Mollusks
KNOWN SPECIES
80,548
3.42% of our world's living things are mollusks
CHARACTERISTICS
- animals without a backbone (invertebrates)
- most have shells and a hard-toothed feeding structure called a radula
SIZE RANGE
0.04 inch to 59 feet (1 millimeter to 18 meters)
WHERE THEY LIVE
in oceans, fresh water, and in moist land areas
Here are just SOME of the world’s mollusks:
![Sticker about size](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_size_sticker/5943379-2-eng-US/mollusks_size_sticker_full_495.png 495w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_size_sticker/5943379-2-eng-US/mollusks_size_sticker_full_990.png 600w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_size_sticker/5943379-2-eng-US/mollusks_size_sticker_full_1468.png 600w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_size_sticker/5943379-2-eng-US/mollusks_size_sticker_full_1980.png 600w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_size_sticker/5943379-2-eng-US/mollusks_size_sticker_full_2475.png 600w)
cuttlefish
SCIENTIFIC NAME:
Sepia pharaonis
![Squid with zebra stripes](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_cuttlefish/5941443-2-eng-US/mollusks_cuttlefish_full_495.png 495w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_cuttlefish/5941443-2-eng-US/mollusks_cuttlefish_full_990.png 990w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_cuttlefish/5941443-2-eng-US/mollusks_cuttlefish_full_1468.png 1468w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_cuttlefish/5941443-2-eng-US/mollusks_cuttlefish_full_1980.png 1980w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_cuttlefish/5941443-2-eng-US/mollusks_cuttlefish_full_2475.png 2000w)
tidewater mucket
SCIENTIFIC NAME:
Atlanticoncha ochracea
![Brown shelled bivalve](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_tidewater_mucket/5941467-1-eng-US/mollusks_tidewater_mucket_full_495.png 495w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_tidewater_mucket/5941467-1-eng-US/mollusks_tidewater_mucket_full_990.png 990w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_tidewater_mucket/5941467-1-eng-US/mollusks_tidewater_mucket_full_1468.png 1468w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_tidewater_mucket/5941467-1-eng-US/mollusks_tidewater_mucket_full_1980.png 1980w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_tidewater_mucket/5941467-1-eng-US/mollusks_tidewater_mucket_full_2475.png 2300w)
greater blue-ringed octopus
SCIENTIFIC NAME:
Hapalochlaena lunulata
![Octopus with blue rings swimming](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_blue_ringed_octopus/5941439-1-eng-US/mollusks_blue_ringed_octopus_full_495.png 495w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_blue_ringed_octopus/5941439-1-eng-US/mollusks_blue_ringed_octopus_full_990.png 990w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_blue_ringed_octopus/5941439-1-eng-US/mollusks_blue_ringed_octopus_full_1468.png 1468w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_blue_ringed_octopus/5941439-1-eng-US/mollusks_blue_ringed_octopus_full_1980.png 1800w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_blue_ringed_octopus/5941439-1-eng-US/mollusks_blue_ringed_octopus_full_2475.png 1800w)
chambered nautilus
SCIENTIFIC NAME:
Nautilus pompilius
![Brown and white striped shell](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_nautilus/5941447-1-eng-US/mollusks_nautilus_full_495.png 495w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_nautilus/5941447-1-eng-US/mollusks_nautilus_full_990.png 990w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_nautilus/5941447-1-eng-US/mollusks_nautilus_full_1468.png 1468w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_nautilus/5941447-1-eng-US/mollusks_nautilus_full_1980.png 1980w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_nautilus/5941447-1-eng-US/mollusks_nautilus_full_2475.png 2340w)
Spanish shawl nudibranch
SCIENTIFIC NAME:
Flabellinopsis iodinea
![Purple slug with yellow spikes](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_spanish_shawl_nudibranch/5941459-1-eng-US/mollusks_spanish_shawl_nudibranch_full_495.png 495w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_spanish_shawl_nudibranch/5941459-1-eng-US/mollusks_spanish_shawl_nudibranch_full_990.png 990w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_spanish_shawl_nudibranch/5941459-1-eng-US/mollusks_spanish_shawl_nudibranch_full_1468.png 1468w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_spanish_shawl_nudibranch/5941459-1-eng-US/mollusks_spanish_shawl_nudibranch_full_1980.png 1980w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_spanish_shawl_nudibranch/5941459-1-eng-US/mollusks_spanish_shawl_nudibranch_full_2475.png 2400w)
robust lancetooth
SCIENTIFIC NAME:
Haplotrema vancouverense
![Snail with golden shell](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_robust_lancetooth/5941455-1-eng-US/mollusks_robust_lancetooth_full_495.png 495w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_robust_lancetooth/5941455-1-eng-US/mollusks_robust_lancetooth_full_990.png 990w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_robust_lancetooth/5941455-1-eng-US/mollusks_robust_lancetooth_full_1468.png 1468w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_robust_lancetooth/5941455-1-eng-US/mollusks_robust_lancetooth_full_1980.png 1980w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_robust_lancetooth/5941455-1-eng-US/mollusks_robust_lancetooth_full_2475.png 2400w)
opalescent inshore squid
SCIENTIFIC NAME:
Doryteuthis opalescens
![Blue squid swimming](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_squid/5941463-1-eng-US/mollusks_squid_full_495.png 495w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_squid/5941463-1-eng-US/mollusks_squid_full_990.png 990w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_squid/5941463-1-eng-US/mollusks_squid_full_1468.png 1468w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_squid/5941463-1-eng-US/mollusks_squid_full_1980.png 1980w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_squid/5941463-1-eng-US/mollusks_squid_full_2475.png 2400w)
purple-ringed top snail
SCIENTIFIC NAME:
Calliostoma annulatum
![Purple and orange striped snail](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_purple_ringtop_snail/5941451-1-eng-US/mollusks_purple_ringtop_snail_full_495.png 495w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_purple_ringtop_snail/5941451-1-eng-US/mollusks_purple_ringtop_snail_full_990.png 990w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_purple_ringtop_snail/5941451-1-eng-US/mollusks_purple_ringtop_snail_full_1468.png 1468w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_purple_ringtop_snail/5941451-1-eng-US/mollusks_purple_ringtop_snail_full_1980.png 1800w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/biodiversity/tree-of-life/mollusks/mollusks_purple_ringtop_snail/5941451-1-eng-US/mollusks_purple_ringtop_snail_full_2475.png 1800w)
Guess what?
Some mollusks—like octopuses and slugs—don’t have shells.
Image Credits:
Chambered nautilus, © Orlando Bonney/CC BY-NC; cuttlefish, © Dr. Benjamin Titus/CC BY-NC; greater blue-ringed octopus, Courtesy of Roy Caldwell; opalescent inshore squid, purple-ringed top snail, Spanish shawl nudibranch, Courtesy of Gary McCarthy; robust lancetooth, © kholly/CC BY-NC; tidewater mucket, © Mike Jones/CC BY-NC.