A mother's response to a crying infant is a universal tug at the heart strings, regardless of traditional species barriers, according to a new study. This may help explain for some exceptionally stunning moments in nature, when mother predators adopt baby prey, or when utterly unrelated species care for one another.

Humans, of course, are well aware of their compassion for baby animals of any species. The chirps of newborn chicks, mews of kittens, and even the tiny snorts of piglets are all commonly thought to be adorable and give rise to strong emotions of love and care. Why else would the internet be largely characterized by puppy and kitten videos?

However, a study recently published in the journal American Naturalist details how this baby-love may be true for a great number of mammals, in which motherly instincts and the cries of an infant in distress share similar elements - prompting even cross-species responses.

This was determined after biologist Susan Lingle and Tobias Riede played recordings of infant distress calls from a wide range of species to wild mule deer out on the Canadian prairies. Stunningly, whenever a call was sounded from speakers hidden all over the prairie, mother deer would rush to the noise, especially if it was at a similar pitch to the cries of baby deer.

The cries of infant fur seals, puppies, kittens, and even human babies all appeared to effectively attract the attention of worried mother deer. Stunningly, even the ultrasonic calls of baby bats would attract the deer if its pitch was first lowered to the ideal range for these deer. (Scroll to read on...)

Now, you may argue then that it's all about the pitch, but non-infant calls in the same pitch didn't have the same effect at, implying that there is something more than pitch at work in these calls - and it's a nearly universal "something."

Lingle recently told New Scientist that this intrinsic response may have been made universal for the sake of simplicity during dire events.

"These are calls that are generally made in a life-or-death situation," she said. "I think the advantage of securing survival for your offspring outweighs the potential for error."

However, there may be more to it than that.

Motherly Miracle Cats

Large predatory cats have always been considered clever, and they too have been seen rushing wide-eyed and full of concern towards the calls of any distressed infants. What's more stunning is the fact that even after they recognize that the distressed infant in question is not of their own species, they sometimes still care for it, if even temporarily.

One notable case, caught on film by animal enthusiasts and documentarians Dereck and Beverly Joubert, was aired in 2006 as part of the National Geographic Channel's "Eye of the Leopard."

The film shows how at one point in her life, the young leopard Legadema takes the risk of slaying a female baboon who had strayed too far from her troop. However, in the aftermath of the slaughter, the large predator realizes that a baby had been clinging to the downed prey.

[Credit: Wildlife Films via YouTube, full film here.]

In a stunning twist, Legadema winds up not only forgetting her fresh kill to protect the baby from nearby hyenas, but also stays the night with it, curling up with the vulnerable imp in an effort to keep it warm enough to survive the encroaching chill. Unfortunately, Legadema's efforts were in vain, as the baby does eventually pass away, but her uncharacteristic actions raised several question about motherly instincts and cross-species interaction.

The "Lion and the Lamb"

An even more startling case involves a lioness named Kamunyak, meaning "blessed one."

Discovered in the Samburu National Reserve in Northern Kenya, Kamunyak is famous for having adopted not one, but six orphaned Oryx calves over the course of her lifetime. (Scroll to read on...)

Oryx are hoofed deer-like animals that are traditionally lion prey, but Kamunyak instead was drawn to these calves, barely hunting as she followed and even protected her unusual charges from other predators.

This kind of action clearly goes above and beyond simple infant call confusion, but according to Craig Packer of the Serengeti lion project, Kamunyak's miraculous behavior may simply be a rare coping mechanism for trauma and inordinate loss.

"If by misfortune a female ends up all on her own, she lives a life of utter terror..." he explained to National Geographic.

Lone female lions, if not immediately inducted into another pride, quickly become the targets of neighboring packs, as they are seen as a competitor easily dealt with.

"What we think happened was that she actually went through quite a very sudden traumatic loss," added conservationist Sarah Douglas-Hamilton, who had contacted Packer about the unusual case. "And this clicked a switch in her head that just sparked this obsessive compulsive behavior so that when she came across this baby Oryx, instead of seeing 'food' she saw 'baby.'"

And while many may have seen Kamunyak as a biblical reference - the lion and the lamb laying down together - it may simply be an example of crossed wires taking that global acceptance of "baby" Lingel and Riede mentioned further than ever before seen.

Still, Douglas-Hamilton added that she believes that even if Kamunyak's charge had been lion cubs rather than Oryx, her behavior still would have been too obsessive and too intense to be called natural.

It's the Hormones Talking

And as romantic as a "universal love" for babies might be, Nature World News recently reported how experts from the National Primate Research Center are arguing that all mammals with some semblance of parent love are actually psychologically influenced by hormone rebalancing in the wake of a new birth or even adoption.

Hormones like oxytocin (the "love" hormone), and even testosterone help parents bond and have patience for their offspring, and develop a fondness for all things tiny, cute and cuddly - the occasional Oryx calf included.