Ants are not mammals. While both are animals, they are very much different from each other.
Mammals are a group of animals that have hair, produce milk for their young, and are warm-blooded. Ants don’t have any of those characteristics. Instead, as insects, they’re classified through their 3 body segments, 6 legs, and wings.
In this article we’ll learn more about why ants are not mammals as we discuss the following:
- Characteristics of mammals
- Differences between ants and mammals
What are Mammals? Characteristics of Mammals
Mammals refer to the members of class Mammalia. It’s a diverse group of around 5,000 to 5,500 species which includes animals such as rats, cats, dogs, apes, and humans.
Mammals are considered to be the most successful group of vertebrates. They’ve evolved specialized traits that help them survive in a variety of habitats. 
These traits are as follows:
Female mammals have milk-producing glands called mammary glands. These glands are large, modified sweat glands located on the breast.
Mammals use these mammary glands to nurse and nourish their young.
Fur or Hair
A rather obvious mammalian feature is the presence of fur or hair at least at some point in their life cycle. This hair serves multiple functions, from sensing, communication, camouflage, and thermoregulation.
Sweat glands are secretory glands mammals use to secrete sweat. This sweat is a clear liquid that mammals use to cool down and thermoregulate.
Middle Ear Bones
The mammalian middle ear consists of three tiny bones: the hammer, anvil, and stirrup. These three bones work together to amplify sound and send sound waves to the inner ear.
Why are Ants Not Mammals?
Ants aren’t mammals because they don’t have mammalian characteristics. To be specific, they don’t have the following:
Ants Don’t Have Sweat or Mammary Glands
Ants don’t have sweat or mammary glands. They don’t sweat to cool down and have no capability to produce milk for their young. Instead, they rely on the environment for both thermoregulation and food.
Ants Don’t Have Ears
Ants don’t have the same internal structure as mammals because they don’t have ears. They hear through vibrations on the ground that they feel through their feet.
See this article to learn more about how ants hear.
Ants Don’t Have Hair
Some ant species have hair-like structures that they use to prevent overheating. These hairs are called seta (pl. setae) and aren’t the same as mammalian hairs.
Unlike mammalian hair that’s composed of keratin, seta is composed of chitin.
Other Differences Between Ants and Mammals
Ants and mammals are further differentiated by the following characteristics:
- Ants are Invertebrates: Unlike mammals, ants don’t have spines or internal bone structures. Instead, they have exoskeletons(external skeletons) which provide structural support and shape.
- Ants are Cold-Blooded: Mammals are warm-blooded and produce body heat internally. Ants, however, are cold-blooded and have to rely on the environment for thermoregulation.
- Ants Don’t Have Lungs: Ants don’t breathe in oxygen in the same way that mammals do. Instead of lungs, they make use of tiny holes on the surface of their bodies called spiracles. These spiracles connect to tubes that distribute oxygen straight to the cells.
- Ants Lay Eggs: Ants are oviparous, meaning they lay eggs to produce young. Mammals on the other hand are usually viviparous or give birth to live offspring.
What Type of Animal are Ants?
Ants are insects. They have segmented bodies, three pairs of jointed legs, and two pairs of wings.
To learn more, see this article on why ants are insects.
Summary: Are Ants Mammals?
To summarize, ants are not mammals. They don’t share the defining characteristics that classify animals as mammals. They don’t have sweat glands, mammary glands, hair, and three middle ear bones.
Apart from that they also differ in a number of ways including the following:
- Skeletal structure
- Mode of reproduction
- Respiratory system