Dema (male) a 26-day-old endangered Sumatran Tiger cub cuddles up to 5-month-old female Orangutan, Irma at the Taman Safari Indonesia Animal Hospital in Cisarua, Bogor Regency, West Java, Indonesia.Dimas Ardian/Getty Images

Love conquers all on Valentine's Day, even the instincts of animals that normally have nothing to do with each other. Unlikely bonds between different animal species show that love can be blind, even for predators and prey. Follow some of these most surprising animal friendships.

In 2007, a mother tiger rejected Dema and Manis, two endangered Sumatran tiger cubs. Staff at the Taman Safari Animal Hospital in Indonesia introduced the tiger twins to the orangutans Nia and Irma, who were also orphans. Caretakers later separated the quartet as they got older before any natural instincts towards animosity could arise, reported The Hindu.

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Miwa-chan, an abandoned baby Japanese macaque monkey, first hitched a ride on the back of Uribo, a young wild boar, in 2010, under the supervision of their veterinarian, Akihiro Nihonmatsu, at the Fukuchiyama City Zoo in Kyoto Prefecture, Japan. Miwa still takes piggyback rides to the delight of zoo visitors and YouTube viewers alike. Nihonmatsu wrote a book about the pig/primate pair.

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Kasi, a cheetah cub, and Mtani, a Labrador puppy, grew up together at Busch Gardens in Tampa, Fla. The pair first met when Kasi was 8 weeks old and Mtani was 16 weeks. The two would race around their enclosure and nuzzle cheek to cheek, as adolescent cheetahs do in the wild. Recently, animal caretakers separated the pair, according to the Busch Gardens website. Mtani went home with a caretaker, while Kasi was introduced to another cheetah.

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In another instance, a dog became a big cat’s surrogate mom. The feline mother of this 2-month-old tiger cub rejected her after giving birth in a circus menagerie. The cub, named Cora, became the adopted youngster of a mother dog in northern France in 2004. The mama dog fed the cub along with her own puppies.

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In 2012, Cleopatra, a Shar Pei, took in two endangered Amur Tiger cubs. The tigers' mother rejected them at a zoo in Sochi, Russia, site of the 2014 winter Olympics. The tigers, named Clyopa and Plusha, suckled milk from the dog and slept nestled at her side like puppies, reported The Daily Mail. The tigers played with the mother dog's own puppies and a cat in the home of the canine nanny's owner, Yekaterina Khodakova.

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Owen, the baby hippopotamus, and Mzee, the giant Aldabra tortoise, bonding in Haller Park. Antony Njuguna/Corbis

In December, 2004, rescuers saved a baby hippopotamus after his family washed out to sea in a tsunami on the eastern coast of Africa. After being placed in a pen at the Haller Park Animal Shelter in Mombasa, Kenya, the baby hippopotamus (named Owen after his rescuer) hid behind a 130-year-old male Aldabra tortoise, named Mzee. Owen then followed Mzee around their enclosure, licking his face occasionally, reported the BBC.

Eventually, caretakers separated the two and introduced the growing hippo to his own kind. Like the piggyback-riding macaque in Japan, the hippo and tortoise pair became the subject of a booK: "Owen and Mzee: The True Story of a Remarkable Friendship.”

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A young buck took the place of an absent gander and stood guard at a nest, after a Canada goose laid her eggs in an urn at Forest Lawn Cemetery in Buffalo, N.Y.

The buck lived in the cemetery and would prance alongside joggers when he wasn't guarding the nest, according to the cemetery’s website. On April 27, seven goslings, or goose chicks, hatched from the eggs while the doting deer watched.

“Imagine if we all followed the example of the deer and looked out for each other, whether we are ‘supposed to’ or not,” said Joseph P. Dispenza, president of Forest Lawn, on their website.

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Shere Khan the tiger, Leo, the lion and Baloo, at the Noah's Ark zoo in Locust Grove, Ga. Barcroft Media/Getty Images

Lions and tigers and bears terrified Dorothy in the “Wizard of Oz.” However a real-life trio of those predators found a happy life together after serving as pets for a drug dealer in Atlanta, Ga. Police saved the animals after busting the dope kingpin, who owned the animals since they were 2 months old. Now, Shere Khan the tiger, Leo the lion and Baloo the bear share an enclosure at the Noah's Ark zoo in Locust Grove, Ga. Zoo staff decided to keep the animals together because the creatures had bonded during their confinement despite the drug dealer’s squalid livid conditions.

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The female tiger shown here struts with fashion-forward piglets dressed to match their surrogate mom at the Sriracha Tiger Zoo in Pattaya, Thailand. The tailoring for the pigs is purely for tourists.

But all is not warm and fuzzy at the tiger zoo. An animal rights organization, the Animal Welfare Institute, condemned the zoo for lax security, use of tigers and elephants in dangerous circus performances and allegedly selling tigers to China for use in traditional medicines.

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The situation reverses for sows and tiger cubs at the same zoo where the tiger mom and piglets reside. Above, one-month-old tigers nurse alongside piglets during a demonstration for tourists at the zoo.

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Most encounters between polar bears and sled dogs involve bared teeth and potential battles to the death. However, sometimes, the animals leave their natural animosity aside. In this photo, a chained sled dog seems to want a belly rub from a polar bear. Perhaps they bonded over their similar wardrobe.