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Animals
- All About Aardvarks – Lesson
- All About Aardvarks – Quiz
- Babirusa – What a Pig! – Lesson
- Babirusa – What a Pig! – Quiz
- The Chimpanzee – The Nearly Human Primate – Lesson
- The Chimpanzee – The Nearly Human Primate – Quiz
- The Donkey – The Intelligent Yet Stubborn Animal – Lesson
- The Donkey – The Intelligent Yet Stubborn Animal – Quiz
- Electric Eels – Shocking Details – Lesson
- Electric Eels – Shocking Details – Quiz
- Ferrets – Playful, Fun-Loving Animals – Lesson
- Ferrets – Playful, Fun-Loving Animals – Quiz
- Giraffe – The Tallest Living Land Animal – Lesson
- Giraffe – The Tallest Living Land Animal – Quiz
- The Hedgehog – Lesson
- The Hedgehog – Quiz
- Iguanas – The “Chickens of the Tree” – Lesson
- Iguanas – The “Chickens of the Tree” – Quiz
- Jaguar – The Largest Cat on the American Continent – Lesson
- Jaguar – The Largest Cat on the American Continent – Quiz
- Koala – Not Koala Bear – Lesson
- Koala – Not Koala Bear – Quiz
- Llamas – The Alpaca’s Kind and Charismatic Cousins – Lesson
- Llamas – The Alpaca’s Kind and Charismatic Cousins – Quiz
- Macaws – The Intelligent, Brightly Colored Birds – Lesson
- Macaws – The Intelligent, Brightly Colored Birds – Quiz
- The Odd-Looking Narwhal – Lesson
- The Odd-Looking Narwhal – Quiz
- Otters – Playful Mammals and Great Swimmers- Lesson
- Otters – Playful Mammals and Great Swimmers – Quiz
- Polar Bears – The Largest Bear of Them All – Lesson
- Polar Bears – The Largest Bear of Them All – Quiz
- Quails – The Nearly Flightless Birds – Lesson
- Quails – The Nearly Flightless Birds – Quiz
- Rattlesnakes – The Venomous Reptiles – Lesson
- Rattlesnakes – The Venomous Reptiles – Quiz
- Sloths – Slow Is the Name of Their Game – Lesson
- Sloths – Slow Is the Name of Their Game – Quiz
- Tasmanian Devils – Catch One in a Looney Tunes Cartoon – Lesson
- Tasmanian Devils – Catch One in a Looney Tunes Cartoon – Quiz
- Gobbling Up Turkey on Thanksgiving Day – Lesson
- Gobbling Up Turkey on Thanksgiving Day – Quiz
- Deer – One of the Most Successful Animal Breeds in the World – Lesson
- Deer – One of the Most Successful Animal Breeds in the World – Quiz
- Wolves – Apex Predators – Lesson
- Wolves – Apex Predators – Quiz
- Yellowthroat – A Curious Songbird on the Ground and in the Air – Lesson
- Yellowthroat – A Curious Songbird on the Ground and in the Air – Quiz
- Zebras – Strong, Resilient, and Social Animals – Lesson
- Zebras – Strong, Resilient, and Social Animals – Quiz
- Alpacas – Mountain Dwellers With a Social Nature – Lesson
- Alpacas – Mountain Dwellers With a Social Nature – Quiz
- Beagles – Big-Hearted Scent Hounds – Lesson
- Beagles – Big-Hearted Scent Hounds – Quiz
- Cows – One of the Most Populous Animals on the Planet – Lesson
- Cows – One of the Most Populous Animals on the Planet – Quiz
- The Highly Intelligent Dolphin – Lesson
- The Highly Intelligent Dolphin – Quiz
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Space and Astronomy
- Mars: Just the Beginning? – Lesson
- Mars: Just the Beginning? – Quiz
- Six Billion ‘Earth-like’ Planets in the Milky Way Galaxy? – Lesson
- Six Billion ‘Earth-like’ Planets in the Milky Way Galaxy? – Quiz
- Did NASA Scientists Find Another Universe? – Lesson
- Did NASA Scientists Find Another Universe? – Quiz
- A New Planet Was Discovered – And Old Theories Must Change – Lesson
- A New Planet Was Discovered – And Old Theories Must Change – Quiz
- SpaceX Completes First Civilian Trip to Space – Lesson
- SpaceX Completes First Civilian Trip to Space – Quiz
- First Movie Filmed in Space Successful – Lesson
- First Movie Filmed in Space Successful – Quiz
- James Webb Telescope Heads to Deep Space – Lesson
- James Webb Telescope Heads to Deep Space – Quiz
- A Lot Is Happening on and Around the Moon – Lesson
- A Lot Is Happening on and Around the Moon – Quiz
- First-Ever Picture Taken of the Milky Way’s Black Hole – Lesson
- First-Ever Picture Taken of the Milky Way’s Black Hole – Quiz
- First James Webb Telescope Images Revealed – Lesson
- First James Webb Telescope Images Revealed – Quiz
- Buzz Aldrin Sells Jacket from the Moon Landing – Lesson
- Buzz Aldrin Sells Jacket from the Moon Landing – Quiz
- Humans at Home on the Moon – Could It Really Happen in This Decade? – Lesson
- Humans at Home on the Moon – Could It Really Happen in This Decade? – Quiz
- Winter on Mars – Lesson
