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11 Animals that are Super Small at Birth

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Baby blue whales are a ton of fun—literally. The giant newborns typically tip the scales at a jaw-dropping three tons at birth. (If you want to visualize how that stacks up to a full-grown whale, it’s about the same size as an adult whale’s tongue.)

Whale babies easily dwarf their competition in the big baby world, but that doesn’t mean they're any more charming or special than even the smallest of newborns. Pound for pound (or ounce for ounce, as the case may be), the animal kingdom’s littlest newbies are still pretty wonderful in their own way.

1. Kangaroos

The marsupial birthing process is positively insane, but it’s also one of the most miraculous in the wild world. Baby kangaroos—you know them as joeys—only gestate in their mother’s womb for about a month. After that period, they are technically born, yet they emerge blind, hairless, and only about an inch in length before crawling into their mother’s pouch (called a marsupium) where they finish developing and growing for up to 400 days. After that time, they pop out of the pouch and look like what we’d expect a joey to look like, all furry and cute, even though they first entered the world looking like a piece of bubble gum.

2. Honey possum

Elsewhere in the marsupial world, the honey possum is believed to be the smallest mammal at birth. Baby honey possums only weigh about 0.005 grams when they are born, eventually completing their gestation inside their mother’s pouch to reach a hefty 2.5 grams by the time they’re ready to venture out on their own.

3. Pygmy seahorse

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The pygmy seahorse remains pregnant for approximately 11 days, after which the offspring are born by way of the male contorting his body in order to eject the tiny babies—each between 7 and 12 millimeters in size—from his pouch, sending them on to embark on their own adult lives. But poor papa doesn’t get much time to recover from his postpartum depression; it is not uncommon for the female to gift the male with another clutch of eggs as soon as 30 minutes after he’s expelled a brood.

4. Pygmy mouse lemur

Photo courtesy of Joachim S Muller, used under Creative Commons license

Another pygmy baby, the pygmy mouse lemur, also barely makes a dent on the birthing scales. Already the world’s smallest primate, pygmy mouse lemurs only grow to weigh about an ounce when they are adults, so it should come as no surprise that they are born only weighing about .45 gram.

5. Pygmy marmoset

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Pygmy marmosets are the world’s smallest monkey species, so their young are also quite wee. At birth, pygmy marmosets weigh about 15 grams each, and are typically born in pairs (though it’s possible for triplets or just a single birth to occur).

6. Etruscan shrew

The Etruscan shrew has the distinction of being the world’s smallest mammal by mass only (if we’re measuring by skull size, the bumblebee bat is the smallest). Adult Etruscan shrews only grow to about 4 centimeters in length (this doesn’t include their tiny tails, which can be as long as 3 centimeters). Baby shrews gestate for about four weeks, and are born in litters that can be as small as two cubs and as large as six. When they enter the world, they only weigh about 0.2 grams, and they can grow to be as large as 2.5 grams in maturity.

7. Bee hummingbird

Photo courtesy of Carol Foil, under Creatve Commons liscense

The bee hummingbird is the smallest bird in the world, so its young are appropriately tiny. As adults, they weigh somewhere around 2 grams (about the same as a penny), and babies hatch from eggs roughly the size of coffee beans.

8. Brazilian gold frog

Photo courtesy of Farrukh, under Creative Commons liscense

The Brazilian gold frog is the second smallest frog in the Southern Hemisphere, with adults clocking in at 9.8 millimeters in body length (not counting splayed-out legs). At hatching, baby gold frogs weigh a fraction of their adult counterparts, though a precise amount is currently unknown.

9. Pudu

Although the southern pudu is the more distinct of the pudu pair, it’s the northern pudu that clocks in as the world’s smallest deer. As adults, they stand about 13 inches tall, and rarely weigh more than 13 pounds. Baby northern pudus usually weigh in the 23 to 35 ounce range, and it’s extremely rare that infant pudus that weigh less than 21 ounces live.

10. Paedocypris carp

Maurice Kottelat/Woman's Day 

Believed to be the world’s smallest fish species, the Paedocypris carp only grows to about 7.9 millimeters. Much like the tiny gold frog, it’s nearly impossible to guess how big the little carps are when they hatch, but they’re expected to also be the smallest fish babies on the planet.

11. Pink fairy armadillo

Photo courtesy of Cliff, under Creative Commons license

The pink fairy armadillo, an Argentinean native, is the smallest kind of armadillo, special not just for its tiny size but also its puffy fur. Adult pink fairies are about 4.5 inches long (not including their tails), and they are all prodigious diggers. Baby pink fairies are born weighing about 3 or so grams before growing into a chipmunk-like size.

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Why Tiny 'Hedgehog Highways' Are Popping Up Around London
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Hedgehogs as pets have gained popularity in recent years, but in many parts of the world, they're still wild animals. That includes London, where close to a million of the creatures roam streets, parks, and gardens, seeking out wood and vegetation to take refuge in. Now, Atlas Obscura reports that animal activists are transforming the city into a more hospitable environment for hedgehogs.

