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Best match-ups for Coconut Crab?
Topic Started: Mar 25 2016, 09:50 PM (1,740 Views)
Vivyx
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I recently requested a Coconut Crab v Fisher match-up which was made for me, and I do think it's fairly close, but I'm trying to think of another idea for a match-up with one. Got any ideas?
Edited by Vivyx, Mar 25 2016, 09:50 PM.
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Shin
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how bout a rock monitor?
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Ceratodromeus
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ceph posted this data in the coconut crab v gold tegu thread, it may be helpful in deciding opponents!
Ceph
Sep 22 2015, 01:55 AM
Posted Image

Posted Image

Mature Crabs of Moderate Size—This stage includes the crabs with TL between
approximately 25 mm (the onset of sexual maturity) and approximately 52 mm (the maximum
female size). Crabs within this stage are the source of the eggs and larvae which allow the
population to reproduce itself. The rate of reproduction during this stage is presumably
influenced by food availability, sex ratios, crab density, and access to the ocean. Possible sources
of mortality during this stage are starvation, disease, predation (which is probably less severe
during this stage than during the previous stage when crabs are smaller), cannibalism and fatal
intraspecific encounters (which may be high if density is high and food or appropriate burrow
sites are limited), and human harvesting. The duration of this stage is not known.

Large Male Crabs—Large males in excess of 52 mm TL may not be reproductively active
in natural coconut crab populations (Helfman, 1973). Because of their large size, they are
probably not subject to natural predation. Mortality is most likely caused by disease, starvation,
fatal intraspecific encounters, and human harvesting. These large crabs are the most sought-after
crabs for food. Helfman (1973) has suggested that these large male crabs may inhibit the crabs
of reproductive size, excluding them from potential burrow sites, competing with them for food,
and attacking and killing them. This has not been clearly demonstrated, however, and on
Asuncion and Guguan, which had the highest density of large male crabs seen during this study,
the proportion of reproductively active females observed was also very high.

http://guammarinelab.com/publications/uogmltechrep66.pdf

BIOLOGICAL STUDIES
ON THE COCONUT CRAB (BIRGUS LATRO)
IN THE MARIANA ISLANDS
Steven S. Amesbury
Agriculture Experiment Station
College of Agriculture and Life Sciences
University of Guam
Technical Report No. 17
University of Guam
Marine Laboratory
Technical Report No. 66
December 1980
[Reprinted December 2000]


Quote:
 
The regression equation was calculated on log transformed data using Bartlett's Three
Group Method (Sokal and Rohlf, 1969). Males and females were combined in the calculation as
no consistent differences, other than the narrower range of sizes of the females, were observed
between the two sexes. The resulting equation is
W = .0077 TL3.0008 (weight in g, thoracic length in mm);
the plotted points are shown in Fig. 7. The exponent, 3.0008, is very close to 3 and indicates that
the crabs are growing isometrically, with no change in shape or specific gravity with increasing
size. The weights at the upper end of the distribution tend to be slightly greater than the
regression line predictions. This may be a result of weight measurement errors, as all of these
points were measured in the field with the least sensitive of the spring balances.
from a more recent study

Posted Image

Posted Image

Posted Image

Posted Image

http://www.zianet.com/tedmorris/dg/2005nrmp-appendixg-coconutcrabsurveys.pdf
Coconut Crab (Birgus Latro) Survey on
Diego Garcia
Prepared by
Mr. Scott Vogt
NAVFAC Pacific
September 2004
Chauvet, C. and T. Kadiri-Jan. 1999. Assessment of an unexploited population of
coconut crabs, Birgus latro (Lenni’, 1767) on Taiaro atoll (Tuamotu archipelago, French
Polynesia). Coral Reefs (1999) 18:297-299.
Kadiri-Jan T. 1995. Biology and population dynamic of the coconut crab (Birgus latro)in
Loyalty islanad. New Caledonia. Theses of Universite’ Francaise du Pacifique New
Caledonia: 155pp.
USFWS. 2001. Assessment of the coconut crab (Birgus Latro) population on the Naval
computer and telecommunications master station. Prepared for: Department of the Navy,
Environmental Section, Commander U.S. Naval Forces, Marianas. Prepared by: U.S.
Fish and Wildlife Service, Guam National Wildlife Refuge, Dededo Guam.