- Winter on Mars – Quiz
- Pictures of Mars Show Hidden Figures – Lesson
- Pictures of Mars Show Hidden Figures – Quiz
- Jupiter and Venus Appear to ‘Kiss’ – Lesson
- Jupiter and Venus Appear to ‘Kiss’ – Quiz
- The James Webb Telescope Finds Six Ancient Galaxies – Lesson
- The James Webb Telescope Finds Six Ancient Galaxies – Quiz
- Would an EpiPen Work in Space? – Lesson
- Would an EpiPen Work in Space? – Quiz
- Satellite Spots Earth’s Second Moon? – Lesson
- Satellite Spots Earth’s Second Moon? – Quiz
- Space Mining – The Race is On and China is Leading – Lesson
- Space Mining – The Race is On and China is Leading – Quiz
- How Did Gold and Platinum Arrive on Earth – Lesson
- How Did Gold and Platinum Arrive on Earth – Quiz
- Odysseus Has Found Its New Home – Lesson
- Odysseus Has Found Its New Home – Quiz
- Earth – There’s No Place Like Home – Lesson
- Earth – There’s No Place Like Home – Quiz
- Mars – The Red Planet – Lesson
- Mars – The Red Planet – Quiz
- Of Eras and Ages: Life Begins in the Archean Eon – Lesson
- Of Eras and Ages: Life Begins in the Archean Eon – Quiz
- Venus – A Year in a Day – Lesson
- Venus – A Year in a Day- Quiz
- Mercury – The Speeding Messenger – Lesson
- Mercury – The Speeding Messenger – Quiz
- Of Eras and Ages: Ice, Oxygen, and Animals in the Proterozoic Eon – Lesson
- Of Eras and Ages: Ice, Oxygen, and Animals in the Proterozoic Eon – Quiz
- Jupiter – The Stormy Giant – Lesson
- Jupiter – The Stormy Giant – Quiz
- Saturn – The Great Timekeeper – Lesson
- Saturn – The Great Timekeeper – Quiz
- Of Eras and Ages: Life as We Know It in the Phanerozoic Eon – Lesson
- Of Eras and Ages: Life as We Know It in the Phanerozoic Eon – Quiz
- Uranus – The Sideways Planet – Lesson
- Uranus – The Sideways Planet – Quiz
- Neptune – Ice, Wind, and Mystery – Lesson
- Neptune – Ice, Wind, and Mystery – Quiz
- Pluto – The Forgotten Planet? – Lesson
- Pluto – The Forgotten Planet? – Quiz
- Astrology and Astronomy – From Omens to Orbits – Lesson
- Astrology and Astronomy – From Omens to Orbits – Quiz
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The Environment
- Red Tide: No Fun in the Florida Sun – Lesson
- Red Tide: No Fun in the Florida Sun – Quiz
- Leaded Gas Eradicated from the World, Says United Nations – Lesson
- Leaded Gas Eradicated from the World, Says United Nations – Quiz
- COVID Plastic Waste: A Big Problem for Oceans – Lesson
- COVID Plastic Waste: A Big Problem for Oceans – Quiz
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Archaeology and Paleontology
- Ancient Human Species Discovered – Lesson
- Ancient Human Species Discovered – Quiz
- Biblical City of Sodom Found in the Jordan Valley? – Lesson
- Biblical City of Sodom Found in the Jordan Valley? – Quiz
- Antarctic Explorer’s Ship Found After a Century – Lesson
- Antarctic Explorer’s Ship Found After a Century – Quiz
- Newly Found Diary Shows How Ancient Egyptians Built the Pyramids – Lesson
- Newly Found Diary Shows How Ancient Egyptians Built the Pyramids – Quiz
- Study Shows ‘Apocalyptic Dust’ Might Have Killed the Dinosaurs – Lesson
- Study Shows ‘Apocalyptic Dust’ Might Have Killed the Dinosaurs – Quiz
- Ancient Celestial Calendar Found in a 2,000-Year-Old Tomb – Lesson
- Ancient Celestial Calendar Found in a 2,000-Year-Old Tomb – Quiz
- Hiker Stumbles Upon Ancient Fossils While Hiking in Italy – Lesson
- Hiker Stumbles Upon Ancient Fossils While Hiking in Italy – Quiz
- Of Eras and Ages: Understanding Earth’s Geologic Time Scale – Lesson
- Of Eras and Ages: Understanding Earth’s Geologic Time Scale – Quiz
- Of Eras and Ages: Earth’s Chaotic Beginning in the Hadean Eon – Lesson
- Of Eras and Ages: Earth’s Chaotic Beginning in the Hadean Eon – Quiz
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Technology
- 3 Reasons to Protect Your Online Privacy – Lesson – VIDEO
- The Rise of Deepfakes – Lesson
- The Rise of Deepfakes – Quiz
- A New Mayflower Voyage, Captained by AI Technology – Lesson
- A New Mayflower Voyage, Captained by AI Technology – Quiz
- The Latest Supercomputer Is Breaking Speed Barriers – Lesson
- The Latest Supercomputer Is Breaking Speed Barriers – Quiz
- LNGenZ Survey: What is the Greatest American Invention? – Lesson
- LNGenZ Survey: What is the Greatest American Invention? – Quiz
- School and ChatGPT – Is it Cheating? – Lesson
- School and ChatGPT – Is it Cheating? – Quiz
- Artificial Intelligence Gets an Upgrade? – Lesson
