So much of our lives are oriented towards other humans instead of animals. But learning animal facts can help people understand the species with whom we share this world. Understanding can be followed by respect, as well as compassion for the plight many animals face today. Understanding animals can result in people’s behavior being modified, and greater action being taken to reduce harm to animals.
Below are some facts about animals—and a couple of popular myths, debunked.
What Are the Six Types of Animals?
There are six categories of animals on planet Earth. Human beings belong to the mammalian family, which is characterized by a warm-blooded metabolism, having some form of fur or hair, and giving birth to live young who are then fed milk.
Next up are birds, who are also warm-blooded, but are covered in feathers rather than hair, which help many species to take flight. Evolved from dinosaurs, birds are highly vocal and give birth to eggs.
Reptiles are cold-blooded and scale-covered and are the group that roamed the earth as dinosaurs for hundreds of millions of years. There are four types of reptiles: lizards, turtles and tortoises, snakes, and crocodiles, and alligators. All lay leathery eggs and rely on the sun to provide warmth.
Amphibians are semi-aquatic animals who must always remain moist, either by sitting in a body of water such as a pond or lake, or retaining moisture in their bodies, as toads do.
Fish generally always remain in the water, whether fresh, brackish, or salt. Instead of lungs, fish breathe through gills, enabling them to absorb oxygen contained in the water itself. Note that some animals who spend their lives in the ocean—such as whales and dolphins—are not fish, but mammals, since they breathe air with lungs and provide milk for their young.
Last but not least are invertebrates, which means animals who lack backbones and internal skeletons. This is a highly varied category of animal. It includes insects (whose skeletons are on the outside of their bodies), arthropods (those with a segmented exoskeleton, such as crustaceans), worms, sea animals like octopuses, and sponges, and others.
How Many Animals Are There in the World?
While it’s extremely difficult to say how many animals are alive in the world at any given moment, there are other more concrete estimates that can help paint the picture of the wild world. Altogether, there are approximately 1.2 million known species of animals—though this number may be far greater since scientists estimate there are thousands of species that remain undiscovered. Out of the known species, roughly 5000 are mammals, close to 10,000 are birds, and nearly 1 million are insects.
What Is the Most Popular Wild Animal?
It depends on what is meant by the word “popular.” Going strictly by numbers of living animals, those species who are farmed would be most popular, with chickens topping this list: in 2019 there were an estimated 25.9 billion chickens in the world, all being raised for human consumption (for both meat and eggs).
If popularity denotes charisma, the answer becomes quite different. One study analyzed twenty animals considered the most beautiful, impressive, or otherwise valued, with species such as pandas, polar bears, and elephants making the list. Coming out ahead of all others, though, is—drumroll please… the tiger.
What Is the Most Dangerous Animal in the World?
Sharks and grizzly bears are species that easily come to mind when imagining the world’s most dangerous animals. But this is a serious misconception.
By sheer numbers, no other animal in the world is more deadly than Homo sapiens. When industrial animal agriculture (including fishing), habitat destruction, and pollution are all taken into account, humans emerge as the most dangerous animal to other species. And we are deadly to our own species as well, with homicides making up roughly half a million deaths per year. The only animal that kills more humans than humans do is the humble mosquito, due to the transmission of diseases such as malaria.
How Many Animals Are Killed Each Day?
Some 3 billion animals are thought to be killed for food each day, most of them at sea.
If this number seems mind-bogglingly excessive, that’s because it is. Of course, it’s natural for many animals—including humans—to be born and die each day. Life is sustained through the death of others, be they plant or animals others. But human beings—particularly those in wealthy nations—kill many more animals than is necessary for survival.
The number of land animals killed for food annually is over 70 billion (check out more of our stats and charts here). Sea animals are even more difficult to count, since many statistics on fisheries are given by the ton, rather than counting individuals. One study put the number at around 2 trillion per year—and this excludes a number of other causes of death including bycatch, which can account for nearly half the total catch of some species. Add to this about 100 million animals killed per year in laboratories, on fur farms, and through hunting, as well as those who die from plastic pollution in the oceans, and the numbers become even more unfathomable.
Unfortunately, this data illustrates that the predominant relationship between humans and animals is that of killing.
Below are amazing facts about animals and birds. These unbelievable animal facts are actually true. We’ve also included a couple of common myths you may have heard, and debunked them based on the most current science.
A Cow Gives Nearly 200,000 Glasses of Milk in a Lifetime
When it comes to cows who are confined within the industrial agricultural food system, the word “gives” is a euphemism. Mothers are forcibly impregnated, then separated from their babies, sometimes only hours after birth. The baby is prevented from nursing, enabling farmers to harvest milk for humans instead. Calves frequently wind up in the veal industry, where they are killed at a very young age.
While a single cow can be made to produce 200,000 glasses of milk in her lifetime, the truth is that humans don’t need to drink a single glass to remain healthy.
Pigeons Can Do Math
Numerical problems can inspire fear and anxiety in many of us (the author included), but some species tackle these things handily. A study in 2011 determined pigeons’ ability to reason using abstract rules about math—with skill levels on a par with monkeys.
