It's important to remember humans aren't the only ones who take extraordinary steps to protect, nurture and raise their young. The animal kingdom is flush with moms that take the time to teach their babies how to find food and protect themselves against the elements. Here's a look at five outstanding animal mothers going the extra mile for their young. We collected 12 touching examples for you proving that a caregiver's love doesn't have any boundaries in size or species.

Albert the sheep and Themba the elephant: After 6-month-old elephant cub Themba was orphaned and left by her herd, the workers of Shamwari Wildlife Rehabilitation Centre in South Africa decided to save her life. At first, Albert the sheep was a little aggressive toward this stranger, but later his heart melted and he became the baby elephant's friend and mentor.

Owen the hippo and Mzee the turtle: In Kenya, a little baby hippo was saved after being isolated from his family during a severe tsunami. The 650-pound cub was given the name Owen and was placed in an aviary with a 130-year-old turtle named Mzee. At first, Mzee didn't like its new neighbor, but later Mzee turned into Owen's mentor for 2 years. The story of this couple is so famous that several books and a website have been dedicated to it.

Sai Mai, a 26-month-old tigress, plays with piglets at a zoo in Thailand's Chonburi province, 80 kilometers (50 miles) east of Bangkok. The Royal Bengali tigress was born in captivity and breast-fed by a sow for four months after her birth. Piglets even sleep on the tigress! The zoo is trying to boost visitor numbers by teaching domestic animals such as pigs, and wild animals such as tigers, to live together in harmony from an early age. This is really an extraordinary example, since at the first glance you can just think how those piglets are going to get swiped, and yet, the story turns around.

Niv the macaque monkey and a chicken: A black macaque monkey named Niv lives in an Israeli zoo in the city of Ramat Gan. Niv couldn't find a companion among its own species and started taking care of a chicken from a neighboring cage. Niv coddles the bird that always runs to him when it's feeling scared and is seeking shelter. Sometimes, the bird even stays overnight.

Tita the cat and a squirrel cub: A resident of Colombia, Ruben Gaviria, rescued a wounded squirrel cub and presented it to his cat that was breastfeeding her own kittens at the time. The cat accepted the squirrel as one of her own and the squirrel got his strength back pretty quickly. By the way, this is not the first known case of a cat nursing a squirrel. There was another case where a squirrel cub named Rocky was nursed by a cat named Emma. And she even taught him to purr like a cat.

Kamunyak the lioness and oryx calves: The lioness Kamunyak ('blessed one') has adopted about 6 oryx calves since she had killed the mother of one of the cubs during a hunt. The lioness couldn't breastfeed the weak calves so she called on humans for help. She let them feed the babies under her guidance. Unfortunately, the lioness couldn't protect all "her calves" from being attacked by another lions' pride.

Marquis the cat and puppies: A brave cat rescued 6 puppies last winter in Anapa. Not only did she keep them warm, but she was also catching mice for them to eat. A big family was accidentally discovered by volunteers and today both puppies and the cat have found their forever homes.

Ruby the dog and 'Edgar's mission': There are many amazing animals living in an Australian center called 'Edgar's mission.' This center rescues animals that have suffered from harsh abuse by humans or that have inborn illnesses. Ruby the dog lives there among these animals. Her first owner bought her to guard his sheep but soon figured out that the dog couldn't perform this task and asked his friend to shoot the dog. At the last moment, the friend took Ruby to 'Edgar's Mission.' Ruby has been living at the center since 2009 and has helped many orphaned cubs adjust and get back to a normal life. She became a mother to piglets, calves, a pony, etc. Ruby performs the job of a true vet nurse at the center.

DoDo the chimpanzee and Aorn the tiger cub: DoDo — a 2-year-old chimpanzee from Samut Prakan Crocodile Farm and Zoo in Bangkok became friends with a tiger cub and started to take care of it. The monkey became a real stand-in parent for the little tiger and was even feeding milk from a bottle to Aorn, completely unaware that this little creature will soon grow into a huge predator.

Summer the rabbit and kittens: When a veterinary nurse brought home 6 orphaned kittens, she didn't expect her rabbit Summer to befriend them. Thinking that Summer was their mother, the kittens started to climb all over her trying to nurse. Though the rabbit couldn't help nurse them, still she became a good friend to the kittens.

Sperm whales and a dolphin: Amazing cases of adoption happen in the underwater world too. A family of sperm whales that were taking care of a dolphin with a deformed spine had been spotted near the Azores. It's likely that it was hard for the dolphin to keep up with its relatives, so it remained alone and vulnerable until a family of sperm whales adopted it and started to take care of it.