The majority of bigclaw snapping shrimp populations are found on the bottom in subtidal waters, to a depth of 30 meters or more. They hide or burrow under rocks and shells for protection during the day, and are common on oyster reefs. Bigclaw snapping shrimp have a wide tolerance of salinity concentrations, inhabiting waters that range from mesohaline (5-18 ppt) to hyperhaline (>40 ppt) salinities. Shallow waters, particularly those where rocks, seaweed, and other cover is present, are where these shrimp are usually found. (Kaplan, 1999; McClure, 1995)
The bigclaw snapping shrimp is the largest of all the snapping shrimp. The average adult length measured from rostrum to tail end ranges from 3.0 cm to 5.5 cm, but some adults may only grow to be 10 mm in length. Both males and females mature to the same approximate size, and the only sexually dimorphic trait is that the snapping claw of the male is slightly larger than that of the female.
It has three pairs of legs, two sets of antennae, and two claws: a modified snapping claw and an unmodified claw. The side on which the modified claw is found is not specific. Both claws are covered in setae.
By far the most defining trait of bigclaw snapping shrimp is their large, modified snapping pincer. The modified claw is capable of being cocked by opening the claw. This locks the smaller digit of the pincer open by wedging it behind a “shelf” between the digits of the pincer. This pincer can be "fired" by both digits snapping together. This modified pincer occurs only in adult shrimp.
The coloration of the bigclaw snapping shrimp ranges from dark blue-green to gray. Most shrimp have concentrations of orange on the top of the head behind the eyes, at the tip of the tail, and on the larger, modified claw. Their entire body is speckled with darker gray-brown spots, and much of their body is translucent. (Gross and Knowlton, 1999; Herberholz and Schmitz, 1998b; Herberholz and Schmitz, 1999; Hughes, 1996a; McClure, 1995)
After fertilization, the eggs gestate for approximately 28 days and then hatch. After hatching, bigclaw snapping shrimp enter a larval development cycle of metamorphosis consisting of three larval stages. The first stage lasts only 1-2 hours during which enlargement of the organism occurs. Some shrimp are hatched at a large enough body size to begin the second larval stage, skipping the entire first larval stage because it is unnecessary for development. The second larval stage lasts 28 hours and serves to further develop the eyes and appendages of the shrimp. The third and final stage of larval development lasts approximately 2-3 days. No information on the details of development during the third larval stage could be found. Bigclaw snapping shrimp molt their exoskeletons during larval development. The time of molting depends on the rate of growth of each individual larva. After the third stage of larval development, bigclaw snapping shrimp enter the post-larval stage and resemble adult shrimp without the modified pincer. Until the post-larval stage occurs and functional mouthparts are formed, the larvae feed completely on egg yolk and oil reserves. (Gross and Knowlton, 1999; Gross and Knowlton, 2002; Knowlton, 1973; Spence and Knowlton, 2008)
Bigclaw snapping shrimp, like most other snapping shrimp, are monogamous, with the reproduction cycle directly related to the molt cycle of the female shrimp. There is a brief period of a few hours directly after the female molts during which they are sexually receptive. Chemical signals and “firings” of the modified pincer are the chemosensory and mechanosensory messengers that signal when this mating window will open. Their monogamous longevity is uncertain, but most shrimp (~65%) captured in a study by Nolan and Salmon (1970) were in male-female pairs. (Hughes, 1996a; Nolan and Salmon, 1970; Schein, 1975)
Relations of male-female pairs in bigclaw snapping shrimp often begin in a similar manner as territorial interactions between alpheid shrimp. Interactions usually begin with aggressive warning snaps produced by the modified pincer until it is determined by both shrimp that they are interacting with a member of the opposite sex. The male-female pair will then mate at the appropriate time in the female’s molt cycle. This time usually occurs every 3 to 5 weeks. Between mating times, the male provides protection for the female when she molts and sheds her protective outer covering. This type of male-female pairing benefits the male by allowing access to the maximum number of mating opportunities and benefits the female by making it unnecessary to search for a mate while in her vulnerable molting state. Chemical signals are expected to also play a role in identifying unpaired shrimp. Although bigclaw snapping shrimp are known to be sexually mature after their post-larval stage, an exact time to reproductive maturity has not been studied. (Herberholz and Schmitz, 1998b; Mathews, 2002; Schein, 1975)
Bigclaw snapping shrimp eggs and larvae are predominately cared for by the males. Though the female shrimp is never absent during the larval development of the hatchling shrimp, male shrimp are more aggressive territorial defenders than female shrimp, and this territoriality causes the males to be more protective of the developing larvae. After 4-5 days, larvae are fully formed and parental protection and care ceases. (Mathews, 2002; Schein, 1975)
Bigclaw snapping shrimp can live as long as 4 years in the wild. When kept as pets, these shrimp live an average of 2-3 years. In the wild they have a high rate of larval mortality, as do most shrimp, but the chance of survival increases with age.
