Light-blue soldier crab
Mictyris longicarpus
- Usual depth1–1 m
- Water temperature18–29 °C
- Best monthsMarch, April, and May
- How commonOccasional
Photo credit: (c) User:LiquidGhoul, some rights reserved (CC BY-SA) · CC BY-SA · iNaturalist
About this species
Mictyris longicarpus, the light-blue soldier crab, is a species of crab that lives on sandy beaches from the Bay of Bengal to Australia; with other members of the genus Mictyris, it is "one of the most loved crabs in Australia". Adults are 25 mm (1 in) across, white, with blue on their backs, and hold their claws vertically. They feed on detritus in the sand, leaving rounded pellets of discarded sand behind them. The males may form into large "armies" which traverse the beach at low tide, before the crabs dig into the sand to wait for the next low tide.
Text from the Wikipedia article “Mictyris longicarpus”, licensed CC BY-SA 4.0. Read the article
Where and when
Where it has been recorded
Worldwide
Loading the map
Best months
Worldwide (open data)
- January: 175 records
- February: 173 records
- March: 186 records
- April: 269 records
- May: 188 records
- June: 167 records
- July: 182 records
- August: 151 records
- September: 142 records
- October: 127 records
- November: 107 records
- December: 122 records
Depth and water temperature
Depth
Mostly recorded at 1–1 m · Deepest record: 1 m
Water temperature
Recorded in surface water of 18–29 °C
Photos
no rights reserved · CC0 1.0 · iNaturalist 
(c) Daniel Eisenhauer, some rights reserved (CC BY) · CC BY · iNaturalist 
(c) Auradyme, some rights reserved (CC BY) · CC BY · iNaturalist 
(c) Daniel Eisenhauer, some rights reserved (CC BY) · CC BY · iNaturalist 
(c) Thomas Mesaglio, some rights reserved (CC BY) · CC BY · iNaturalist 
(c) Roman Soroka, some rights reserved (CC BY) · CC BY · iNaturalist 
(c) Zoe Anthony Quested, some rights reserved (CC BY) · CC BY · iNaturalist
Names and classification
- English
- Light-blue soldier crab, light-blue soldier crab
Names in 2 more languages
- German
- Hellblaue Grenadierkrabbe, Hellblaue Regimentskrabbe, Hellblaue Soldatenkrabbe
- French
- Mictyre longicarpe (Le)
Other scientific names: Myctiris longicarpus, Ocypode (Mictyris) deflexifrons
Similar species
Dark blue soldier crabMictyris platycheles
Sources and credits
Names and taxonomy: WoRMS (CC BY 4.0) and the GBIF Backbone (CC BY 4.0). Photos: iNaturalist observers, each under the licence shown (CC0, CC BY or CC BY-SA).
- Depth, temperature, months and maps: records from OBIS and GBIF under CC0 or CC BY.
- Descriptions: Wikipedia, licensed CC BY-SA, each linked to its article.
- Conservation status as published by GBIF (IUCN Red List).
- 527 open-data records from 1806 to 2010.
- Species data updated November 4, 2026.
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