A big part of my naturalist background is animal tracking, which means I’ve spent thousands of hours studying the behavior & biology of local mammals.
One of the most helpful things I ever learned along my journey was how to categorize mammals into their respective families.
Mammal families link together groups of animals that share similar characteristics and evolutionary history, making them easier to study and compare. Some of the most well known mammal families include the cat family, dog family & squirrel family.
This means that rather than studying each mammal in your bioregion individually, you can take a more top-down approach and learn entire families of animals together.
This will really speed up your learning curve because it dramatically reduces the sheer quantity of animals you have to learn.
Essentially – knowing the families makes you a lot more intuitive about what you’re actually seeing and what kinds of behaviors to look for.
The advantages of doing it this way are instantly applicable to field skills like animal tracking or simply watching wildlife for personal enjoyment.
A Few Rapid-Fire Facts About Mammal Families:
I’m constantly amazed when people sometimes think animals like foxes or weasels are in the cat family. These are relatively simple mistakes to correct.
Here’s what you need to know about mammal families for starters:
- There are currently more than 5000 known species of mammals in the world, but only 153 mammal families.
- The numbers are constantly changing depending on new discoveries in the animal kingdom and how scientists choose to lump & sort different species into taxonomical categories.
- Some mammal families are extremely widespread, existing almost everywhere in the world, while others are completely isolated to specific bio-regions.
- A lot of mammal families are just different categories of bats, which you won’t need to learn unless you live in a place with a huge diversity of bats. Same thing with many other types of animals.
- Therefore, you don’t always need 100% scientific accuracy to benefit from knowing a few local mammal families.
- For the average naturalist, a simplified taxonomy is much more practical.
For the average person who just wants to connect more easily with nature, there’s really only a handful of mammal families that everyone should start with.
If you’re just starting out – I highly recommend focusing on the most common and universally abundant families because that’s what you’re going to encounter most often.
For this article – I honed the list down to 8 families that will give you the greatest results for the least amount of time & effort.
#1 – The Dog Family (Canines)
The dog family exists almost everywhere around the world in both domestic & wild forms.
This family includes wolves, foxes, and even your lovable family pet.
A lot of people think canines are carnivores (eating exclusively meat), but they’re actually omnivores.
The omnivore diet can be easily observed by looking at the teeth, with sharp “canines” at the front, and a complete set of molars at the back (just like humans).
Dog family tracks have 4 toes, sharp claws, and their preferred style of movement is a trot.
They tend to be very social, often living in large family groups that engage in cooperative hunting and parenting.
Their dominant senses are primarily focused on hearing & scent, as evidenced by their large pointy ears and noses.
#2 – The Cat Family (Felines)
The cat family is another extremely common group of mammals that everyone is probably already familiar with in wild and domestic forms.
In comparison to the dog family – cats are actually much more carnivorous, with their daily diet being almost 100% meat.
This is why if you ever get the chance to examine cat teeth, you’ll notice all their teeth are extremely sharp and pointed, even the molars.
Similar to dog tracks, cats have 4 toes, but their claws are retractable so they often do not show in the prints. This a fairly common way to tell the difference between cat & dog tracks.
Cats also tend to move much slower than the dog family. Their preferred movement style is a walk that enables them to be much more stealthy.
They tend to be much more solitary, with hunting & child-rearing being done solo.
If you compare cat & dog faces you’ll notice cat ears & noses are proportionately smaller, but their eyes are bigger.
In this respect, cats are actually closer to humans and rely heavily on their sense of sight.
#3 – The Weasel Family (Mustelidae)
The weasel family contains some of the most common and abundant predators around the world, but because most of them are so small & slinky – many people have very little experience with this family.
The weasel family (or mustelids) includes everything from tiny, almost mouse-sized weasels, to much larger creatures like badgers & wolverines.
Weasels are incredibly vicious and efficient predators. They’re capable of routinely taking down prey much larger than themselves.
They also tend to have a very high metabolism so they need to hunt and eat often.
Their teeth are very sharp just like cat teeth, but perhaps their most striking physical feature is the long slinkiness of their body which enables them to enter holes and burrows in pursuit of prey.
Weasel tracks have 5 toes with very sharp claws.
They tend to move in a slinky loping type movement pattern, and some species like otters are excellent swimmers.
#4 – Rabbits & Hares (Leporidae)
The rabbit family is an abundant group of non-predatory animals that live in many parts of the world.
Along with their cousins (the pika family), they form the Lagomorph order, which has worldwide distribution.
These animals are known for having very large ears and massive hind feet they use to hop around while eating fresh vegetation.
A big part of the rabbit defence strategy from predators depends on stealth first and also their ability to run very fast when being pursued.
Because rabbits are herbivores, their tooth structure is completely different from cats, dogs & weasels.
