Best described as “omnivorous detritivores” (Lancaster, 1988), hermit crabs are opportunistic in their feeding habits, which may be a contributor to their success inhabiting unpredictable, often extreme environments (Lancaster, 1988). Common food acquisition methods include filtering, deposit feeding, scrapping or scrubbing detritus from small and large surfaces, and even predation (Dunbar, 2002). Filter feeding often involves using modified “feathered antennae” to capture food from the water and transfer to the mouth (Dunbar, 2002). Alternately, the setae of the maxillipeds may also be used to filter suspended food material, which is then brushed toward the mouth (Lancaster, 1988). Deposit feeding involves using the chelipeds, and sometimes the walking legs, to “scoop” material to the hair covered 3rd maxillipeds (Dunbar, 2002; Lancaster, 1988). These “hairs” -the setae-  on these maxillipeds then act as a brush, transferring food material to the crabs mouth (Lancaster, 1988).  

While detritus is the main source of food and nutrients.  for hermit crabs (Hazlett, 1981), species including Birgus latro,  Gecarcinidae natalis and Cardiosoma hirtipes, among others (Dunbar, 2002) have also been known to predate upon much larger prey than themselves (Lancaster, 1988). Such prey includes ophiuroids, bivalves, amphipods and crangonids (Lancaster, 1988). Cannibalism has also been observed in some species including and includes smaller hermit crabs and sometimes even their own body parts that have been damaged, crushed  or completely removed (Lancaster, 1988).

In C. taeniatus , observations of gut contents of has revealed they mainly feed on soft detritus including decayed seagrass and its associated fauna and epiphytic algal flora (Kunze & Anderson, 1979). The abundance of epiphytes found in gut contents of C. taeniatus leads researchers to suggest that this is its preferred food over seagrass (Kunze & Anderson, 1979). In C. taeniatus,   epiphytes are collected by using the chelipeds to scrape surface of sea grass (Kunze and Anderson, 1979).  Macrophagous feeding on dead plant and animal material is not as common in C. taeniatus than in some other species of hermit crab (Kunze & Anderson, 1979).

Hermit crabs are generally very successful inhabitors of a wide range of habitat types including coral reef crests and flats, intertidal zones and rocky tide pool areas. C. taeniatus  however is found predominantly in both sandy and rocky intertidal, tide pool areas and mudflats (see Figure 4)  (Dunbar, 2002).

As one of the smaller species of hermit crab and as a result of its relatively exposed habitat, C. taeniatus is predominantly predated upon by birds, though in high tide these may extend to include elasmobranchs, octopus and some mantis shrimp and bony fish (Williams & McDermott, 2004). It is also thought that the feeding and reproductive strategies of some species of flatworms result in predatory behaviours on the eggs of hermit crabs (Williams & McDermott, 2004). These flatworms cement their egg masses to the inside of the host hermit crabs shell and have been confused with the gonadal mass of the hermit crab (Williams & McDermott, 2004). Though they aren’t thought to harm the brooding female host, these flatworms do reduce the reproductive potential as a result of this egg/embryo predation, but do no affect the males of the species (Williams & McDermott, 2004). 

Little research has been completed regarding the specific reproduction and development strategies of C. taeniatus, however the reproductive routine undertaken by copulating pairs of hermit crabs is generally consistent between species, with few variations. Furthermore, reproduction usually varies seasonally, though it can occur year round, and the peaks of reproduction seem to vary by magnitude depending on the latitude (Hazlett, 1981).

Like most decapods, hermit crabs including C. taeniatus are gonochoric, with two distinct sexes, although some may be hermaphroditic (Turra, 2004). Copulation is stimulated by female pheromones, resulting in males becoming more active and seeking out females (Shepherd & Edgar, 2013). Once a female is located, the male grasps the females shell with his walking legs and the pair engage in a brief foreplay before they both emerge from their shells (Shepherd & Edgar, 2013). Here the mating pair expose their ventral surfaces to one another, with the male on top, and the spermatophore is transferred to the female on her third or fourth pereiopod (see Figure 5) (Lancaster,  1988). Spawning occurs just hours after fertilisation and after exiting through the females gonophore, the developing embryos then move to the abdomen and attach to the females enlarged pleopods (Hess & Bauer, 2002). Females release their mature eggs into the water column by gently but repeatedly rocking the abdomen in and out of their shells, and the resulting larvae remain planktonic for a few weeks (Shepherd & Edgar, 2013).

Anomurans are characterised by having reduced fourth and fifth pairs of pereiopods, a second set of antennae outside of the eyestalks and by being carapace-free on the ventral side of the last thoracic plate (Lancaster, 1988). Unlike many other invertebrate taxa, hermit crabs and other decapods have exceptionally complex and numerous appendages, of which each order has specialised in a different manner. 

