What is an Invertebrate?
An invertebrate is an animal that does NOT have a backbone. Invertebrates make up over
95% of ALL animal life. Invertebrates live in every habitat found on earth, from the deep ocean and
polar ice caps, to even the driest deserts. Every living creature on earth usually depends on several
invertebrate species to survive.
Invertebrates include animals such as:
• Jellyfish
• Corals
• Sea Sponges
• Worms
• Snails and slugs
• Octopus, Squid, Cuttlefish and Nautilus
• Sea Squirts
• Sea Cucumber
• Crabs, Crayfish and Lobsters
• Starfish
• Sea Urchins
• Centipedes and Millipedes
• Spiders and other arachnids
• Insects such as flies, ants, beetles, butterflies, termites,
earwigs and more.
Courtesy London Zoo
Invertebrates usually have a hard shell or similar on the outside of their bodies. We call this an
‘exoskeleton’. In some invertebrates like lobsters, the exoskeleton is quite hard like a suit of armour,
however some invertebrates don’t possess an exoskeleton at all. Animals such as worms and slugs
have adapted to living without an exoskeleton by living in habitats where they won’t dry out or be at
risk of attack. Some animals such as snails, have a shell in which they can retreat if the weather gets
too hot and dry or if a predator tries to attack them.
Other animals, such as fish, amphibians, reptiles, mammals and birds have a backbone and a
skeleton inside their bodies. We call these animals ‘vertebrates’.