An animal is an animal.  It seems like such an obvious thing, but in fact many people, especially kids, may not fully understand what an animal is.

On a recent hike with my kids I realized that it may not be clear to them what are animals and what are not animals.  They know that plants and trees are not animals, but it becomes a bit murkier if I start asking them about other things, such as bugs, worms, and even birds.  This post is my attempt to make it clear to parents and kids what an animal actually is.

Seven Main Kingdoms of Life

To begin with I want to remind everyone of the big picture.  All forms of life belong to one of the main kingdoms of life.  These kingdoms of life are a system that scientists developed to organize life.  According to scientists, there are six main kingdoms, one of which is animals.

The animal kingdom is divided into two main categories – those with backbones and those without backbones.

A Simple Definition of an Animal

You can look up the definition of an animal in a dictionary, or on the internet and find various definitions.  They may differ, but they share the same overall meaning:

Animal – a multicellular, living organism that feeds on organic matter, can move independently at some point in their life, and belong to the kingdom Animalia.

What Makes an Animal an Animal?

1. Animals are multicellular.  It may be made up of 1,031 cells or like a human have trillions of cells.
2. All animals are eukaryotes.  Basically, this means that the individual cells have a nuclei and can group together to form multicellular organisms.
3. Animals have specialized cells.  They develop cells that have a specific function such as senses or muscles.
4. Animals use sexual reproduction to make babies.  This gives them a competitive advantage over other species.
5. Animals have the ability to move.  At some stage in their life all animals have the ability to move.  This is a major difference between animals and fungus or plants.
6. Animals eat carbon based foods.  This means that all animals have the ability to eat things that their body can then get the energy its needs for life – growth, reproduction, etc…This is in contrast to plants which can create their own energy from the sun.

Are These Animals or Not?

Well, I hope that is clear.  Now, I want to give you a short test by showing you some photos and letting you guess if they are animals or not.  Answers at the bottom of post.

Fish – yes.

Bird – yes.

Mushroom – no.

Butterfly – yes.

Earthworm – yes.

How did you do?