'Bad moms' of the animal kingdom are only trying to survive

As you celebrate Mother’s Day on Sunday, be thankful that you weren’t born to a Dracula ant.

The queens of this species, known for having the fastest bite on Earth, also stand out for feeding on their babies’ blood. (See photos of animal moms and offspring.)

Many animal mothers adopt parenting styles that would make any human mom cringe. Yet there are reasons for their seemingly harsh behaviors, such as limited resources.

Here's a closer look at the motivations behind some so-called “bad moms” of the animal world.

Leopard tree iguana

Native to the Chilean Andes, this reptile mom protects her young for their first 48 hours, then abandons them in their den—along with a pile of her poop.

Not only is this pungent parting gift edible and nutritious, it also contains valuable gut microbes, says Stanley Fox, a herpetologist at Oklahoma State University.

“They pass that gut microbe from mother to offspring, and it’s in their body from then on so they can digest fruits, leaves, and flower petals.”

Poop isn’t mom’s only contribution. “The babies are very weak, so when she leaves the birth chamber, she seals up the exits so [they can’t] be preyed upon by birds,” Fox explains.

“You’d think she’s a bad mother, with no babysitter, who just locks them into their natal chamber. But they are safe inside.” (Read how animal mothers remind us of our own.)

When they get older, the juveniles simply dig themselves out.

Harp seals

Harp seal pups are mighty cute, and pups are the apple of mom’s eye—for about 12 days. During this short period, harp seal moms feed their young nonstop before abandoning them on the ice.

As cruel as it sounds, this strategy helps pups cope with frigid conditions in their North Atlantic home.

Because pups are born without blubber, their mother’s milk is 50 percent fat, allowing the 20-pound newborns to pack on five pounds a day. (For comparison, human breast milk is between 3 to 5 percent fat.) When pups reach about 80 pounds, their emaciated mothers stop nursing and retreat to the ocean to find food. (Read about long-suffering animal mothers that deserve a day, too.)

Because the young seals can’t swim and hunt until they’re eight weeks old, they must endure a dangerous period of potential starvation, predation, or drowning amid melting ice.

Twenty to 30 percent of each generation’s pups don’t survive this trial, but those that do carry strong bloodlines into the next generation.

Giant pandas

Pandas sometimes have twins, presenting a giant panda mom with a dilemma—choosing which is most likely to survive, and letting the other die.

Panda cubs are blind, hairless, and totally helpless at birth; weighing between three to five ounces, they are 1/900th the size of their mothers.

“Panda moms must hold their baby tight to maintain their body warmth and hold them to their breast to nurse. So the mother has to do everything for the baby,” says Marc Brody, founder of the nonprofit Panda Mountain and a National Geographic Explorer. (Get an exclusive look into how keepers raise a baby panda.)

“One might judge a panda ... because it chooses to abandon one child and care for another,” he adds.

But because newborn pandas are so fragile, it’s extremely hard raising just one—which is why panda mothers don’t leave their baby to eat or drink for the first few days, he says.

“As we understand a mom’s challenges—to divide your attention and try to maintain two helpless, vulnerable babies—it is reasonable and logical that pandas developed a survival instinct to select the stronger of the two newborns,” Brody explains.

Dracula ants

When Dracula is invoked to describe a method of mothering, you can be pretty sure that mom and child aren’t doing a lot of emotional bonding.

Despite having the fastest animal jaws in all of nature, Dracula ant mouths lack the ability to chew solid food. So worker ants in the colony harvest fat larvae, which they’ll tear open and drink their blood—later regurgitating the contents for the queen. (Meet the woman making ants the next big thing in biology.)

It could be worse: This ant’s brand of cannibalism is termed “nondestructive,” meaning that while the larvae get partially eaten, they do survive—with lifelong scars as testament to this unique parenting strategy.

Tasmanian devils

A Tasmanian devil baby, known as an imp, faces very long odds. These carnivorous marsupials give birth to dozens of tiny, hairless imps—up to 50 at time—but only offer four teats in their pouches.

The four imps that are quickest to crawl the three inches from the birth canal to the pouch survive. The rest become part of a shocking infant mortality rate statistic that can top 90 percent.

Mother devils are kinder to the four survivors, carrying them around, attached to their teats, for a hundred days. After that period they are often seen riding on mom’s back, and will stay with her for up to nine months. (Failure to launch: These animals stay with mom for years.)

Brown-headed cowbirds

These moms like to outsource their parenting—they lay their eggs in the nests of other birds in a behavior called brood parasitism. (Read about another famous brood parasite, the cuckoo.)

And they’re not picky: Almost 250 other species have been tricked into bringing up baby.

“We invest so much in our own offspring, we kind of have a negative view of an organism that makes somebody else take care of them,” says Brian Peer, an ornithologist at Western Illinois University.

But “when you think about the adaptations and deceptions they’ve evolved to trick hosts into caring for their young, we should be amazed.”

Peer notes that even after brown-headed cowbirds have left the nest, they continue to deceive by begging for food from birds that didn’t even raise them.