10 Fascinating Animal Facts That Might Surprise You

Quck answer

1. A group of flamingos is called a flamboyance.

2. A kangaroo can’t walk backwards.

3. Sloths only defecate once a week.

4. A group of hedgehogs is called a prickle.

5. A cheetah can run up to 75 miles per hour.

6. The fingerprints of koalas are so similar to human fingerprints that they have been confused at crime scenes.

7. A group of giraffes is called a tower.

8. A snail can sleep for three years.

9. A group of rhinoceroses is called a crash.

10. Dolphins have names for each other and will respond when called by name.

Animal Facts

Did you know that some tree frogs can freeze in winter and thaw back to life in spring? This is just one of the many amazing animal facts that exist. Read on for more interesting tidbits about the animal kingdom.
iStockphoto/Thinkstock

The animal kingdom is home to a multitude of fascinating traits. For example, cheetahs can run at speeds of up to 70 mph (112 kph) [source: Enoch]. Camels can survive for up to six months without water [source: California Academy of Sciences]. And as we mentioned earlier, some tree frogs can freeze in winter and come back to life in spring [source: Roach].

While these are some of the more well-known animal talents, there are plenty of other facts that are lesser known and quite surprising. Some are even seemingly impossible, awkward, gross, or even frightening. Others are so human-like that they’ll make you laugh.

In this article, we’ve compiled a list of 10 crazy animal facts that might surprise even the most ardent animal trivia buffs. You might find yourself laughing, denying, or even squirming at some of these facts. For instance, did you know that the echidna, a spiny anteater native to Australia, has a four-headed penis? Yes, you read that correctly. Read on to discover more fascinating animal facts.

10: Echidnas Have a Four-Headed Penis

It’s hard to believe that this cute critter has a four-headed penis.
Kristian Bell/Flickr/Getty Images

Odd penises aren’t uncommon in the animal world, although to the animals themselves, they’re perfectly normal. For example, snakes have two half-penises that join together during mating [source: Medical Dictionary]. Sea slugs have disposable penises [source: Kaplan]. And cat penises are barbed [source: Dell’Amore].

However, the echidna takes the prize for the most unusual penis. This Australia-area native has a single shaft with four heads, each capable of ejaculation. Only two of the heads function at any given time, though, because the female echidna has only two vaginas. During copulation, one side of the penis is inactive, with its two heads retracted, while the other side is ready to fertilize the female’s eggs. The male echidna then switches sides and repeats the process [source: Cooke].

The reason for the four heads is not entirely clear, but experts think it might have something to do with mating competition. Female echidnas may mate with 10 or more males during mating season, so having four ejaculation sources probably increases the odds of passing on genes [source: Cooke].

9: Hens Can Transform into Roosters

Was this rooster originally a hen?
iStockphoto/Thinkstock

Spontaneous sex changes are rare in the animal world, but they do happen. For example, clownfish change from male to female as part of the mating process. However, the situation is different for hens, as their sex change is not beneficial to the species [source: Melina].

It all starts with hen anatomy. A female chicken has one ovary and one inactive gonad, a remnant of early chicken development when sex genes haven’t yet activated. A gonad can become an ovary, a testicle, or a combination of the two (ovotestis), but once those genes go the female route, the other gonad remains inactive [source: Melina].

If a cyst or tumor damages a hen’s ovary, it can cause a sex change. The gonad will develop into a testicle or an ovotestis instead of an ovary, leading to the release of androgens, a male sex hormone. This results in the typical hen-to-rooster transition, where the hen stops laying eggs, gains weight, and develops male physical traits such as dark feathers, a rooster’s comb, and wattles. However, this change only occurs in females. A rooster-to-hen conversion has never been documented [source: Melina].

8: Raccoons May Wash Food Before Eating

Despite being known as urban scavengers, raccoons will wash their food if given the opportunity. A raccoon will dunk its food in water, rotating it repeatedly before consuming it. Researchers have found that raccoons will even dunk their food in the air if there is no water available. This behavior may not be for cleanliness purposes but rather to intensify the tactile aspects of the meal, as raccoons have sensitive fingers and may enjoy the feeling of the ritual [source: Welshans].

7: A Bald Eagle Nest Can Weigh 2 Tons

Bald eagles build nests that break trees and can weigh up to 2.2 tons. A typical bald eagle nest is up to 5 feet in diameter and 6 feet deep. However, the largest nest ever found had a weight of over 2.2 tons, a diameter of 9.6 feet, and a depth of 20 feet. Another nest discovered in Ohio in the 1920s was 8.5 feet across, 12 feet deep, and weighed around 2 tons [source: Guinness World Records, Ohio Dept. of Natural Resources].