In studies of the mutualistic relationship between bigclaw snapping shrimp and Cryptocentrus cryptocentrus (ninebar prawn-goby), shrimp in goby-shrimp pairs tend to live longer than shrimp that are not paired with a goby. (Kaplan, 1999; Karpulus, et al., 1972; Knowlton, 1973)
Bigclaw snapping shrimp are a very territorial species of snapping shrimp with many means of exhibiting territorial defense. Frequently having adjacent territories, territorial intrusions occur quite often. When these interactions occur, they usually begin with a faceoff period between the defending male and the intruding shrimp, whether it be a male or female. During this face-off, the antennae of the animals touch and both animals snap their modified pincer. After this initial faceoff, if the interaction is between two males or a defending male currently belonging to a male-female pair and an intruding female, one of the shrimp will become the dominant and the subservient shrimp will retreat. If the interaction is between an unpaired male and unpaired female shrimp, they will often form a monogamous pair. Once dominance has been asserted, the subservient shrimp, if it was the intruder, will retreat back to its original territory; if it was the defending shrimp, it will retreat to find a new territory. These same interactions occur over the protection of mates and eggs or larvae. Chemical signals are also used to mark territory and warn against intruders.
The most well-known and studied behavior of bigclaw snapping shrimp is their ability to create loud "pops" with their modified pistol claw. These "pops" are used in communication and during the hunting of prey. This phenomenon is accomplished by the physical process of cavitation, the rapid formation and implosion of cavities in a liquid in which the pressure of the liquid falls below its vapor pressure. The study by Versluis et al. (2000) was the first to describe the physics behind this extraordinary ability. The rapid firing of the modified pincer causes a high-velocity water jet. This water jet exceeds speeds needed for cavitation to occur and causes a very small and very brief bubble to form and implode within an incredibly short time (less than 300 μs). A study by Lohse et alia (2001) found that as the bubbles formed by the water jets collapsed, they emitted an intense flash of light. From this they concluded that at the time of the collapse of the cavitations, extremely high pressures (unmeasured) and temperatures (above 5000 °C) occur. These high pressures and temperatures are the cause of the ability to stun prey or even kill them if they are within a few millimeters of the tip of the snapping claw. (Herberholz and Schmitz, 1998a; Herberholz and Schmitz, 1998b; Herberholz and Schmitz, 1999; Herberholz and Schmitz, 2001; Hughes, 1996b; Hughes, 1996a; Lohse, et al., 2001; Nolan and Salmon, 1970; Schein, 1975; Versluis, et al., 2000)
Bigclaw snapping shrimp occupy small areas of seabed that are often adjacent to the territories of other bigclaw snapping shrimp. No studies have been conducted on the exact size of the area a single shrimp utilizes. (Hughes, 1996b; Hughes, 1996a; Schein, 1975)
To date, no auditory organs have been discovered in bigclaw snapping shrimp. For this reason, it is believed that mechanosensory and chemosensory reception are the primary forms of perception in this organism. These types of perceptions are particularly important for use in conspecific communication.
The primary means of communication used by bigclaw snapping shirmp is the modified pistol claw. They use both the snap frequency and the speed of the water jet produced by the snap to receive or transmit information. It has even been suggested by Herberholz and Schmitz (1998) that bigclaw snapping shrimp receiving signals from the claws of other shrimp can detect the sex of the transmitter due to the fact the males produce more “aggressive” snap frequencies and jet speeds. In a similar study, it was found that sex can also be perceived over longer distances (>30 meters) by the reception of gender-specific chemical signals.
The aggressions of bigclaw snapping shrimp toward members of the same species are also expressed with the modified pistol claw. These aggressive interactions are often a result of intrusion upon an occupied dwelling area or hunting ground. They are not life-threatening to either shrimp, but instead warn against some displeasing behavior. When said agonistic intraspecific encounters occur, one shrimp will shoot jets of water toward an intruding shrimp, but will do this within a range that will not allow for formation of a bubble(usually 9 or 10 mm). At this distance the intruding shrimp is neither killed nor stunned, but only warned that the area upon which he has intruded is occupied. (Herberholz and Schmitz, 1998a; Herberholz and Schmitz, 1998b; Herberholz and Schmitz, 1999; Herberholz and Schmitz, 2001; Hughes, 1996b; Hughes, 1996a)
Bigclaw snapping shrimp are omnivores and often feed on a variety of small marine animals including worms, crustaceans, shellfish, and small fish. They also graze on algae, but this has been documented only in laboratory environments. Most of their food is obtained by ambushing their prey and using their snapping claw to create a jet of water that kills or stuns prey. (Beal, 1983; Kaplan, 1999)
Although they have not been established as an essential food source of any organism, bigclaw snapping shrimp are the prey of many larger fish including weakfish (Cynoscion regalis) and red drum (Sciaenops ocellatus). The larger size of these fish renders inert the ability of bigclaw snapping shrimp to stun organisms by firing its modified pincer. (Mullaney Jr., 1994; Overstreet and Heard, 1978)
Bigclaw snapping shrimp are not a main food staple of any organism, and as feeders on small, abundant organisms, the ecosystem impact of bigclaw snapping shrimp is uncertain.
