Tag Archive for breathing

Airborne Irritants and Hermit Crabs

Hermit crab's gills are sensitive to airborne irritants

Hermit crab’s gills are sensitive to airborne irritants

Land hermit crabs breathe through a modified gill. It is important to protect the gills from strong fragrances, essential oils, candles, household cleaners, chemicals, smoke insecticides and other airborne irritants.

Be mindful of what you spray or use near the crabitat even if your tank is fully sealed. Residual product may still be in the air when you open your tank.

If you are forced to have your home sprayed for insects ensure your tank is fully sealed with saran wrap or something similar. Allow the house to air out at least 24 hours before unsealing your tank.

Coenobita respiration

Gills

A hermit crab’s gills are enclosed in the branchial chamber, which functions as a lung. The branchial chamber is on the sides of the thorax, above the crab’s legs. A hermit crab breathes through its gills and branchial chamber, which must be kept moist in order to function. If the branchial chamber and gills dry out, the crab will die. Compared to aquatic crabs, land hermit crab’s gills are reduced in size, and if the adults are kept underwater too long, they will drown. [2]

There are tufts of setae at various sites on the ventral surface that enable moisture from the substrate to be passed to the branchial chamber. [1]

Maintaining the correct relative humidity inside the crabitat is crucial to survival. Without sufficiently humid air your hermit crabs will slowly suffocate and die. Once the gills are damaged from too dry air they can not repair themselves.

Unless you live in a native climate and do not use any form of heat or air conditioning your crabitat will require a lid to maintain the correct humidity levels. Your house is likely 40-50% relative humidity.

A hermit crab requires 70-80% relative humidity. This range is for the purple pincher hermit crab (Coenobita clypeatus) native to Florida and the Caribbean. Other species of land hermit crabs enjoy a slightly higher relative humidity of 85%. You will need a solid lid for the crabitat (tank or aquarium) and a good quality hygrometer and thermometer to accurately measure the air inside of the crabitat.

All hygrometers should be calibrated prior to use.

Different ways to create humidity in your hermit crab habitat.

This tank is set up correctly with solid glass lids.


Humidity levels maintained above 85% are not harmful to the hermit crab directly but can lead to an unsafe environment in the crabitat. Floods, excessive surface mold and mildew, slime mold and bacterial blooms are just of the unsafe conditions that can develop from maintaining excess humidity levels.

Treat your hermit crab in the same manner you would treat a fish and refrain from removing them from their humid environment unless absolutely necessary. A very brief photo from time to time is acceptable. Taking your hermit crab from the tank on a regular basis (for any purpose) is strongly discouraged.

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References:
1. Biology of the Land Crabs Warren W. Burggren and Brain R. McMahon
2. Hermit crabs : everything about anatomy, ecology, purchasing, feeding, housing, behavior, and illness Sue Fox

Central Heating and Air Conditioning

Coenobita Gills

The gills of Coenobita and Birgus are modified for air-breathing but are reduced in number and size and have a comparatively small surface area. The branchiostegal lungs of Coenobita (which live in gastropod shells) are very small but are well vascularized and have a thin blood/gas barrier. Coenobita has developed a third respiratory organ, the abdominal lung, that is formed from highly vascularized patches of very thin and intensely-folded dorsal integument. Oxygenated blood from this respiratory surface is returned to the pericardial sinus via the gills (in parallel to the branchiostegal circulation). Birgus, which does not inhabit a gastropod shell, has developed a highly complex branchiostegal lung that is expanded laterally and evaginated to increase surface area. The blood/gas diffusion distance is short and oxygenated blood is returned directly to the pericardium via pulmonary veins. We conclude that the presence of a protective mollusc shell in the terrestrial hermit crabs has favoured the evolution of an abdominal lung and in its absence a branchiostegal lung has been developed. [1]

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Overview of the anatomy of a land hermit crab (Coenobita)

References:
1 The morphology and vasculature of the respiratory organs of terrestrial hermit crabs (Coenobita and Birgus): gills, branchiostegal lungs and abdominal lungs
C.A. Farrellya, P. Greenawayb, ,
a 32 Tramway Pde. Beaumaris, Vic. 3193, Australia
b School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, N.S.W. 2052, Australia