1
Japanese spider crab
Leg span: 4m
Distribution: Pacific Ocean around southern Japan
2
American lobster
Length: 1m
Distribution: Atlantic Ocean around North America
3
Coconut crab
Leg span: 1m
Distribution: Indian Ocean and Central Pacific Ocean
4
Tasmanian monster crab
Leg span: 80cm
Distribution: Oceans off southern Australia
5
Tasmanian giant freshwater crayfish
Distribution: Rivers and streams in Tasmania
6
Zebra mantis shrimp
Length: 40cm
Distribution: Indo-Pacific region
7
Alicella gigantea
Length: 34cm
Distribution: Kermadec Trench, New Zealand
8
Giant tiger prawn
Length: 33cm
Distribution: Indian Ocean and West Pacific
9
Giant acorn barnacle
Length: 30cm
Distribution: Coast of northwest America
10
Euphausiid (krill)
Length: 15cm
Distribution: Antarctic Ocean
Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun science facts.