Giraffes Can Hum, but Only at Night
It was long suspected that giraffes made no noise because people listening to them—both in the wild and captive environments—hadn’t heard them make any vocalizations. Scientists previously assumed that the characteristic long necks of these ruminants contained vocal cords that were essentially useless, despite being fully developed and apparently functional. Recently, however, it was discovered that giraffes do make vocalizations—they hum, and only at night. Take a listen here.
Wild Chimps Like to Drink
There’s nothing wrong with enjoying a nice fruity cocktail every so often—even the chimps are doing it! Fermented sap from a palm tree is the preference of one group of chimps, who were observed sopping up this naturally occurring bevy using leaf sponges.
Kangaroos Do, in Fact, Fart
It was once believed that kangaroos didn’t produce methane, a greenhouse gas commonly found in the flatulence of herbivores (and a major driver of climate change). This is how the rumor got going that kangaroos can’t fart. However, after locking a group into a sealed room, feeding them a variety of food types, and measuring the resulting air quality, it was found that they do, in fact, fart. Hopefully, they were soon released into the fresh air after the study concluded.
Koalas Sleep up to 22 Hours a Day
Because koalas’ primary source of food—the eucalyptus tree—is toxic, their digestive systems need to work overtime to break the toxins down. This process is energy-consuming and is why they sleep for 18 to 22 hours per day. Maybe eating toxic food isn’t the best approach to leading a lively life, but a life of sleeping doesn’t sound too bad either.
Elephants Are the Only Animal That Can’t Jump
It’s true that adult elephants can’t jump, but they are far from being the only land animal lacking this ability. The portly rhino and mostly aquatic hippo don’t jump either. Jumping tends to be a mechanism for evading predators, and when you’re big enough, the need to run away becomes unnecessary. It should be noted that young elephants can jump, as they are far more susceptible to predation than adults.
Octopuses Can Taste With Their Arms
The suckers lining the undersides of an octopus’s arm are for more than just gripping. These structures are similar to taste buds on human tongues, only these enable both taste and smell. Each arm is filled with neurons, so these cephalopods are also thinking with their arms, too.
Sloths Can Take up to a Month to Completely Digest a Single Leaf
Everything about sloths is slow—including their digestion. Because a sloth’s diet consists largely of toxic leaves which are difficult to digest—with a single leaf sometimes taking 30 days there is little energy left over for fast movement. But who needs it when you’ve got a coat covered in algae to camouflage you from predators?
Squirrels Will Adopt Orphans
Many species of the animal kingdom aside from humans adopt youngsters of their own kind, and sometimes even of different species. What makes this behavior notable in squirrels is that they tend to be asocial—meaning that they live in relative isolation from one another, as opposed to social species such as lions or elk. Red squirrels were observed adopting young particularly if they were related.
Butterflies Taste With Their Feet
Imagine being able to taste the floor. This is something most of us would find unappetizing—but if you spent your days stepping on fragrant flower petals, it might be a different story. And in this case, you would be a butterfly, since these insects have receptors on their feet and legs similar to that of human taste buds.
Squirrels Plant Thousands of New Trees Each Year
According to one study, squirrels fail to recover up to 74 percent of the acorns they store. Many of these are buried in the ground, which one researcher points out is “practically planting” baby trees.
The question these studies haven’t answered so far is whether squirrels are intentionally planting trees, rather than forgetting where they stored nuts. Since squirrels have an interest in the growth of more trees, which provide them with more food and shelter, the idea may not be that far-fetched.
Cows Have Best Friends
An experiment was conducted placing together cows who’d known one another—AKA, their best friend—and those who were strangers. When placed with their best friends, the cow’s heart rates were significantly lower, as were cortisol levels (lower cortisol indicates lower stress). Both of these indicators shot up when cow friends were separated.
Sadly this research was conducted with an eye towards improving milk yields on farms. Not measured were stress levels when newborn calves are separated from their mothers.
Gorillas Can Catch Human Colds and Other Illnesses
Diseases frequently pass between humans and animals. Zoonotic disease transmission occurs when a disease passes from animals to humans, as with the novel coronavirus which caused the global pandemic of 2020. Reverse zoonosis occurs when diseases pass from humans to animals. Gorillas are susceptible to reverse zoonosis, particularly respiratory infections. In Africa, wild gorillas are exposed to these diseases through the ecotourism industry, posing significant risks to highly endangered populations.
The Bat Is the Only Mammal That Can Fly
Although more similar in appearance and behavior to birds, bats actually have a lot in common with human beings. Both species are mammals, since bats give birth to live young and wean them on milk, and are covered with hair rather than feathers or scales. Where bats are exceptional is their ability to fly under their own power, which no other mammal in the world possesses.
Do Your Part
Planet earth is home to so many incredible species of animals, each with their own unique perspectives on the world. Now that you know more about those with whom we share this planet, hopefully, you will do your part to reduce suffering and support initiatives that aim to increase respect and protection for animals everywhere.
Sentient Media editorial team.