Mastigoproctus giganteus

Geographic Range

Giant vinegaroons or giant whip scorpions (Mastigoproctus giganteus) are native to the Nearctic region. They are found in the southwestern United States, including New Mexico, Arizona, Texas, and areas just to the north. They range south into much of Mexico, and are also found in Florida. (Carrel and Britt, 2009; Punzo, 2005; Punzo, 2006)


Giant vinegaroons typically live in arid, desert habitats in the southwest, and scrub forests and grasslands in Florida. They have also been found in dry mountainous areas, as high as about 6,000 m. They can be found taking shelter beneath plant debris, in rock crevices, or in burrows dug by other animals or themselves. (Eisner, et al., 1961; Hembree, 2013; Kern Jr. and Mitchell, 2011; Punzo, 2005; Punzo, 2006)

  • Range elevation
    6000 (high) m
    19685.04 (high) ft

Physical Description

Giant vinegaroons resemble scorpions in many aspects, but are actually more closely related to spiders. Their pedipalps are modified into two large claws, and they have two front legs that are held aloft, and six legs that are used for locomotion. They have a thin, flexible tail extending from the end of their abdomen, giving them the common name 'whip scorpions'. Their body is divided into two parts, the cephalothorax (prosoma) and the abdomen (opithosoma). Both sections are flat and oval-shaped. Their walking legs have 7 segments, and their tarsi have 3 parts, ending in 2 claws. There is one pair of eyes located on the front of their head, while there are 3 more eyes on each side of their head. Mastigoproctus giganteus is one of the largest species of vinegaroons, growing to lengths of 40 to 60 mm, not including the tail. The body is typically black, with some sections or appendages brown or reddish-brown. Males have larger pedipalps and a movable finger on the palps. Nymphs resemble adults, though they lack secondary sexual characteristics, such as spines on the palpal trochanter, and the movable finger on the male pedipalps. Nymphal males and females have identical claws. (Hembree, 2013; Punzo, 2005; Schmerge, et al., 2013; Weygoldt, 1970; Weygoldt, 1971)

  • Range length
    40 to 60 mm
    1.57 to 2.36 in


Mastigoproctus giganteus is hemimetabolous. Once eggs hatch, the nymphs climb aboard the back of the female, and remain there for about a month, until their first molt. After their first molt, the nymphs disperse. Giant vinegaroons have 4 nymphal stages, with 4 molts, before reaching adulthood. Molts occur about once a year, usually during the summer. Preparing to molt can take months, during which, vinegaroons construct a molting chamber they do not leave, not even to feed. The opithosoma visibly inflates, until the skin splits, and the newly molted instar emerges from the skin. The new instar is white, and stays white for 2 or 3 days. Complete pigmentation and sclerotization takes 3 to 4 weeks. After the fourth and final molt, the adult is sexually mature, with secondary sexual characteristics that were not present in the nymphal stages. (Weygoldt, 1970; Weygoldt, 1971)


Mating typically takes place at night, during the fall season for Mastigoproctus giganteus. To initiate mating, the female first cautiously approaches the male. If the female does not want to mate, pairs often get into fights, where they push against each other with their pedipalps, until both back away from each other and rock back and forth. Typically, the male is the first to leave. However, if the female is willing, the male aggressively grabs at the female with his palps, struggling with her, until he is able to grab onto her first pair of legs, the antenniform legs used for sensory purposes. He then grabs the tips of her antenniform legs with his chelicerae. The male walks backwards, dragging the female with him. After several steps, he stops, and moves towards her, stroking her antenniform legs and pedipalps with his pedipalps. In response, the female moves backwards, opening her pedipalps. He moves towards her again, touching her and the surrounding area with his antenniform legs. The female continues to move backwards until the male also begins to move backwards in the other direction, pulling her towards him and beginning the series of motions all over again. This courtship "dance" may continue for several hours, until the male eventually releases the female's antenniform legs with his pedipalps, but not his chelicerae. He turns so they are both facing the same direction, and the female grasps the male's abdomen with her pedipalps. The male moves forward, secreting the spermatophore on the ground as he does so. The spermatophore takes 2 or more hours to form, during which the pair remains motionless. When it is fully formed, the male pulls the female forward towards the spermatophore. The gonopore of the female takes up the sperm carrier from the spermatophore, and the pair releases each other. The male then turns around, and climbs partially over the female so he can use his palpal chelae to manipulate the sperm carriers and her gonopore, pushing the sperm carriers inside her. The male may do this manipulation for two hours or more. Eventually the pair separates. (Kern Jr. and Mitchell, 2011; Weygoldt, 1970)

After mating, females carry the fertilized eggs internally for a few months. They then lay the eggs in a fluid filled sac, with each sac containing 30 to 40 eggs. The eggs are protected from dessication by a moist membrane. The sac is carried by the female, held from her abdomen. Females remain in their burrow during this process for an additional two months, staying motionless and holding her abdomen and the egg sac off the ground while the eggs develop. Finally, the eggs hatch and climb aboard the female's back, remaining there about a month until their first molt. By this time, the female is usually so weak and starved that she falls into a state of lethargy, and eventually dies. Because of this, females only produce one egg sac in their lives. Mastigoproctus giganteus reaches sexual maturity in 3 to 4 years. (Cloudsley-Thompson, 1968; Hembree, 2013; Kern Jr. and Mitchell, 2011)

  • Breeding interval
    Females breed only once during their lives.
  • Breeding season
    Giant vinegaroons mate in the fall.
  • Range number of offspring
    30 to 40
  • Average time to independence
    1 months
  • Range age at sexual or reproductive maturity (female)
    3 to 4 years
  • Range age at sexual or reproductive maturity (male)
    3 to 4 years

