James Powell jpowell at
Wed Oct 15 10:05:05 EDT 1997

The following is a message and questions that I received concerning land and
hermit crabs. Can anyone answer these questions or point me in the direction
of an authority that I might contact?

Thank you,
James Powell
Glovers Reef Marine Research Station


I recently visited Half Moon Caye as a guest of the Belize Audubon Society
to advise on the possibility of eradicating rats from that island.  Rat
eradication is certainly possible and the benefits would be enormous.  There
are, however, a few things that should be learned before an eradication
project can start.  Bruce Miller advises me that you may be able to help.

Land crabs (Cardisoma guanhumi) and hermit crabs (Coenobita clypeatus) are
both present on HMC and both present possible problems for rat eradication.
Can you advise me on aspects of the biology of these species?

The land crabs appeared to be present as only one age class - all adults
about 100mm accross the back.  What is the life span of this species?  When
do they spawn?  When do their young come ashore?  What size are they at that
time?  I presume that these young crabs would be a significant food source
for rats - right or wrong?  Where and how often do these crabs change their
shells and how vulnerable would they be to rats at that time?

The hermit crabs were present in all sizes but the relative abundance of
young and old suggests that the young of this species are also preyed on by
rats.  What is the life span of this species?  When do they spawn?  When do
their young come ashore?  What size shell are they carrying when they come
ashore?  Am I right in presuming that rats could easily eat them at this time?


Dick Veitch

48 Manse Road
New Zealand
Phone 064-9-298 5775

Department of Conservation
Private Bag 68 908
New Zealand
Phone 064 9 307 9279
Fax 064 9 377 2919

James A. Powell
Glovers Reef Marine Research Station
Wildlife Conservation Society
P.O. Box 2310
Belize City, Belize
Tel/Fax 501-233855
Middle Caye: 501-522153
e-mail: jpowell at

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