Bald eagles slowly build massive nests made of twigs, branches, moss, feathers and other materials, which they reuse year after year for several decades. The Ohio Department of Natural Resources estimates that a pair of bald eagles, or possibly more over time, had been building and living in a 2-ton nest in Ohio for about 35 years before it collapsed.

6: A Fruit Fly’s Sperm Is Much Longer Than a Man’s

The longest sperm in the animal kingdom belongs to the Drosophila bifurca fruit fly. The fly, which is about 3 millimeters long, produces sperm that measures approximately 58 millimeters long, coiled up in its tiny body. This sperm is 1,000 times longer than a human’s, which measures about 0.06 millimeters in length. Scientists believe that the level of “sperm competition” in a species corresponds with the species’ sperm length. Humans have low sperm competition, while fruit flies’ females store sperm from multiple mates. The sperm that can beat the previously stored sperm has the best chance of fertilizing the egg.

5: Leeches Have 300 Teeth

Despite their boneless, wormy form, leeches have three sets of teeth with a total of 300 razor-sharp, highly effective cutting instruments. These teeth are used to make a surgical incision that initiates blood flow and allows them to suck blood. Leeches are increasingly used in modern medicine to establish blood flow to re-attached body parts. When placed on the skin, a leech grabs on with its “mouth” that contains three separate jaws with 100 teeth each. The jaws and teeth make separate incisions, forming a cut that allows blood flow. In between the teeth, there are ducts that release an anticoagulant to keep the blood flowing quickly.

Fortunately for those undergoing leech therapy, the ducts in leeches also release an anesthetic, meaning the process is usually painless. However, unfortunately for patients, these ducts don’t release anything pleasant [sources: Е epitka, Lubrano].

4: Butterflies Use Their Feet to Taste

Butterflies use their feet to determine if a plant is toxic before laying their eggs on it.
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Yes, you read that correctly. Butterflies have receptors on their legs that are 200 times stronger than human taste buds [source: Encyclopedia Britannica, Clare]. These receptors help butterflies test areas for toxins or other harmful elements that could harm their offspring [source: Encyclopedia Britannica].

Adult butterflies don’t eat, only drink, but their caterpillars eat constantly [source: San Diego Zoo]. After hatching, they feed on the leaves of the plant on which they were born. Since some plants produce toxins as a defense mechanism, choosing the wrong leaves can prove catastrophic [sources: San Diego Zoo, UC Irvine], which is where the mother’s feet come in.

When a female butterfly lands on a leaf, she uses her feet to taste the plant and determine whether it is safe for her caterpillars. If she detects nothing harmful, she knows she can safely raise her offspring there.

3: A Green Anaconda Could Swallow a Person Whole

At 30 feet long and weighing up to 550 pounds, the green anaconda is the heaviest snake in the world.
Jonathan Wiggs/The Boston Globe via Getty Images

Not many people would choose to get close to an anaconda. The green anaconda is the heaviest snake in the world, growing up to 30 feet (9 meters) long, 1 foot (0.3 meters) in diameter, and weighing up to 550 pounds (250 kilograms) [source: National Geographic].

However, green anacondas rarely attack humans, and there are no confirmed reports of humans being eaten by the snake, possibly due to their limited presence in areas where people live [source: Zoo Atlanta]. They are found primarily in the secluded waters of South American rainforests [source: National Geographic].

Despite this, they can eat humans, as their usual prey includes fish, wild pigs, adult white-tailed deer, caimans (similar to alligators), and the occasional jaguar. Caimans can grow up to 15 feet (4.5 meters) long [source: A-Z Animals], jaguars can weigh up to 350 pounds (159 kilograms) [source: A-Z Animals], and white-tailed deer grow up to 7 to 8 feet (2.1-2.4 meters) and weigh up to 300 pounds (136 kilograms) [source: National Geographic]. In comparison, the average man is 5 feet 9 inches (1.7 meters) tall and weighs 195 pounds (88 kilograms) [source: Statistic Brain].

To swallow larger animals, the snake wraps around the prey to crush and/or suffocate it before slowly swallowing it headfirst. It widens its jaws, which are connected by stretchy ligaments, before grabbing the prey with its teeth. After a large meal, an anaconda may not eat for months [sources: National Geographic, Rivas].

However, not all large prey is suitable for them, as one anaconda was filmed regurgitating an entire cow.