They have very prominent incisors (like human front teeth) used for snipping off vegetation.
A gross fact about rabbits is that they reduce the size of their digestive system by ingesting their faeces after it’s already gone through once.
#5 – The Squirrel Family (Sciuridae)
Squirrels are a hugely abundant and well distributed family of rodents that can be found all over the world.
Some varieties like ground squirrels live in massive colonies and burrow underground for safety, while others spend most of their time up in trees.
Rodents like squirrels are unique in the animal kingdom in that they have 4 toes on their front paws, and 5 toes on the hind.
Their large front incisors can be distinguished from the teeth of other herbivores by a bright orange color.
An interesting feature of the squirrel family is that many of them have an extremely well developed vocal alarm system with calls they use to warn each other of danger.
Other rodent families include various families of mice, porcupines, and even larger mammals like beavers.
#6 – The Deer Family (Cervidae)
In the world of large grazing mammals, the deer family is one of the most widespread and abundant groups.
This family includes a large range of sizes and habitat preferences from caribou living in open grasslands & tundra, to much smaller species living in dense jungles & forests.
Deer are ruminants, which means they digest their fibrous diets in stages by regurgitating & chewing cud. They feed in cycles, first filling their stomach, before retreating off to safe places for rest and digestion.
Like all herbivores, the deer family don’t have sharp teeth for chomping meat, and instead there’s just 4 large incisors at the front, and a complete set of molars at the back.
Deer tracks typically show 2 hoofed toes, except in deep substrate where their dew claws can sometimes be seen. These tracks are completely unlike any of the other mammal families we’ve discussed so far.
In the forest, members of the deer family can live alone or in small groups, but in more open territory it’s possible to find massive herds with hundreds or even thousands of animals living together. These can be some of the largest herds in the world.
The deer family tends to move in a walking pattern, but they are quite capable of jumping and quickly escaping when danger is nearby.
#7 – The Bear Family (Ursidae)
The bear family is omnivorous like canines. It includes some incredibly large animals like polar bears with adult males weighing in at 450 kg (992 lbs). While the smallest species can have adult males as small as 27 kg (60 lbs).
Bears have a reputation for being dangerous because their large size & powerful jaws/claws make them very capable defenders.
They can be quite large and powerful animals, but most bears are actually much more concerned with staying away from other animals than attacking them.
Most bears prefer to eat a mixed diet of fruit, berries, fish & anything else they can scavenge up in the forest, and only sometimes will actively hunt large prey.
Bear tracks have five toes with large claws used for climbing and scavenging for insects. Their hind tracks can sometimes look almost human, but the trail is unmistakably different.
Bears prefer to move in a slow, ambling walk. Many species are quite skilled climbers, and they can also stand on their hind feet to get a better view.
Even with their size, when provoked or scared, bears can run incredibly fast.
Their dominant sense is smell as evidenced by their small eyes, small ears, and big nose.
#8 – The Great Ape Family (Hominidae)
The ape family is the most widely distributed family of mammals on the planet.
Most species are found exclusively in parts of Africa & Asia, except for humans, who have managed to survive and dominate on every continent.
Probably the most striking feature of apes is their incredible intelligence.
They’re highly social and capable of communication skills far beyond what most other animals can demonstrate. They frequently use tools and pass on techniques for using those tools from generation to generation.
Members of the ape family are technically omnivores, as evidenced by their tooth structure, which is very similar to dogs and bears.
Yet many wild apes still tend to eat a mostly vegetarian diet, only occasionally dipping into meat-eating.
There are however, cases where wild apes have been observed engaging in highly intelligent and organized hunting behaviors. It’s fascinating to observe animals that are so closely related to humans, and wonder about our common ancestral history.
An amazing thing to realize is that 96% of our human DNA is identical to chimp DNA.
Most domesticated apes (humans) tend to eat a lot of meat, but many become vegetarians for a variety of reasons.
Some apes like Orang-utans are mostly arboreal (living in tree-tops), while others spend most of their time on the ground.
Like all primates – we apes have opposable thumbs which enable us to grasp & hold objects. We have 5 toes on both our hands and feet.
A Final Point About Mammal Orders, Families & Species:
Sometimes you’ll find it’s actually more practical to categorize animals by their taxonomical order instead of their actual family.
This is useful in cases where there might only be a small number of species to begin with, or when the similarities between families are so subtle that the physical differences aren’t actually all that noticeable out in the real world.
For example: I personally tend to lump all the bats together in one group because there’s only one family of bats living in my area.
But if you live in a place that has lots of bats like South America or Australia, you might choose to split them up by family.
As you continue to study mammals, you might sometimes choose to focus on an entire taxonomical order, before chunking down to the family level.
Then as you become more advanced, you can graduate to focusing on individual species to gain an appreciation for the specific differences that exist between individual types of cats, canines, weasels, etc.