INVERTEBRATES

The Most Plentiful Animal on Earth!

Home > Animals > Invertebrates

Invertebrates
Amphibians       Birds      Fish       Invertebrates       Mammals       Reptiles

As the name suggests, invertebrates are animals that do not possess a vertebral column (spine or backbone). With just one feature to define them all, this makes for a huge group of animals: insects, snails, worms, crabs, octopuses and many, many more. Invertebrates make up 97% of all living animals on the earth, and to say this is a wildly diverse grouping is an understatement. Consider the adult female Dolania americana (mayfly) who lives for only five minutes as an adult… or the Turritopsis dohrnii (jellyfish), who can – at least theoretically – live for 500+ billion years!


Featured Invertebrates

Clams
(Bivalvia)

“Clam” is an informal name that refers to bivalves (such as oysters, scallops, mussels, cockles, clams, and numerous…
Learn more >>

Comb jelly
(Ctenophorae)

This phylum of animals inhabits marine waters worldwide. They are named for their distinctive rows of cilia, or combs,…
Learn more >>

Corals
(Anthozoa)

These marine invertebrates are known for the dazzling calcified colonies they create as they multiply and grow. Each colony…
Learn more >>

Crinoids
(Crinoidea)

Crinoids, aptly nicknamed “feather stars”, can inhabit a wide range of marine environments and, judging by the fossil…
Learn more >>

Crustaceans
(Crustacea)

This very large group of arthropods includes familiar animals such as shrimp, crabs, lobsters, crayfish, and barnacles.…
Learn more >>

Earthworms
(Lumbricina)

These tube shaped, segmented worms commonly live in the soil and feed on both live and dead organic matter. Earthworms…
Learn more >>

Flatworms
(Platyhelminthes)

The structure of flatworms (flat) reflects their physiology – they have no body cavity other than a gut in most cases…
Learn more >>

Hydras
(Hydra)

Hydras make up a genus of tiny (up to 10 mm long), tentacle, aquatic, predatory animals that are commonly found in unpolluted…
Learn more >>

Insects
(Insecta)

This class of invertebrates has a chitinous skeleton, a three part body (consisting of a head, thorax, and abdomen), six…
Learn more >>

Jellyfish
(Cnidaria)

Jellyfish are typically free-swimming animals consisting of a gelatinous, inverted-umbrella body form (the bell) with…
Learn more >>

Leeches
(Clitellata)

While similar in some ways to earthworms, leeches differ in other distinct ways – for example, leeches do not have bristles…
Learn more >>

Mantis Shrimp
(Stomatopoda)

The mantis shrimp is not actually a shrimp, but a different kind of crustacean of the order Stomatopoda, known for its…
Learn more >>

Mosquito
(Culicidae)

Mosquitos are a family of small flies (the name “Mosquito” literally means “Small Fly” in Spanish)…
Learn more >>

Ragworms
(Nereidae)

This family of polychaete worms contains about 500 mostly marine species. They can be found in all water depths – hiding…
Learn more >>

Rotifers
(Rotifera)

These microscopic and near-microscopic pseudocoelomates are common in freshwater environments all over the world (and…
Learn more >>

Roundworms
(Nematode)

This diverse phylum is made up of an estimated 1 million species of roundworms, many of which are parasitic. Nematodes…
Learn more >>

Sea anemones
(Actiniaria)

These water dwelling, carnivorous animals are named for a type of flower, no doubt owing to their often colorful flower-like…
Learn more >>

Sea cucumbers
(Actinopyga echinites)

These tubular echinoderms can be found in oceans all over the world – in some deep sea environments they can be found…
Learn more >>

Sea stars
(Asteroidea)

Also known as starfish, these echinoderms are found on the sea floors of all the world’s oceans from the equatorial…
Learn more >>

Sea urchins
(Echinoidea)

These small, spiny, globular animals inhabit all the oceans of the world and can survive in shallow intertidal zones,…
Learn more >>

Snails and slugs
(Gastropoda)

“Snail” is a common name applied to most members of the class “Gastropoda” that have a coiled shell that is big…
Learn more >>

Spiders and other arachnids
(Arachnida)

The Arachnid class is comprised of over 100,000 described species and includes such familiar organisms as spiders, scorpions,…
Learn more >>

Sponges
(Porifera)

Sponges are aquatic, multicellular organisms whose body structure is full of holes and channels that allow water to circulate…
Learn more >>

Squids, octopi, nautili & cuttlefish
(Cephalopod)

These ocean dwelling animals are characterized by bilateral body symmetry, a prominent head, and a set of arms, or tentacles.…
Learn more >>

Tardigrades
(Tardigrada)

“Water bears” or “moss piglets” are tiny (~0.5 mm), aquatic, segmented animals that are able to withstand extreme…
Learn more >>

Tick
(Parasitiformes)

Ticks are small, blood-sucking arachnids of the order Parasitiformes, with over 900 known species.


Learn more >>




Interesting Facts

Learning about animals, you can discover many fascinating, even beautiful facts… but there are also things that can give you nightmares! Enter the strepsiptera (“twisted-wing parasite”). The adult female has no limbs, wings, or mouth – she simply lives in and feeds off her host (typically a wasp). When it becomes time to mate, she protrudes part of her abdomen from between the plates of her host and uses mind control to get the wasp to fly off to nearby males. The males have wings, and fly around for about five hours before dying, their only purpose seeking out females to mate with. After the female is impregnated, her own young grow and consume her. Once there is nothing left to eat, they leave their host wasp, infiltrate the wasp nest's nursery, then latch on to larvae to create their own “zombie wasp” host and continue the grisly cycle!

 


Interesting Articles

 


Gallery Photos

Invertebrates Species Gallery


Popular Videos

 

 

 


NAIA - National Animal Interest Alliance Discover Animals is a web-based educational resource offered by the NAIA
To learn more about the NAIA or about other NAIA programs, visit us at www.NAIAOnline.org
if you would like to help, join or support the NAIA or any of its programs please click here >>