Are Sloths Mammals? Let’s Find Out…..

Sloths – the tree-dwelling, slow-moving creatures that so many people have fallen in love with (I am one of those people, by the way). Sloths are so many things – they are cute, they are lovable, they are adorable, they are wonderful…..I could go on and on for quite awhile here. But what kind of animal are they? Are sloths mammals? Or are they defined as something else within the animal kingdom?

In today’s article, I will elaborate on this by discussing some key topics and going into more detail within each of these topics. Specifically, I will be coming up with a definition of the word “mammal”, I will compare characteristics of sloths to characteristics of mammals, I will be discussing where sloths came from, I will discuss which animals sloths have as relatives, and I will provide an answer to our original question. So, let’s begin, shall we…..


What Is The Definition Of A Mammal?

There are many common characteristics that all mammals share, which helps to come up with a definition. Some of these characteristics are as follows:

  • Mammals are warm-blooded, which allows them to always maintain a very consistent temperature. This allows them to live in (and be able to survive in) so many different parts of the world. Mammals can be found living in hot areas, in cold areas, in oceans, in caves, etc.
  • Mammals use their lungs to breathe air.
  • Mammals have hair or fur. Whether it is long or short (or somewhere in between), if they have hair or fur, they are mammals.
  • Mammals have a heart that consists of four chambers.
  • If babies drink milk that comes from the body of their mother, they are mammals.
  • Mammals have backbones (which most animals actually don’t have). In more technical terms, animals that have backbones are called “vertebrates” and animals that don’t have backbones are called “invertebrates”.
  • Mammals do not continue growing (at least for the most part) once they become adults.
  • Mammals will only develop two sets of teeth throughout their life (if they have teeth, that is – some mammals, like anteaters, do not).
  • Almost all mammals have a total of seven bones in their necks.


Sloth Characteristics

So, are sloths mammals? When considering the aforementioned characteristics that all mammals share, let’s see if the characteristics of sloths are the same:

  • Sloths are warm-blooded and live in the rainforests of Central and South America.
  • Sloths use their lungs to breathe air. Despite the fact that sloths move slowly on land and in trees, they actually know how to swim quite well and are able to hold their breath for 40 minutes.
  • Sloths have fur (which various critters, including algae, live on).
  • Sloths have a heart that consists of four chambers. They also have a four-part stomach that takes a long time to digest what they eat.
  • Baby sloths drink milk that comes from their mothers.
  • Sloths have backbones.
  • Sloths do not continue growing (at least for the most part) once they become adults.
  • Sloths will only develop two sets of teeth throughout their life.

As far as the last common characteristic that all mammals share presented above goes (a total of seven bones in their necks), sloths deviate from this (two-toed sloths have five vertebrae in their neck and three-toed ones have nine).

So, to answer our question, “Are sloths mammals?” The answer is, “Yes, they most definitely are”. As a side note, there are 6,000+ mammals on this planet (humans are one of them) and of all of these mammals, sloths are the slowest-moving ones. For more information about this, check out my article titled “Why Do Sloths Move Slowly? It’s About Survival“.


Where Did Sloths Come From?

In one form of species or another, sloths have been around for millions of years (over 35 million years, actually). Over all of those years, they have evolved in numerous ways to become the slowest-moving mammal (and one of the slowest-moving animals) on the planet. So, how did this happen? Let’s take a trip back in time to learn more…..

Introducing Xenarthra. Xenarthra? What the heck is that? It sounds likes a superhero in a comic book or something like that. Well, not quite. 50+ million years ago, there was a group of animals that could be found in South America. While in a long period of isolation, these animals were able to develop and have been given the name “Xenarthra”, which translated means “strange joints”. The strangeness of these joints is shared by all Xenarthrans as their backbones have extra joints. Generally, Xenarthrans have also adapted to being “diggers”.


The Family Tree Of A Sloth

As part of the Xenarthra, the closest relative to the sloth is the anteater. The second closest relative is the armadillo. Within the “sloth family”, there are two categories: two-toed and three-toed. While two-toed and three-toed sloths have many similarities, they also have many differences amongst themselves, too. For more details about this, see my article titled “Different Types Of Sloths – How Many Are There?

Two-toed and three-toed sloths have undergone evolutionary journeys independent of each other. As a result of this, these two categories of sloths are actually distant relatives. From a biological/scientific perspective, we have something that looks like this:

  • Xenarthra
    • Armadillos
    • Pilosa
      • Anteaters
      • Folivora
        • Two-toed sloths
        • Three-toed sloths


The Answer To Our Question

Throughout this article, I presented information in an attempt to answer the question, “Are sloths mammals?”. In doing so, I came up with a definition of the word “mammal”, I compared characteristics of sloths to characteristics of mammals, I discussed where sloths came from, and I discussed which animals sloths have as relatives. Based on this information, it can be seen that sloths most definitely are mammals.

In addition to being mammals, sloths are also cute, gentle, lovable, adorable, and wonderful creatures. Wouldn’t it be nice if we, as humans, were able to slow down a little bit and enjoy life a little bit more? To be a little bit more like the sloth? Thank you for taking the time to read this article. If you have any comments or questions, please feel free to leave them in the section below and I will be sure to get back to you.

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  • Super interesting information about whether sloths are mammals. After reading your post I got to know that they are mammals. Through your website I got to know about sloths and I find them super cute and adorable.

    Thank you for sharing this amazing information with us.

    Best regards.

    • I am happy to hear that you are learning something from my website. I am also happy to hear that you find sloths super cute and adorable (as I also do). Thanks for commenting and best regards to you, too.

  • I must confess that I’ve never heard of sloths. You are right that it would be a good idea to slow down in life a little bit and enjoy the sloth and finding out how cute and lovely they are.
    Thank you for the great article – it’s very informative.

  • Great article. I have heard of the sloths and seen them on TV from time to time but never the history like you explained.

    Thanks for sharing!

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