2: Dachshunds Are More Aggressive Than Pit Bulls

Despite common belief, dachshunds are more aggressive than pit bulls.
iStockphoto/Thinkstock

Many people believe that pit bulls are naturally aggressive. However, pit bull attacks on humans often make the news due to their tragic consequences.

According to a 2008 study by the University of Pennsylvania that analyzed thousands of dogs from 33 breeds, pit bulls were not the most aggressive dogs towards humans. Dachshunds had a higher percentage of bite attacks against strangers and owners compared to pit bulls, with Chihuahuas, Jack Russells, and beagles also beating out pit bulls for aggression towards people. However, both dachshunds and pit bulls scored high in aggressiveness towards other dogs. Despite this, African wild dogs, which live in packs in sub-Saharan Africa, practice humane behaviors such as caring for their elderly, sick, or otherwise fragile pack members. After a kill, young and healthy dogs will return to the den and feed the ill, old, or young members by regurgitating some of the kill. This behavior challenges the notion that only humans are capable of empathy and altruism towards others.

Is modern medicine using leeches?
How do dogs function?
How do snakes work?
Why is biodiversity important?

Sources

3D Science. “Sperm and Ova (Spermatozoa and Oocytes) Human Reproductive Cells.” (August 29, 2013) http://www.3dscience.com/Resources/Reproductive_Cells.php
A-Z Animals. “Jaguar.” (August 31, 2013) http://a-z-animals.com/animals/jaguar/
Animal Fact Guide. “Green Anaconda.” (August 29, 2013) http://www.animalfactguide.com/animal-facts/green-anaconda/
Animal Planet. “Caiman.” (August 29, 2013) http://animal.discovery.com/reptiles/caiman-info.htm
Birds.com. “Laysan Albatross (Diomedea immutabilis).” (August 29, 2013) http://www.birds.com/species/k-o/laysan-albatross/
BBC. “The Elephant’s Guide to Sex: Does Size Matter?” March 2007. (August 29, 2013) http://www.bbc.co.uk/sn/tvradio/programmes/horizon/broadband/tx/elephant/sizequiz/index_textonly.shtml
California Academy of Sciences. “Tour the Exhibit: Camels can cross deserts.” (September 5, 2013) http://www.calacademy.org/exhibits/africa/exhibit/sahara/tuareg/3.htm
Clare, Horatio. “Fragile, beautiful, endangered вЂ“ why butterflies are worth saving.” The Telegraph. July 19, 2013. (August 31, 2013) http://www.telegraph.co.uk/earth/wildlife/10190916/Fragile-beautiful-endangered-why-butterflies-are-worth-saving.html
Cooke, Lucy. “The Tasmanian Echidna’s Four-headed Penis.” National Geographic. July 3, 2012. (August 26, 2013) http://tvblogs.nationalgeographic.com/2012/07/03/the-tasmanian-echidnas-four-headed-penis/
Dell’Amore, Christine. “Why Human Penises Lost Their Spines.” National Geographic News. March 9, 2011. (August 27, 2013) http://news.nationalgeographic.com/news/2011/03/110309-humans-men-penises-spines-dna-genome-science/
Dobson, Roger. “Sausage Dogs are the Most Aggressive Dogs.” The Telegraph. July 5, 2008. (August 31, 2013) http://www.telegraph.co.uk/news/newstopics/howaboutthat/2254479/Sausage-dogs-are-the-most-aggressive-dogs.html
Duffy, Deborah L, Yuying Hsu, James A. Serpell. “Breed differences in canine aggression.” Applied Animal Behaviour Science, Volume 114, Issues 3вЂ“4, 1 December 2008, Pages 441вЂ“460. Available at http://www.sciencedirect.com/science/article/pii/S0168159108001147. Accessed August 30, 2013.
Encyclopaedia Britannica. “Specialized chemosensory structures.” (August 29, 2013) http://www.britannica.com/EBchecked/topic/109023/chemoreception/279480/Specialized-chemosensory-structures#ref1020083
Enoch, Nick. “You won’t see me for dust!” The Daily Mail. May 8, 2013. (September 5, 2013) http://www.dailymail.co.uk/news/article-2321319/Cheetah-slow-motion-Incredible-shots-capture-cat-accelerating-70mph.html
Guinness World Records. “Largest Bird’s Nest.” (August 26, 2013) http://www.guinnessworldrecords.com/records-10000/largest-birds-nest/
LaFlamme, Brooke A. “Size matters for fruit flies.” Molecular Love. June 16, 2011. (August 29, 2013) http://nittygrittyscience.com/2011/06/16/size-matters-for-fruit-flies/
Leary, Warren E. “When it Comes to Giant Sperm, This Tiny Fruit Fly is a Whale.” The New York Times. May 11, 1995. (August 29, 2013) http://www.nytimes.com/1995/05/11/us/when-it-comes-to-giant-sperm-this-tiny-fruit-fly-is-a-whale.html
Lindemann, Charles. “Dr. Lindemann’s Fun Sperm Facts!” Oakland University. (August 29, 2013) http://www2.oakland.edu/biology/lindemann/spermfacts.htm
Lubrano, Alfred. “Useful little suckers. Scalpel, sponge, and leech.” The Inquirer/Philly.com. July 25, 2001. (August 29, 2013) http://articles.philly.com/2001-07-25/news/25314895_1_medicinal-leeches-leeches-usa-cure-for-various-ailments
Medical Dictionary. “Hemipenes.” (August 27, 2013) http://medical-dictionary.thefreedictionary.com/Hemipenis
Melina, Remy. “Sex-Change Chicken: Gertie the Hen Becomes Bertie the Cockerel.” Live Science. March 31, 2011. (August 26, 2013) http://www.livescience.com/13514-sex-change-chicken-gertie-hen-bertie-cockerel.html
National Geographic. “African Wild Dog.” (August 31, 2013) http://animals.nationalgeographic.com/animals/mammals/african-hunting-dog/
National Geographic. “Green Anaconda.” (August 29, 2013) http://animals.nationalgeographic.com/animals/reptiles/green-anaconda/
National Geographic. “White-Tailed Deer.” (August 31, 2013) http://animals.nationalgeographic.com/animals/mammals/white-tailed-deer/
Ohio Department of Natural Resources. “Bald Eagles Soar in Ohio’s Skies.” (August 26, 2013) http://www.dnr.state.oh.us/Home/ExperienceWildlifeSubHomePage/kidspagesplaceholder/kidsbaldeagle/tabid/6017/Default.aspx
Rivas, J. A, 1999. “Predatory attacks of green anacondas (Eunectes murinus) on adult human beings.” Herpetological Natural History. 6(2): 158-160. Available at: http://www.anacondas.org/strike.htm. Accessed: September 1, 2013.
Roach, John. “Antifreeze-Like Blood Lets Frogs Freeze and Thaw With Winter’s Whims.” National Geographic News. February 20, 2007. (August 24, 2013) http://news.nationalgeographic.com/news/2007/02/070220-frog-antifreeze.html
San