- Artificial Intelligence Gets an Upgrade? – Quiz
- Scientists Plan to Bring the Dodo Bird Back from Extinction – Lesson
- Scientists Plan to Bring the Dodo Bird Back from Extinction – Quiz
- Is There Too Much Technology in Education? – Lesson
- Is There Too Much Technology in Education? – Quiz
- AI Coming to a Keyboard Near You – Lesson
- AI Coming to a Keyboard Near You – Quiz
- Is the NSA Browsing Your Browser History? – Lesson
- Is the NSA Browsing Your Browser History? – Quiz
- AI Can’t Compete With People Skills – Lesson
- AI Can’t Compete With People Skills – Quiz
- How Social Media Is Hazardous to Generation Z – and Beyond – Lesson
- How Social Media Is Hazardous to Generation Z – and Beyond – Quiz
- Surgeon General’s Warning for Social Media – Lesson
- Surgeon General’s Warning for Social Media – Quiz
- Pay With Your Face: Is the End of Cash Nigh? – Lesson
- Pay With Your Face: Is the End of Cash Nigh? – Quiz
- Can Artificial Intelligence Really End Cancer? – Lesson
- Can Artificial Intelligence Really End Cancer? – Quiz
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Mind and Body
- Teen Scientist’s Invention Mixes Music with Mental Health – Lesson
- Teen Scientist’s Invention Mixes Music with Mental Health – Quiz
- Man Receives First Pig Heart Transplant – Lesson
- Man Receives First Pig Heart Transplant – Quiz
- Sniffing Out the Truth About Smells – Lesson
- Sniffing Out the Truth About Smells – Quiz
- The Power of Playtime – Lesson
- The Power of Playtime – Quiz
- Is Language Getting More Emotional? – Lesson
- Is Language Getting More Emotional? – Quiz
- Scientists Say Household Chores Help Kids’ Brains – Lesson
- Scientists Say Household Chores Help Kids’ Brains – Quiz
- Transplant of Pig Kidney Into a Human Successful So Far – Lesson
- Transplant of Pig Kidney Into a Human Successful So Far – Quiz
- The Lack of a College Degree Is Shortening Lifespans – Lesson
- The Lack of a College Degree Is Shortening Lifespans – Quiz
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Flora and Fauna
- Dogs Can Tell When Humans Make a Mistake, Says Study – Lesson
- Dogs Can Tell When Humans Make a Mistake, Says Study – Quiz
- Jonathan: The World’s Oldest Living Tortoise – Lesson
- Jonathan: The World’s Oldest Living Tortoise – Quiz
- The Monarch Butterfly Makes a Surprise Return – Lesson
- The Monarch Butterfly Makes a Surprise Return – Quiz
- Bat Falcon Spotted in the United States for the First Time – Lesson
- Bat Falcon Spotted in United States for the First Time – Quiz
- Charles Darwin’s Notebooks Mysteriously Returned after 20 Years – Lesson
- Charles Darwin’s Notebooks Mysteriously Returned after 20 Years – Quiz
- Six Endangered Red Wolf Pups Born in Wildlife Refuge – Lesson
- Six Endangered Red Wolf Pups Born in Wildlife Refuge – Quiz
- Scientists Record Never-Before-Heard Whale Call – Lesson
- Scientists Record Never-Before Heard Whale Call – Quiz
- Underwater Meadow Gets Credit as the World’s Largest Living Plant – Lesson
- Underwater Meadow Gets Credit as the World’s Largest Living Plant – Quiz
- Scientists Trying to Bring the Tasmanian Tiger Back from Extinction – Lesson
- Scientists Trying to Bring the Tasmanian Tiger Back from Extinction – Quiz
- Jurassic Era Insect Found at Arizona Walmart – Lesson
- Jurassic Era Insect Found at Arizona Walmart – Quiz
- The Comeback of the Nearly Extinct Earless Lizard – Lesson
- The Comeback of the Nearly Extinct Earless Lizard – Quiz
- A Strange Golden Orb Found on the Ocean Floor Is Alive! – Lesson
- A Strange Golden Orb Found on the Ocean Floor Is Alive! – Quiz
- Peanut: The Pet Chicken With a World Record – Lesson
- Peanut: The Pet Chicken With a World Record – Quiz
- The Peculiar Venus Flytrap – Lesson
- The Peculiar Venus Flytrap – Quiz
- The Evolution of Plants – Lesson
- The Evolution of Plants – Quiz
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Mathematics
- Metric vs. Imperial: A Weighty Debate in Britain – Lesson
- Metric vs. Imperial: A Weighty Debate in Britain – Quiz
- The Abacus is Helping Kids Master Math Skills – Lesson
- The Abacus is Helping Kids Master Math Skills – Quiz
- Retired Engineer Discovers ‘Einstein’ Shape – Lesson
- Retired Engineer Discovers ‘Einstein’ Shape – Quiz
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Chemistry
Deer – One of the Most Successful Animal Breeds in the World – Lesson
There are around 40 different species of deer.
