Ghost crabs inhabit tropical and subtropical areas and can be found on both oceanic and more protected estuarine beaches. They are found on the supralittoral zone (the area above the spring high tide line) of sand beaches, from the water line up to the dunes. (Branco, et al., 2010; Fisher and Tevesz, 1979; da Rosa and Borzone, 2008)
- Aquatic Biomes
- Range elevation
- 0 to 3.05 m
- 0.00 to 10.01 ft
- Average elevation
- 2 m
- 6.56 ft
- Sexual Dimorphism
- male larger
- Average length
- 50 mm
- 1.97 in
- Development - Life Cycle
Mating can occur throughout the year. Unlike other crab species, ghost crabs can mate even when the female’s integument is hard, which means that they can mate anytime after sexual maturation. This is an adaptation to terrestrial life. Mating occurs while both the male and the female have a hard shell. Usually mating will occur somewhere in or near the burrow of the male. Often copulatory plugs are found in ghost crabs; the male will release a seminal fluid along with his sperm that will become hard and prevent rival sperm from reaching the female’s ova. (; Burggren, 1988; Rothschild, 2004)
- Mating System
In the Carolinas, ghost crabs spawn from April through July. Females will mature and ovulate in April and again in August. Females reach sexual maturity when their carapace is larger than 25 mm. Males reach sexual maturity when their carapace is larger than 24 mm. This usually occurs when they are about a year old. (Haley, 1969; Haley, 1972; Hobbs, et al., 2008; Portell, et al., 2003; Rothschild, 2004)
- Breeding season
- Mating occurs throughout the year.
- Average age at sexual or reproductive maturity (female)
- 1 years
- Average age at sexual or reproductive maturity (male)
- 1 years
The female will carry the eggs beneath her body, which will be released into the surf. While carrying the eggs, she must keep them wet by frequently entering the water. Some females may turn upside down in the water to ventilate their eggs. (Mitchell, 2007; Rothschild, 2004)
- Parental Investment
- female parental care
The typical lifespan of (Portell, et al., 2003)is about 3 years.
- Range territory size
- 0 to 400 m^2
Ghost crab burrows can be found from the high tide line to 400 m shoreward. (Hobbs, et al., 2008)
Communication and Perception
Ghost crabs communicate using many sounds, including striking the ground with their claws, stridulation (rubbing together) of their legs and making a “bubbling sound”. Males compete in a ritualized matter that avoids the need for physical contact. (Shields, 1998)
- Communication Channels
Ghost crabs are both predators and scavengers, and they feed at night. Their prey can be influenced by the type of beach they live on. Crabs on oceanfront beaches tend to feed on bean clams (Donax spp.) and mole crabs (Emerita talpoida), while crabs on more protected beaches will feed on the eggs and hatchlings of loggerhead turtles (Caretta caretta). (Knott, 2010)
- Primary Diet
- eats non-insect arthropods
- Animal Foods
- terrestrial non-insect arthropods
- Foraging Behavior
- stores or caches food
Ghost crabs have few terrestrial predators. They are largely nocturnal to reduce the risk of being eaten by shorebirds and gulls. When they do leave their burrows during the day, they are able to slightly change their color to match the surrounding sand. Another predator is the raccoon. (Knott, 2010; Mitchell, 2007)
- Anti-predator Adaptations
- Known Predators
- Raccoons, Procyon
- Burrowing Owl, Speotyto cunicularia
- Gulls, multiple genera
The main role of Donax and Emerita talpoida crabs. They are a crucial part of the food chain, playing an important role in the energy transfer from organic detritus and smaller invertebrates to larger predators. (Fisher and Tevesz, 1979)in its ecosystem is the role of top predator in the filter-feeding based food chain. The majority of their food is live prey, although they are also facultative scavengers. Ghost crabs can consume the majority of the production of both
Economic Importance for Humans: Positive
Ghost crabs have been used as indicators for measuring the impacts of human use on beaches. Their population is relatively easy to monitor; the density of ghost crabs on a beach can be estimated by counting the number of burrows in a certain area. Population densities have declined due to habitat modification and heavy, continuous trampling. Because ghost crabs are apex predators of the habitat, monitoring their population can allow humans to assess the impact of human activity on sandy beach ecosystems. (Hobbs, et al., 2008; Schlacher and Lucrazi, 2009)
- Positive Impacts
- research and education
Economic Importance for Humans: Negative
There are no known adverse effects ofon humans.
Currently, ghost crabs are not considered threatened or endangered. One of the main threats to ghost crabs is off-road vehicles (ORVs). The ORVs can crush or bury the crabs and interfere with their reproductive cycle. ORVs can greatly affect ghost crabs at night when they are feeding. Another threat is a decline in their habitat; construction in the upper intertidal zone for residential or commercial use can caused increased mortality and a potential decline in the population. (Hobbs, et al., 2008; Knott, 2010)
While there is no directly negative influence of ghost crabs on humans, (Barton and Roth, 2008)has been shown to have a negative impact on turtle populations. There have been efforts to control ghost crab populations due to their predation on turtle eggs. Studies have found that ghost crabs consume up to 10% of turtle eggs when they prey on a nest, and they have also been known to prey on the hatchlings. Measures to control populations around turtle nesting sites have included destroying burrows and using raccoons that prey on the crabs.
Lisa Izzo (author), Rutgers University, Nikhita Kothari (author), Rutgers University, David V. Howe (editor), Rutgers University, Renee Mulcrone (editor), Special Projects.
- Atlantic Ocean
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.
uses sound to communicate
- bilateral symmetry
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.
an animal that mainly eats meat
flesh of dead animals.
the nearshore aquatic habitats near a coast, or shoreline.
having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.
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.
- female parental care
parental care is carried out by females
Referring to a burrowing life-style or behavior, specialized for digging or burrowing.
the state that some animals enter during winter in which normal physiological processes are significantly reduced, thus lowering the animal's energy requirements. The act or condition of passing winter in a torpid or resting state, typically involving the abandonment of homoiothermy in mammals.
- intertidal or littoral
the area of shoreline influenced mainly by the tides, between the highest and lowest reaches of the tide. An aquatic habitat.
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.
- native range
the area in which the animal is naturally found, the region in which it is endemic.
active during the night
- saltwater or marine
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
- stores or caches food
places a food item in a special place to be eaten later. Also called "hoarding"
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
- year-round breeding
breeding takes place throughout the year
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