Mammals are classified into 26 living (extant) orders based on anatomical, genetic, and evolutionary traits. Here’s an alphabetical list of all 26 extant mammalian orders, each representing a unique group of mammals:

1. Afrosoricida – tenrecs and golden moles
2. Artiodactyla – even-toed ungulates (e.g., deer, pigs, giraffes, cows)
3. Carnivora – carnivores (e.g., dogs, cats, bears, seals)
4. Cetacea – whales, dolphins, porpoises
5. Chiroptera – bats
6. Cingulata – armadillos
7. Dermoptera – colugos (flying lemurs)
8. Didelphimorphia – opossums
9. Diprotodontia – kangaroos, koalas, wombats
10. Eulipotyphla – hedgehogs, shrews, moles
11. Hyracoidea – hyraxes
12. Lagomorpha – rabbits, hares, pikas
13. Macroscelidea – elephant shrews
14. Microbiotheria – monito del monte (South American marsupial)
15. Monotremata – egg-laying mammals (platypus, echidnas)
16. Notoryctemorphia – marsupial moles
17. Paucituberculata – shrew opossums
18. Peramelemorphia – bandicoots and bilbies
19. Perissodactyla – odd-toed ungulates (e.g., horses, rhinos, tapirs)
20. Pholidota – pangolins
21. Pilosa – sloths and anteaters
22. Primates – monkeys, apes, humans, lemurs
23. Proboscidea – elephants
24. Rodentia – rodents (e.g., mice, rats, squirrels, beavers)
25. Scandentia – treeshrews
26. Sirenia – manatees and dugongs

The animal people often say is “90% human” is the chimpanzee, and it’s not far off. Genetically, chimps share about 98.8% of our DNA, making them our closest living relatives.

That number gets thrown around a lot, sometimes simplified as “90% human,” but what really makes chimps feel familiar isn’t just their genes. It’s the way they act. They use tools, show emotions like joy or grief, form friendships, solve problems, and even throw tantrums. Watching a chimp can feel a lot like watching a mirror with a little bit of jungle thrown in.

So while they’re not actually 90% human, they’re close enough to remind us just how connected we are to the rest of the animal kingdom.

Yep, dolphins are definitely mammals—even though they live in the ocean and kind of look like fish, they’re much more like us than you might think.

They breathe air through lungs (not gills), they’re warm-blooded, they give birth to live babies, and they even nurse their young with milk, just like other mammals. Baby dolphins will stay close to their moms and drink milk until they’re old enough to hunt on their own.

They even have a little bit of hair when they’re born—usually around the snout, but it falls out pretty quickly.

So while they might swim like fish, dolphins check every box on the mammal list. Smart, social, and full of personality—they’re basically the ocean’s version of us.

Nope, a monkey is not a rodent.

Monkeys are primates, which is the same group humans, apes, and lemurs belong to. Rodents, on the other hand, include animals like mice, rats, squirrels, and beavers.

Here’s the difference in simple terms:

Primates (like monkeys) have bigger brains, more complex behavior, and often use their hands to grasp and interact with their environment.

Rodents have large front teeth that never stop growing and are built more for gnawing.

So while a monkey might look small and quick like some rodents, it’s actually way more closely related to humans than to mice.

Absolutely, a horse is totally a mammal.

They’re warm-blooded, have hair (even if it’s just that short coat), give birth to live foals, and feed their babies with milk—just like all mammals do. Plus, they breathe air with lungs, not gills or anything else.

So next time you see a horse running around or hanging out in a field, just remember it’s one of the many amazing mammals out there.

No, a shark is not a mammal—it’s a fish.

Sharks breathe through gills, lay eggs or have live young without nursing them, and they’re cold-blooded. Unlike mammals, they don’t have hair or produce milk.

So even though sharks are powerful swimmers and top predators in the ocean, they’re part of the fish family, not the mammal club.

When people talk about an animal being 15,000 years old, they usually mean the age of a living individual animal or a species that has been around for that long.

No single animal lives 15,000 years, but here are some ways the number comes up:

Greenland sharks are some of the longest-living vertebrates on Earth. Scientists estimate they can live up to 400 years or more—which is incredibly old but still far from 15,000 years.

Clonal organisms like certain types of sea grass, corals, or fungi can be thousands of years old because they reproduce by cloning themselves, essentially creating genetically identical copies that live on for millennia.

Some ancient trees, like the bristlecone pine, are over 5,000 years old.

If you meant a specific animal or a fossil discovery that’s 15,000 years old, let me know! But no known individual animal lives that long.

Yes, humans do share some DNA with bananas—but it’s not as weird as it sounds!

About 50% of our genes have counterparts in bananas. That’s because many basic cellular processes—like how cells produce energy, copy DNA, or make proteins—are similar across all living things. These fundamental functions rely on genes that have been conserved through billions of years of evolution.

So while we definitely don’t look like bananas or share traits with them, at the microscopic level, there’s a surprising amount of overlap in the building blocks of life.

It’s a cool reminder that all life on Earth is connected in some way!

No, a crocodile is not a mammal. It’s a reptile.

Crocodiles lay eggs, are cold-blooded, have scaly skin, and breathe air with lungs. They don’t produce milk or have fur like mammals do.

So even though crocodiles can be pretty fierce and share some traits with mammals, they’re definitely part of the reptile family.

Orcas are called killer whales because of their reputation as powerful hunters. Long ago, sailors noticed orcas hunting large whales and other big sea animals, so they nicknamed them “whale killers.” Over time, that got flipped around to “killer whales.”

Even though orcas are actually dolphins—not true whales—they’re top predators in the ocean and hunt in groups, using smart strategies to catch everything from fish to seals to whales. The name stuck because people were impressed (and maybe a little scared) by how effective and fierce these animals are.

One mammal with around 100 individuals left in the wild is the Amur leopard.

The Amur leopard is one of the rarest big cats on Earth, living mainly in the Russian Far East and parts of northeast China. Thanks to conservation efforts, their numbers have slowly increased, but they still hover around 100 in the wild, making them critically endangered.

Another example (though fewer than 100 now) is the Northern white rhinoceros, with only two females left, so it’s basically extinct in the wild.

Mammals are warm-blooded animals that have hair or fur, breathe air through lungs, give birth to live young (mostly), and feed their babies with milk.

No, some mammals like whales, dolphins, seals, and otters live in water, while others live on land or even in the air (bats).

There are about 6,400 known species of mammals worldwide, ranging from tiny shrews to massive elephants.

Most mammals give birth to live young, but a few like the platypus and echidnas lay eggs. These are called monotremes.

Hair or fur helps mammals stay warm and protect their skin.