Deer and other members of the Cervidae family can be found on every continent in the world except for Antarctica. They are considered one of the most successful animal breeds due to their high rate of survivability and their ability to evolve. The mammal’s size, color, diet, and habits are dependent on the location, weather, and terrain where they reside. There are several different species of deer, including moose, caribou, white-tailed deer, elk, reindeer (like those that pull Santa’s sleigh), and more.
The Evolution of Deer
Deer are hooved animals (also called ruminant ungulates) that make up the large Cervidae family. Ancient fossils reveal that some species existed more than 20 million years ago. Scientists believe that deer back then were small and developed over time into the animals we see today. Scientists believe there are somewhere between 40 and 50 different species and three deer types, known as Capreolinnae, Cervinae, and Hydropotinae.
Preferred Diet and Habitat of the Deer
Deer are herbivores, meaning they eat only plants, fruits, seeds, and vegetables. They are also ruminants, which means they have four-chambered stomachs that can break down and ferment plants.
Deer habitats are dependent on the conditions in which they live. They live in forests, mountainous areas, and tundras. They are most active in the early morning, though they can be spotted foraging and moving throughout all the hours of the day.
Appearance and Behavior
Most species of deer have two hooves on each of their four feet, four-chambered stomachs, long skinny legs, short tails, and a fur coat that is commonly brown, red, or gray. The males of the species grow a set of beautiful antlers that are used for animal-on-animal combat and reproduction. The bone-like protrusions make it easy to differentiate a male deer from a female, except for caribou or reindeer, as females of those species grow antlers as well.
The smallest species of deer is the pudu from South America, which stands between 13 and 17 inches tall and weighs up to 26 pounds. At the other end of the spectrum is the moose. Moose can be as long as 10 feet and weigh up to 1,800 pounds. In the middle is the most common, the white-tailed deer.
As far as behavior goes, deer are social animals that live in groups called herds. In areas with plentiful foods, a herd of deer can be quite massive. The less food available, the smaller the herd. A herd provides protection against potential predators and allows for reproduction within the group
The Long List of Deer Predators
While deer can run at speeds of up to 43 miles per hour, they still can become dinner for many predatory creatures. Their fight-or-flight instinct is typically flight, as they tend to run away from any potential threat. The mammals can also leap long distances of up to 30 feet.
Not only do deer feed meat-eating animals such as tigers, mountain lions, bears, wolves, coyotes, jaguars, and humans but also their carcasses feed birds and small mammals. For centuries, deer have been a source of food, clothing, tools, and material for humans, and that continues to this day.
Santa’s Magically Famous Reindeer
From Rudolph to Dasher and the rest of the crew, reindeer (aka caribou) are especially popular during Christmastime. They live in colder climates in Northern Europe, Siberia, and North America
In some places, a group of magical reindeer are believed to guide Santa’s sleigh through the sky, making it possible for the jolly old man to deliver gifts to all the children of the world on Christmas Eve. Santa has nine special reindeer for the special task, and, without them, many children would be disappointed on Christmas morning.
Now Dasher, now Dancer, now Prancer and Vixen, on Comet, on Cupid, on Donner and Blitzen. The most famous of Santa’s team is Rudolph, the red-nosed reindeer, whose glowing proboscis lights the way for Santa’s sleigh.

- Deer are part of the large family Cervidae.
- The Cervidae family consists of hooved animals with four stomachs.
- Reindeer, the beautiful animals that pull Santa’s sleigh, are also members of the deer family.