Animals

This Father’s Day, meet 6 extreme animal dads

From traveling more than a hundred miles for water to incubating up to four females’ eggs, these animals take fatherhood to a new level.Saturday, 15 June 2019

By Brian Handwerk
For male barbary macaques, carrying an infant helps build social bonds with other males. Sometimes, a macaque will carry around any available infant, even if it’s not his own.

Father knows best? Maybe so when it comes to survival of the species. But these animal dads have some seriously unconventional ideas about fatherhood often at odds with those we’ll celebrate this Father’s Day. When you look closer, though, the good reasons behind these animals’ strange styles prove there are plenty of different ways to successfully father the next generation.

Barbary macaques network using babies.

Like human dads boasting of their kids' winning goals or university acceptances, barbary macaques, primates that are native to North Africa, show off babies as a way to impress each other and build social networks. These monkeys live in troops of about 30 members, and life revolves around the babies born each spring.

During baby season, males carry the infants, even picking up little ones that aren’t their own offspring.

But it’s not because they’re helicopter parents. Instead, they’re status symbols, used to build male social networks and alliances within the troop.

“The infants also serve as a social passport, to approach other males and hang out with them,” Julia Fischer of the German Primate Center said via email. “Similar to humans having dogs: It’s much simpler to break the ice if you have a pooch.”

Any dad knows that parenting comes at a cost, and Fischer’s group discovered that infant-carrying males showed elevated levels of stress hormones. But the babies’ usefulness for building relationships among males appears to be worth the extra anxiety dads incur, Fischer says.

These marsupial males have a lethal mating process.

Antechinuses, mouse-like marsupials found in Australia, are willing to lay down their lives to become fathers.

But it’s not the rewards of parenthood that drive them—it’s a supercharged sex drive. Each male is hardwired for suicidal reproduction. The antechinus engages in two weeks of nonstop, frenzied mating in an effort to ensure his genes survive. A male will mate with as many females as he can, with each coupling lasting up to 14 hours, before he succumbs to a battered immune system, destroyed by stress hormones produced during the mating period.

“They get internal bleeding, ulcers, rampant infections, and parasites, and they lose their fur,” Diana Fisher, an ecologist at the University of Queensland, says in an email. “I think it's much more interesting than if they just exhausted themselves or didn't eat.”

The reason for the nonstop mating frenzy is that each male only has a finite amount of sperm and is therefore driven to make sure he passes on his genes before it’s all gone. “The marsupial reproductive plumbing means that they lose sperm continually in their urine, even if they do not mate,” Fisher says. “From this point there is no evolutionary reason for a male to live beyond one season.”

A male sand grouse will fly more than 100 miles to find water for his family. He soaks it up in his feathers, and when he returns to the nest, his offspring will drink from them.

Sand grouse dads make an extreme commute.

Lots of dads bring home the bacon. But for young sand grouses living in Namibia’s arid deserts, water is the essential resource that’s all too rare around their neighbourhood nesting grounds. Fortunately sand grouse fathers undertake a gruelling commute that sees the frequent flyers travel almost 125 miles each day to fill up for the family at a watering hole.

With no other way to transport water, male sand grouses settle in the pool, rocking back and forth to soak their belly feathers, which hold water in hairlike coils. Filling up can take 15 minutes, leaving them exposured to predators like swooping falcons. But it all pays off: The dads return home after a long day and are able to provide their young with few precious tablespoons of water from their feathers.

Roundworm males ensure their offspring have no competition.

You wouldn’t expect much hands-on parenting from worm fathers, and you’d be right. But roundworm dads do display some surprising behavior that’s baked into their reproduction.

When individuals of one species of roundworm pass on sperm and seminal fluid to a female, they do more than just launch the next generation—they sign her death warrant. Male fluids cause female worms to dehydrate, shrivel, and die after they give birth by hijacking and reversing genetic pathways linked to anti-ageing.

Typically the female roundworms of this intriguing species (Caenorhabditis elegans) are hermaphrodites and don’t need males to reproduce. But males of the species definitely do need a female. Consequently they find a female, mate, and inseminate her with a fatal dose. The act doesn’t harm the offspring, who need no parental care, but it does prevents the female from mating again and producing another family to compete with dad’s youngsters.

Male pipefish, like their seahorse relatives, carry eggs until they’re hatched. They have the ability to carry eggs from up to four different females to ensure they have the strongest possible offspring.

Male pipefish are always looking for bigger females.

Pregnant pipefish males—yes, males—give birth to live young from eggs that females deposit in their brood pouches. While carrying them, the fathers-to-be sacrifice their own nutrients, and even oxygen supply, to help them survive. This nurturing act has earned these straight-bodied seahorse relatives praise as devoted animal dads.

But it turns out that pregnant pipefish also have a wandering eye. If they see a more desirable female they often abort some of their eggs.

In pipefish reproduction, bigger is better: Large females tend to have more, larger, and healthier eggs. “So, we can speculate that seeing an extremely sexy female (a very, very large female) might turn the male’s head around,” Nuno Monteiro of the University of Porto, in Portugal, wrote via email. “If he stops exporting nutrients to the developing embryos while reabsorbing nutrients from abortions, he does not lose all his progeny and secures enough resources to invest in a probably more rewarding mating episode.”

Pipefish males can carry eggs from up to four different females. It’s probably his way of giving the fittest offspring the best chance to succeed in life, according to Monteiro. So while mothers and some unfortunate siblings might disagree, for those chosen survivors, the pipefish is actually a pretty devoted dad.

Blue poison dart frog males go to lengths to keep their offspring alive.

Females of this species aren’t like most other frogs. Instead of laying hundreds or thousands of eggs, they lay only about half a dozen precious ones. That may be why blue poison dart frog dads are so devoted to them—although their version of TLC may strike us as eww. Frog eggs must stay moist, and these devoted dads accomplish that by regularly urinating on them over the course of 10 days, until they hatch as tadpoles. (Meet the single dads of the animal world.)

After the eggs hatch, dad’s work isn’t over. As the primary caregiver, he must carry each tadpole, one at a time, on his back to suitable micropool of rainwater that can serve as an individual nest. Over the next few months, his offspring will develop lungs and legs and eventually become fully formed froglets.

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