updated Oct 13
learn only 3 things about them ...
This hermit crab is seldom seen on the mainland.
Every empty shell is a potential hermit crab home. Don't
take any shells home!
is so well adapted to land it will drown if kept under
This large hermit crab is sometimes seen on our undisturbed shores
near the high water line, especially on our offshore islands. Near
the high water mark among rocks, boulders and marine debris, and even
some distance inland among grass and under trees. But it is only active
Features: Boday 3-6cm long, 1cm
wide. Left pincer usually larger than the right. Pincers and walking
legs "squarish" thick, not very hairy. May be brownish to
pale or dark purple. Eyes on very short flattened stalks. Short antennae
quite long, while long antennae not very long.
There are three species of land hermit crabs in Singapore. They are not easy to distinguish in the field.
The Land hermit crab is so well adapted to life out of water that
it will drown if kept underwater! It has special gill chambers that
act as lungs. These chambers are large and holds water to keep the
gill filaments wet. The hermit crab only needs to occasionally dip
in either rainwater or the sea to keep the chambers wet. Females,
however, must go to the edge of the sea to release their eggs into
the sea. These hatch into planktonic larvae. When the larvae develops
into a small hermit crab, it finds an empty shell then heads landward.
The Family Coenobitidae includes the largest hermit crab, the Robber
or Coconut crab (Birgus latro) which doesn't live in a shell.
What does it eat? The hermit crab
is a scavenger and also eats plants. It may go far inland to forage.
Sometimes, many are seen at night near the visitors' huts on our offshore
islands. Possibly looking for scraps left behind by visitors?
Shells not enough? Often, those
seen are found in shells that are too small for the animal. The poor
hermit crab often can't retract all the way into the shell, and a
part of it is still sticking out. This is possibly because high up
on the shore, there aren't enough empty shells that are suitably large.
The lack of suitably large shells on our shores may limit the population
of these amazing animals. The land hermit crab is now considered rare
on mainland Singapore.
Status and threats: Our land hermit
crabs are listed as 'Vulnerable' on the Red List of threatened animals
of Singapore. Singapore's more accessible beaches are regularly cleaned
of any debris that washes up on the high tide mark. But this is where
land hermit crabs find shelter, food and new shells. Deprived of their
habitat, these endearing animals are no longer commonly encountered
on our beaches.
According to the Singapore Red Data Book, the many beach improvement
schemes, clearance of 'unsightly' natural beach vegetation have almost
exterminated these once common animals. Well-intentioned beach clean
up have also resulted in mass removal of seemingly empty shells containing
Some are very purple.
St. John's Island, Aug 08
Some have a dark patch on the
outside of the left pincer.
Sisters Islands, Jan 05
hermit crabs on Singapore shores
Pulau Jong, Apr 11
Photo shared by Russel Low on facebook.
Pulau Jong, Apr 15
Photo shared by Marcus Ng on facebook.
Lazarus Island, Feb 11
shared by Rene Ong on facebook.
Pulau Pawai, Dec 09
|Family Coenobitidae recorded for Singapore
Dwi Listyo Rahayu, 2000. Hermit crabs from the South China Sea (Crustacea:
Decapoda: Anomura: Diogenidae, Paguridae, Parapaguridae)
in red are those listed among the threatened
animals of Singapore from Davison, G.W. H. and P. K. L. Ng
and Ho Hua Chew, 2008. The Singapore Red Data Book: Threatened
plants and animals of Singapore.
+Other additions (Singapore Biodiversity Records, etc)
||Coenobita sp. (Land hermit crabs)
Coenobita cavipes (VU:Vulnerable)
Coenobita violascens (VU:Vulnerable)
- D. L. Rahayu, H.-T. Shih & P. K. L. Ng. 29 June 2016. A new species of land hermit crab in the genus Coenobita Latreille, 1829 from Singapore, Malaysia and Indonesia, previously confused with C. cavipes Stimpson, 1858 (Crustacea: Decapoda: Anomura: Coenobitidae). The Raffles Bulletin of Zoology 2016 Supplement No. 34 (Part I of II) Pp. 470-488.
G.W. H. and P. K. L. Ng and Ho Hua Chew, 2008. The Singapore
Red Data Book: Threatened plants and animals of Singapore.
Nature Society (Singapore). 285 pp.
- Lim, S.,
P. Ng, L. Tan, & W. Y. Chin, 1994. Rhythm of the Sea: The Life
and Times of Labrador Beach. Division of Biology, School of
Science, Nanyang Technological University & Department of Zoology,
the National University of Singapore. 160 pp.
- Jones Diana
S. and Gary J. Morgan, 2002. A Field Guide to Crustaceans of
Australian Waters. Reed New Holland. 224 pp.