The following is a list of sources related to various animals and topics: Diego Zoo’s webpage on butterflies, San Diego Zoo’s page on bald eagles, a poster on leech teeth presented at a conference, statistics about the human body, a study on taste sensor genes in female butterflies conducted by the University of California at Irvine, Vancouver Aquarium’s fact sheet on green anacondas, an article about raccoons and their food-washing habits from The Sun Gazette, and the Wildlife Conservation Society’s information page on African wild dogs. Additionally, Zoo Atlanta’s website also provides information about green anacondas.

FAQ

1. What animal has the largest eyes in the world?

The animal with the largest eyes in the world is the giant squid. Their eyes can be as big as basketballs and are the largest eyes of any living creature. This is because they live in the deepest parts of the ocean where there is little to no light, so their large eyes help them see in the dark.

2. Can an octopus really fit through a tiny hole?

Yes, an octopus can fit through a tiny hole. Octopuses are highly intelligent creatures and are able to contort their bodies to fit through openings smaller than their heads. They are also able to change the texture and color of their skin to blend in with their surroundings, making it easier for them to sneak through tight spaces undetected.

3. Which animal has the strongest bite?

The animal with the strongest bite is the saltwater crocodile. Their bite is stronger than that of any other animal and is powerful enough to crush a human skull. This is because they need to be able to catch and kill their prey, which can include animals as large as water buffalo.

4. Can a kangaroo really jump over a car?

While it may seem like a myth, kangaroos are actually able to jump over cars. They are incredible jumpers and can jump up to three times their own body length in one bound. This means that they are able to jump over objects as tall as they are, which can include cars.

5. What is the deadliest animal in the world?

The deadliest animal in the world is the mosquito. While they may seem harmless, mosquitoes are responsible for more deaths than any other animal on the planet. This is because they are able to transmit diseases such as malaria, dengue fever, and Zika virus to humans through their bites.