So, 500g does seem to be about average, at least for these populations. These little specimens have no place in a match with a reptile ten times their size. Top end male specimens maybe the best route to a viable match here.
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Vivyx
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Ceratodromeus
Mar 26 2016, 01:44 AM
ceph posted this data in the coconut crab v gold tegu thread, it may be helpful in deciding opponents!
Ceph
Sep 22 2015, 01:55 AM
Posted Image

Posted Image

Mature Crabs of Moderate Size—This stage includes the crabs with TL between
approximately 25 mm (the onset of sexual maturity) and approximately 52 mm (the maximum
female size). Crabs within this stage are the source of the eggs and larvae which allow the
population to reproduce itself. The rate of reproduction during this stage is presumably
influenced by food availability, sex ratios, crab density, and access to the ocean. Possible sources
of mortality during this stage are starvation, disease, predation (which is probably less severe
during this stage than during the previous stage when crabs are smaller), cannibalism and fatal
intraspecific encounters (which may be high if density is high and food or appropriate burrow
sites are limited), and human harvesting. The duration of this stage is not known.

Large Male Crabs—Large males in excess of 52 mm TL may not be reproductively active
in natural coconut crab populations (Helfman, 1973). Because of their large size, they are
probably not subject to natural predation. Mortality is most likely caused by disease, starvation,
fatal intraspecific encounters, and human harvesting. These large crabs are the most sought-after
crabs for food. Helfman (1973) has suggested that these large male crabs may inhibit the crabs
of reproductive size, excluding them from potential burrow sites, competing with them for food,
and attacking and killing them. This has not been clearly demonstrated, however, and on
Asuncion and Guguan, which had the highest density of large male crabs seen during this study,
the proportion of reproductively active females observed was also very high.

http://guammarinelab.com/publications/uogmltechrep66.pdf

BIOLOGICAL STUDIES
ON THE COCONUT CRAB (BIRGUS LATRO)
IN THE MARIANA ISLANDS
Steven S. Amesbury
Agriculture Experiment Station
College of Agriculture and Life Sciences
University of Guam
Technical Report No. 17
University of Guam
Marine Laboratory
Technical Report No. 66
December 1980
[Reprinted December 2000]


Quote:
 
The regression equation was calculated on log transformed data using Bartlett's Three
Group Method (Sokal and Rohlf, 1969). Males and females were combined in the calculation as
no consistent differences, other than the narrower range of sizes of the females, were observed
between the two sexes. The resulting equation is
W = .0077 TL3.0008 (weight in g, thoracic length in mm);
the plotted points are shown in Fig. 7. The exponent, 3.0008, is very close to 3 and indicates that
the crabs are growing isometrically, with no change in shape or specific gravity with increasing
size. The weights at the upper end of the distribution tend to be slightly greater than the
regression line predictions. This may be a result of weight measurement errors, as all of these
points were measured in the field with the least sensitive of the spring balances.
from a more recent study

Posted Image

Posted Image

Posted Image

Posted Image

http://www.zianet.com/tedmorris/dg/2005nrmp-appendixg-coconutcrabsurveys.pdf
Coconut Crab (Birgus Latro) Survey on
Diego Garcia
Prepared by
Mr. Scott Vogt
NAVFAC Pacific
September 2004
Chauvet, C. and T. Kadiri-Jan. 1999. Assessment of an unexploited population of
coconut crabs, Birgus latro (Lenni’, 1767) on Taiaro atoll (Tuamotu archipelago, French
Polynesia). Coral Reefs (1999) 18:297-299.
Kadiri-Jan T. 1995. Biology and population dynamic of the coconut crab (Birgus latro)in
Loyalty islanad. New Caledonia. Theses of Universite’ Francaise du Pacifique New
Caledonia: 155pp.
USFWS. 2001. Assessment of the coconut crab (Birgus Latro) population on the Naval
computer and telecommunications master station. Prepared for: Department of the Navy,
Environmental Section, Commander U.S. Naval Forces, Marianas. Prepared by: U.S.
Fish and Wildlife Service, Guam National Wildlife Refuge, Dededo Guam.