Figure 6 displays a median view of C. taeniatus from the right. The right-side coiling of the soft, unprotected abdomen is clear in this image, highlighting how vulnerable these animals are without their protective shells. The long uniramous antennae is also obvious, with the smaller, biramous antennulae visible in Figure 7, proximal to the antennae and compound eye stalks. The antennae contain a statocyst at their base and the nephridiopore (not pictured). The statocyst is hollow, and densely lined with mechanoreceptive cells, allowing the animal to sense its orientation as it moves, based on the earths gravitational pull (Ruppert, Fox & Barnes, 2004). The antennae are also often used to direct water currents for food collection and respiration. 

The first pair of pereiopods are enlarged, forming the chelipeds. They create a pincer, or a type of opposable fingers, with one side closing against the other to grab food, shells or a mate. Pereiopods two and three are uniramous, and used in the forward walking motion of anomurans. Chelipeds can sometimes also be used to aid walking. At the end of the coiled abdomen is the uropod, which forms a kind of hook when inside the shell to hold itself in place. Likewise, the reduced fourth pereiopod in Figure 7 is not normally visible when inside the shell and is covered in setae which both help keep itself in place when inside the shell. 

Figure 8 shows an alternate view of C. taeniatus, fully displaying the fused thoracic carapace. The branchiostegite (gill chamber) is also visible here, and a stylised version of the inside of the gill chambers can be viewed in Figure 10c. 

Finally, the mouthparts of C. taeniatus in Figure 9 shows the complexity of the feeding behaviours of hermit crabs. It requires these complex external mouthparts, maxillipeds, chelipeds and the internal proventriculus to all integrate functionally (Kunze & Anderson, 1979). While the degree of involvement of these complex parts differs, the importance of each is no less. Interestingly in C. taeniatus, the second and third walking pereiopods also help to stir up detrital layers, which their associated setae then collects. It is however more common for detrital material to be scooped up by the chelipeds and then transferred via the second and third maxillipeds to the inner mouth (Kunze & Anderson, 1979). The chelipeds are also commonly used to scrape epiphytic algae, thought to be C. taeniatus preferred food. While in larger individuals of C. taeniatus food material may be held to the mandibles and torn apart, it is more common for this species to take part in the more passive, sedentary mode of feeding (Kunze & Anderson, 1979). In this manner, when detritus and algae is abundant, they will rest their shell on the substrate and use just their third maxillipeds to collect food (Kunze & Anderson, 1979). The endopods of these appendages are rapidly flexed in no particular pattern to shift the food matter towards the first and second maxillipeds, where the food material is sorted and then ingested (Kunze & Anderson, 1979).

Unlike most other invertebrates, decapods have a very well developed hemal system which comprises a heart, well-developed arterial system as well as capillaries and venous sinuses (Ruppert, Fox & Barnes, 2004). The heart has evolved from its primitive tubular morphology, and comprises a rectangular sac in the thorax (Ruppert, Fox & Barnes, 2004). Though it consists of a single chamber, its location, suspended in the pericardial cavity, acts as a second chamber (; McMahon & Burnett, 1990).  Since this system is an open system there is no direct venous return of hemolymph, instead it returns to the pericardial cavity, where three paired ostia return the hemolymph back to the heart. (McMahon & Burnett, 1990). Scientists have estimated complete circulation in large decapods to take just 40 to 60 seconds total (Ruppert, Fox & Barnes, 2004). Though relatively simple in design, this system is able to regulate and control the flow of hemolymph between all organs and tissue beds, in addition to providing the role of the lymphatic system (Ruppert, Fox & Barnes, 2004).

While most decapods are able to excrete nitrogenous waste across their highly permeable gill epithelia, their hemolymph coelomic cavity also allows the possession of a single excretory pore (Ruppert, Fox & Barnes, 2004). These are known as antennal glands, and are located at the base of the second antennae. This gland, the nephridiopore, is connected to a proximal labyrinth, which maintains the bloods ionic balance. This in turn is connected to a distal bladder, which stores urine and has a short duct connecting it directly to the nephridiopore for excretion (Ruppert, Fox & Barnes, 2004). 

In decapods, up to 24 pairs of gills associated with the thoracic appendages provide the gas exchange requirements (Ruppert, Fox & Barnes, 2004). The gills are very well perfused and highly permeable due to the very thin gill cuticle surrounding them. This leave the gills highly permeable to both the gases required for respiration, but also to a variety of other materials and ions that may be present in the water (Ruppert, Fox & Barnes, 2004). As with all crabs, the water enters the gill chambers at the base of the chelipeds (Ruppert, Fox & Barnes, 2004). The setae located at the base of the chelipeds filters the incoming sea water, removing sediment from the flow, before moving through to the gill chambers via a current created by the gill bailer (See Figure 10a and 10c) (Ruppert, Fox & Barnes, 2004). The gill bailer is paddle-like, beating to form the current, directing the incoming water to flow lateral across the gill filaments, then exiting through the exhaling apertures  via an anterior flow (Ruppert, Fox & Barnes, 2004). The passage of water through the gill chamber follows a U shape (see Figure 10b). In decapods like C. taeniatus,  the three elongated epiopods of the maxillipeds sweep the gill filaments, cleaning them of foreign particles to maximise the countercurrent oxygen exchange (Ruppert, Fox & Barnes, 2004).