Barnes Hedgehogs, a group founded by Michel Birkenwald in the London neighborhood of Barnes four years ago, is responsible for drilling tiny "hedgehog highways" through walls around London. The passages are just wide enough for the animals to climb through, making it easier for them to travel from one green space to the next.

London's wild hedgehog population has seen a sharp decline in recent decades. Though it's hard to pin down accurate numbers for the elusive animals, surveys have shown that the British population has dwindled by tens of millions since the 1950s. This is due to factors like human development and habitat destruction by farmers who aren't fond of the unattractive shrubs, hedges, and dead wood that hedgehogs use as their homes.

When such environments are left to grow, they can still be hard for hedgehogs to access. Carving hedgehog highways through the stone partitions and wooden fences bordering parks and gardens is one way Barnes Hedgehogs is making life in the big city a little easier for its most prickly residents.

[h/t Atlas Obscura]

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Stones, Bones, and Wrecks
New Program Trains Dogs to Sniff Out Art Smugglers
Penn Vet Working Dog Center
Penn Vet Working Dog Center

Soon, the dogs you see sniffing out contraband at airports may not be searching for drugs or smuggled Spanish ham. They might be looking for stolen treasures.

K-9 Artifact Finders, a new collaboration between New Hampshire-based cultural heritage law firm Red Arch and the University of Pennsylvania, is training dogs to root out stolen antiquities looted from archaeological sites and museums. The dogs would be stopping them at borders before the items can be sold elsewhere on the black market.

The illegal antiquities trade nets more than $3 billion per year around the world, and trafficking hits countries dealing with ongoing conflict, like Syria and Iraq today, particularly hard. By one estimate, around half a million artifacts were stolen from museums and archaeological sites throughout Iraq between 2003 and 2005 alone. (Famously, the craft-supply chain Hobby Lobby was fined $3 million in 2017 for buying thousands of ancient artifacts looted from Iraq.) In Syria, the Islamic State has been known to loot and sell ancient artifacts including statues, jewelry, and art to fund its operations.

But the problem spans across the world. Between 2007 and 2016, U.S. Customs and Border Control discovered more than 7800 cultural artifacts in the U.S. looted from 30 different countries.

A yellow Lab sniffs a metal cage designed to train dogs on scent detection.
Penn Vet Working Dog Center

K-9 Artifact Finders is the brainchild of Rick St. Hilaire, the executive director of Red Arch. His non-profit firm researches cultural heritage property law and preservation policy, including studying archaeological site looting and antiquities trafficking. Back in 2015, St. Hilaire was reading an article about a working dog trained to sniff out electronics that was able to find USB drives, SD cards, and other data storage devices. He wondered, if dogs could be trained to identify the scents of inorganic materials that make up electronics, could they be trained to sniff out ancient pottery?

To find out, St. Hilaire tells Mental Floss, he contacted the Penn Vet Working Dog Center, a research and training center for detection dogs. In December 2017, Red Arch, the Working Dog Center, and the Penn Museum (which is providing the artifacts to train the dogs) launched K-9 Artifact Finders, and in late January 2018, the five dogs selected for the project began their training, starting with learning the distinct smell of ancient pottery.

“Our theory is, it is a porous material that’s going to have a lot more odor than, say, a metal,” says Cindy Otto, the executive director of the Penn Vet Working Dog Center and the project’s principal investigator.

As you might imagine, museum curators may not be keen on exposing fragile ancient materials to four Labrador retrievers and a German shepherd, and the Working Dog Center didn’t want to take any risks with the Penn Museum’s priceless artifacts. So instead of letting the dogs have free rein to sniff the materials themselves, the project is using cotton balls. The researchers seal the artifacts (broken shards of Syrian pottery) in airtight bags with a cotton ball for 72 hours, then ask the dogs to find the cotton balls in the lab. They’re being trained to disregard the smell of the cotton ball itself, the smell of the bag it was stored in, and ideally, the smell of modern-day pottery, eventually being able to zero in on the smell that distinguishes ancient pottery specifically.

A dog looks out over the metal "pinhweel" training mechanism.
Penn Vet Working Dog Center

“The dogs are responding well,” Otto tells Mental Floss, explaining that the training program is at the stage of "exposing them to the odor and having them recognize it.”

The dogs involved in the project were chosen for their calm-but-curious demeanors and sensitive noses (one also works as a drug-detection dog when she’s not training on pottery). They had to be motivated enough to want to hunt down the cotton balls, but not aggressive or easily distracted.

Right now, the dogs train three days a week, and will continue to work on their pottery-detection skills for the first stage of the project, which the researchers expect will last for the next nine months. Depending on how the first phase of the training goes, the researchers hope to be able to then take the dogs out into the field to see if they can find the odor of ancient pottery in real-life situations, like in suitcases, rather than in a laboratory setting. Eventually, they also hope to train the dogs on other types of objects, and perhaps even pinpoint the chemical signatures that make artifacts smell distinct.

Pottery-sniffing dogs won’t be showing up at airport customs or on shipping docks soon, but one day, they could be as common as drug-sniffing canines. If dogs can detect low blood sugar or find a tiny USB drive hidden in a house, surely they can figure out if you’re smuggling a sculpture made thousands of years ago in your suitcase.

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