In areas where the predators of bigclaw snapping shrimp occur, the shrimp are known to form mutualistic relationships with other fish, particularly gobies (in particular, Cryptocentrus cryptocentrus). The gobies benefit by living in burrows built by the shrimp, and the shrimp benefit by using their antennae to receive tactile signals from the gobies that communicate the absence of predators.
Two main parasites of the bigclaw snapping shrimp are an isopod Parabopyrella richardsonae and group of parasitic isopods in the Family Entoniscidae (also isopods). Parabopyrella richardsonae attaches between the segments of the shrimp's exoskeleton and steals ingested nutrients from the shrimp. Long-term, this leads to large swollen areas on the soft body of the shrimp that protrude out of the exoskeleton. Entoniscid isopods, particularly Portunion kossmanni and others of the same genus, are internal parasites of bigclaw snapping shrimp. They live in the body cavity of the shrimp where they steal ingested nutrients. In crabs such as Cyclograpsus lavauxi, these isopod parasites occur more often and in higher density in males than in females. Similarly, it is hypothesized that male alpheid shrimp also host more of these parasites than female shrimp. (Beal, 1983; Brockerhoff, 2004; Hutton, 1964; Kaplan, 1999; Karpulus, et al., 1972)
Bigclaw snapping shrimp interact minimally with humans, whether the interactions are active or inadvertent. Bigclaw snapping shrimp can be kept as pets in home aquariums and are exhibited in many public aquariums. There have also been several video studies done, particularly by BBC wildlife's segment "Weird Nature", on bigclaw snapping shrimp and their ability to shoot rapid water jets with their modified pincer. Other similar video studies have been done by Discovery Channel and National Geographic, and have been beneficial to physics and biology researchers, professors, and students. The acquisition and sharing of the information captured in these videos have greatly improved the knowledge of this alpheid's ability. (Kaplan, 1999; Mullaney Jr., 1994; Overstreet and Heard, 1978)
Areas where bigclaw snapping shrimp occur at high densities are sometimes associated with interference with ships' sonar capabilities. The loud "pops" made by the firing of the modified pistol claws of these shrimp living at high densities rival the sounds of sperm Physeter catodon and beluga Delphinapterus leucas whale calls. They have been called the loudest animals in the ocean. (Kaplan, 1999; Knowlton, 1973; Lohse, et al., 2001; Versluis, et al., 2000)
The conservation status of bigclaw snapping shrimp has not been evaluated. Although the abundance and density of bigclaw snapping shrimp have not been extensively studied, there is no known danger to bigclaw snapping shrimp, and populations are regarded as stable. (Herberholz and Schmitz, 1998b; Kaplan, 1999)
Seth Ratliff (author), Radford University, Karen Powers (editor), Radford University.
the body of water between Africa, Europe, the southern ocean (above 60 degrees south latitude), and the western hemisphere. It is the second largest ocean in the world after the Pacific Ocean.
Referring to an animal that lives on or near the bottom of a body of water. Also an aquatic biome consisting of the ocean bottom below the pelagic and coastal zones. Bottom habitats in the very deepest oceans (below 9000 m) are sometimes referred to as the abyssal zone. see also oceanic vent.
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
areas with salty water, usually in coastal marshes and estuaries.
uses smells or other chemicals to communicate
the nearshore aquatic habitats near a coast, or shoreline.
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
an area where a freshwater river meets the ocean and tidal influences result in fluctuations in salinity.
union of egg and spermatozoan
having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.
fertilization takes place within the female's body
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
parental care is carried out by males
marshes are wetland areas often dominated by grasses and reeds.
A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.
Having one mate at a time.
having the capacity to move from one place to another.
the area in which the animal is naturally found, the region in which it is endemic.
active during the night
an animal that mainly eats all kinds of things, including plants and animals
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
the business of buying and selling animals for people to keep in their homes as pets.
structure produced by the calcium carbonate skeletons of coral polyps (Class Anthozoa). Coral reefs are found in warm, shallow oceans with low nutrient availability. They form the basis for rich communities of other invertebrates, plants, fish, and protists. The polyps live only on the reef surface. Because they depend on symbiotic photosynthetic algae, zooxanthellae, they cannot live where light does not penetrate.
mainly lives in oceans, seas, or other bodies of salt water.
remains in the same area
reproduction that includes combining the genetic contribution of two individuals, a male and a female
uses touch to communicate
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
movements of a hard surface that are produced by animals as signals to others
uses sight to communicate
breeding takes place throughout the year
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