Wisconsin adopted a baby kangaroo named Jimmy who has been since then serving as a therapy animal for her cancer and depression.
Turkey
In January 2016, Delta Airlines allowed a passenger to have their emotional support turkey with them. According to other passengers, the bird was well-behaved.
Bearded Dragon
Megan Curran from Texas, who suffered from depression and anxiety as a result of heavy bullying from high school, found her emotional support in a bearded dragon named Chief.
Tortoise
There was a case of a woman who took her emotional support tortoise with her on board on a flight. The tortoise, named Herman, allegedly enjoyed looking out of the window during flights.
Rabbit
Rabbits make great therapy animals. They calmly accept unusual or new circumstances, they like people, are controllable and easily-trained.
Goat
Goats can also be used in therapy programs. They are sometimes used in hospitals, assisted living homes, nursing homes, schools, rehabilitation centers, hospices and others areas to help improve well-being of humans.
Wolf
After enrollment in a training course, Kodie, North American grey wolf was certified as a service dog. Kodie, who was adopted as a 6-week old cub, would let his diabetes-suffering owner Nick Battles know when he needed to take insulin.
Hedgehog
Capable of learning certain behaviors through positive reinforcement, hedgehogs can be great tools to stimulate learning and can be also used as therapy animals.
Sheep
Sheep are sometimes used as therapy animals. Benny the Sheep, for example, is a popular therapy animal used at the Nature’s Edge, a therapy center located in Northwest Wisconsin.
Snake
A 5-ft (1.5 m) long boa constrictor named Redrock was used by his epileptic owner Daniel Greene to signal impending seizures. Greene said the snake could see changes in his blood pressure 3 minutes before a seizure. Redrock would squeeze the man´s neck in these situations.
Hamster
Hamsters are usually kept as pets but they are sometimes also used in animal-assisted therapy where they help to improve a patient’s social, emotional, or cognitive functioning.
Cat
Using clicker training, a cat can be taught to alert the arrival of a seizure. Cats, just like dogs, have an innate sense of when seizures are coming. Kittens can also be taught to use a telephone when the owner is unable to call for help.
Cow
Cows are usually kept only for milk and meat but these huge domesticated mammals can also be used as therapy animals. One of the places where cows are used to comfort people is the Rae-Ann Skilled Nursing & Rehabilitation Center in Geneva, Ohio.
Chinchilla
Famous for their ultra-soft fur, chinchillas are popular pets but they have also served as emotional support animals. Similarly to hamsters and bunnies, they are particularly popular among kids.