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Animal Randomizer

For teaching the labels

The six animal groups, in plain words

These six are classroom categories, not six scientific classes. They are useful, and each one has animals in this very catalog that break its rule. Knowing which ones is what turns a sorting exercise into a good lesson.

Start with the backbone

One question does most of the work. Does the animal have a backbone?

If it does not, it is an invertebrate, and that is most animals on Earth. If it does, it belongs to one of the five categories below, and the rest of this guide is about telling those five apart.

Each category below gives what is usually true, then the animals in this catalog that break it. The exceptions are the interesting part. A child who meets a pangolin with an untroubled rule about scales learns the wrong lesson.

Mammals

90 here

Usually: hair or fur, and young that drink milk. The milk is the dependable part.

In the catalog: African elephant, gray wolf, capybara, orca

What breaks the rule here

A platypus and a short-beaked echidna lay eggs. A pangolin and a nine-banded armadillo are covered in scales and plates, with no fur you can see. A blue whale, an orca and a West Indian manatee live in the sea. All of them feed their young on milk, which is why all of them are mammals.

Birds

89 here

Usually: feathers. Every bird has them, and nothing else in this catalog does.

In the catalog: barn owl, emperor penguin, kiwi, ruby-throated hummingbird

The rule holds. Flight is the trap

This is the one category where the simple rule works. Flight is not the rule: an ostrich, an emperor penguin, a kiwi, an emu, a southern cassowary and a greater rhea cannot fly. A common vampire bat flies well and is a mammal.

Reptiles

62 here

Usually: scales, air breathing, and eggs laid on land. Lizards, snakes, turtles and crocodiles all sit here.

In the catalog: Komodo dragon, king cobra, green sea turtle, American alligator

What breaks the rule here

A boa constrictor, a green anaconda and an adder give birth to live young. And scales alone settle nothing: a pangolin is covered in them and is a mammal.

Amphibians

46 here

Usually: bare skin with no scales, young that live in water, adults that come out onto land.

In the catalog: common frog, fire salamander, axolotl, great crested newt

What breaks the rule here

An axolotl, an olm, a hellbender, a siren, an amphiuma and a mudpuppy never make the move to land. They stay in the water for life. Note also that skin is something to look at in a photograph, not something to test by touching an animal you do not know.

Fish

72 here

Usually: gills, fins, and a whole life spent in water.

In the catalog: great white shark, clownfish, lined seahorse, moray eel

What breaks the rule here

A mudskipper walks about on mud and spends hours out of the water. A lungfish breathes air. A flying fish leaves the water altogether. The names mislead too: a whale shark is a fish and a blue whale is a mammal, while jellyfish, cuttlefish, crayfish and starfish are not fish at all.

Invertebrates

90 here

No backbone. That is the whole of it.

In the catalog: giant Pacific octopus, honey bee, garden snail, sea urchin

Not really one kind of animal

An octopus and a honey bee have almost nothing in common. They share a label because of something they both lack. Most animals on Earth are in here, and the other five categories are the exceptions.

A sorting guide, not a test

Work down the list and stop at the first yes. It will place most animals, and it is a guide rather than a test, because some animals genuinely do not fit.

  1. No backbone? It is an invertebrate.
  2. Feathers? It is a bird.
  3. Drinks milk as a baby? It is a mammal.
  4. Bare skin, and young that live in water? It is an amphibian.
  5. Scales, and it breathes air on land? It is a reptile.
  6. Gills and fins for the whole of life? It is a fish.

Milk comes before scales on purpose. Ask about scales first and a pangolin ends up a reptile.

When an animal will not fit, that is the scheme running out, not the child getting it wrong. Show the group label the generator gives, and talk about why the rule missed it. A mudskipper is worth five minutes of anyone’s lesson.

Where these labels stop

Worth saying out loud to an older class, because a sharp child will find the seam without help.

  • Only some of these six are formal groups in biology. Mammals, birds and amphibians are. Fish and invertebrates are not: they are convenient bundles.
  • Fish are not one branch. A great white shark has a skeleton of cartilage and an Atlantic salmon has one of bone. They are further apart from each other than a salmon is from a cow.
  • Invertebrate is defined by an absence, which is why an octopus and a honey bee share a label.
  • Reptiles as taught in class leave out birds, although in modern biology birds sit inside the reptile branch. The classroom six are a ladder, and it is fine to say so while children are climbing it.

Using this with the generator

  1. Leave Group on All groups.
  2. Enter the number of children.
  3. Select Generate.
  4. Hide the coloured group labels from the children.
  5. Ask each child to sort their animal with the list above.
  6. Show the labels and compare.
  7. Collect the animals that did not fit and discuss them.

All 449 animals carry one of these six labels. The labels were checked as a whole against Integrated Taxonomic Information System (ITIS), not animal by animal. The methodology says exactly how far that checking goes.