So, 500g does seem to be about average, at least for these populations. These little specimens have no place in a match with a reptile ten times their size. Top end male specimens maybe the best route to a viable match here.
I was aware of those studies, but I was rather thinking of opponents for the coconut crab at a size range of around 4 kg. I think that it seems a bit easier to think of actual opponents that can actually physically hurt it more than animals of around the 500 g range, as I would expect opponents like mustelids and birds of prey in the 500 g range to be quite fragile. Also, I don't really feel like running along the threads that the Coconut Crab already is in, posting the studies and just saying mismatch. But I'm not really sure for a match-up of a 500 g coconut crab, maybe a brown rat or some stoat?
Edited by Vivyx, Mar 26 2016, 02:02 AM.
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Ceratodromeus
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my bad just saw your comments in some coconut crab matches lol

shin's suggestion would work probably, if you're speaking only the larger male crabs and not average adults
Edited by Ceratodromeus, Mar 26 2016, 05:27 AM.
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thegrackle
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Shin
Mar 26 2016, 12:22 AM
how bout a rock monitor?
I was going to say a crab-eating raccoon or crab-eating fox, but I think that a coconut crab vs. rock monitor thread would be good a good thread.
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Koh-i-Noor
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Maybe some type of constrictor.
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Vivyx
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Would an Oriental Small-clawed Otter or some other kind of otter similar in size to it be alright?

---

Idea of a crab-eating fox could be potentially quite interesting.

I have to say that I think a coconut crab v constrictor match could end up looking quite weird, but I think it would end up with the crab getting a good hold of the neck or head. I can't really see a very effective way that a similar-sized constrictor can kill a very tough crab like this, constriction on an armoured opponent would take some time to kill it..
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Vivyx
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How does a Brazilian Porcupine (Coendou prehensilis) v Coconut Crab (Birgus latro) thread sound?

nvm, bad idea.
Edited by Vivyx, Feb 12 2017, 03:28 AM.
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Taipan
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Vivyx
Feb 11 2017, 11:11 PM
How does a Brazilian Porcupine (Coendou prehensilis) v Coconut Crab (Birgus latro) thread sound?


What could a porcupine do? They are defensive animals, and the Brazilian species cant effectively use its tail (its spineless).

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Vivyx
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I guess that the porcupine could conceivably target some vulnerable areas of the crab (like the eyes or the joints between the legs) using the superior manoeuvrability it has as well as the rather formidable teeth it has which are characteristic to rodents, but I guess you're right in taking in the fact that the coconut crab might be too well-armoured. I just thought that it would be interesting to see a match-up involving two well-armoured animals.




Maybe Nimbacinus dicksoni could be interesting? Or a bush dog?
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Nergigante
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What about a yellow-bellied marmot?
Edited by Nergigante, Feb 12 2017, 01:33 AM.
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Ceph
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I think marmots would would be in the same boat as porcupines. They aren't well equipped to deal with such a heavily armored opponent. It would take a significant prey drive to motivate an animal to chew through the robbers armor. The best mammalian matches in my opinion would mustalids. Speed and tenacity would balance well against armor and powerful claws. If we are truly seeking a rodent, maybe a large aggressive species of rat against a average coconut crab.
Edited by Ceph, Feb 12 2017, 02:02 AM.
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Vivyx
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Actually, if the information given by Ceph about the average weight of the coconut crab is true then I think that some sort of small mustelid would be a very interesting match-up. Maybe an American Mink?

Brown Rat or Gambian Pouched Rat could be a good rodent opponent (rhyme intentional).
So how do you guys feel about American Mink (Neovison vison) v Coconut Crab (Birgus latro)? Might request that soon enough.
Edited by Vivyx, Feb 13 2017, 10:17 AM.
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ImperialDino
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Coconut Crabs vs Snapping Turtle!
Coconut Crab vs Tasmanian Devil
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