Females of Mastigoproctus giganteus exhibit significant parental care. They provide provisioning in the eggs, and carry the eggs internally for several weeks after fertilization. They also carry the eggs in an egg sac held from the abdomen for two months. After the eggs hatch, the young offspring climb onto the back of the female and stay there until the first molt. During this time, the female does not leave her burrow to feed. Her investment in their care and protection is so great that by the time the young disperse, she is so weak and starved that she dies shortly thereafter. (Cloudsley-Thompson, 1968; Kern Jr. and Mitchell, 2011; Punzo, 2005)

  • Parental Investment
  • female parental care
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • protecting
      • female


Mastigoproctus giganteus has an average lifespan of 4 to 7 years, though individuals often live longer. (Hembree, 2013)

  • Typical lifespan
    Status: wild
    4 to 7+ years


Mastigoproctus giganteus is nocturnal, hunting during the night and taking shelter during the daylight, when temperatures are warm. Adults are usually solitary, staying in their burrows or shelters alone. While some take shelter between rocks or under debris, many giant vinegaroons are fossorial and dig their own burrows. They use their large pedipalps to dig, and carry the excavated sediment away to one pile that is used throughout the digging process. Some burrows are temporary, while others are used for several months. They will also do maintenance on the burrow, and often construct tunnels and several chambers, though little activity takes place within the burrow. Usually the tunnels and chambers are only large enough for the vinegaroon to turn around. The mouth of the burrow can also be utilized to catch prey, as prey may fall in if the opening is unsealed. Giant vinegaroons are often more active after rains and at other times may stay motionless for hours. Vinegaroons are said to be able to run very quickly, especially when pursuing prey, and have been described as cursorial. However, they likely spend most of their time moving slowly and cautiously, using their antenniform legs to feel the ground as they walk. If their antenniform legs come into contact with a prey item, their pedipalps can usually grab the prey before it can get away. Giant vinegaroons may act very aggressive towards each other, with fights often ending in severe mutilation or death. Larger females have also been observed cannibalizing smaller females. When threatened, they take a defensive posture, with their abdomen and claws raised, and their flagellum tail stiff and outstretched. (Cloudsley-Thompson, 1968; Eisner, et al., 1961; Hembree, 2013; Punzo, 2005; Punzo, 2006; Weygoldt, 1970)

Home Range

Adults may remain in the same burrow for months, though at other times burrows can be temporary. Their home range is restricted only to how far an individual can walk, though they likely remain in the same general area. (Hembree, 2013)

Communication and Perception

Giant vinegaroons walk on their posterior 3 pairs of legs, and use their first pair of legs as sensory organs. The first pair of legs, often referred to as antenniform legs, are carried off the ground, and have receptors on them to detect chemical and tactile stimuli. They also detect vibrations. They are used to find prey and mates, since they are nocturnal, and their vision is weak. Their eyes can distinguish light and dark, but probably nothing more. They walk along slowly, with their antenniform legs moving along the ground and other substrates. If their antenniform legs come into contact with a prey item, they quickly snatch it with their pedipalps. The antenniform legs can also be used to find water sources, such as moist sand. Their tail and modified pedipalps also act as sensory organs. The pairs of legs used for locomotion are covered in sensory hairs. Tactile connections are used throughout the mating process, as the male holds on to the female using his palps, chelicerae, and antenniform legs. (Cloudsley-Thompson, 1968; Crawford and Cloudsle, 1971; Kern Jr. and Mitchell, 2011; Punzo, 2006; Schmerge, et al., 2013; Weygoldt, 1970)

Food Habits

Mastigoproctus giganteus is a carnivore. It is an efficient predator that feeds on a variety of Arthropods, primarily insects such as cockroaches and crickets, as well as millipedes, and other arachnids. It has even been recorded feeding on small frogs and toads. It uses its large pedipalps to hold prey, while the chelicerae tear and bite the prey. (Carrel and Britt, 2009; Cloudsley-Thompson, 1968; Punzo, 2006; Schmerge, et al., 2013)

  • Animal Foods
  • amphibians
  • insects
  • terrestrial non-insect arthropods


To defend itself, Mastigoproctus giganteus can spray a substance, mainly comprised of acetic acid, from the pygidial gland at the rear of the body, by the base of the tail. This spray is what gives them the common name 'vinegaroons'. The spray is very effective at warding off predators, and it lingers in the air. Giant vinegaroons are also very accurate with their aim, and since they only spray when physically prodded or touched, predators are at a close range when sprayed. Once a predator has been sprayed, it is usually observed darting away, shaking its head and trying to clean itself, obviously in distress. Giant vinegaroons can discharge their spray as many as 19 times in a row before being depleted. Those that are depleted are able to spray again by the next day. Some small mammals, such as grasshopper mice, deer mice, and shrews, can successfully prey on giant vinegaroons, despite the vinegar spray. These small animals are often very aggressive and persistent, attacking the vinegaroons until they are depleted. Camel spiders are also predators. Larger mammals such as raccoons, armadillos, and feral hogs are also likely predators. (Eisner, et al., 1961; Punzo, 2006; Schmerge, et al., 2013)

Ecosystem Roles

Giant vinegaroons are significant predators of many insects and other arthropods. They are also occasionally prey to small mammals such as deer mice and shrews, as well as larger mammals such as raccoons and wild hogs. (Eisner, et al., 1961; Punzo, 2006; Schmerge, et al., 2013)

Economic Importance for Humans: Positive

Giant vinegaroons can be kept as pets, similar to tarantulas. They are typically kept in aquariums or similar habitats, and are fed insects such as crickets. They can be handled with care. (Backwater Reptiles, 2011)

Economic Importance for Humans: Negative

The defensive, acetic acid substance that Mastigoproctus giganteus sprays from the gland by its tail can cause irritation and pain to a handler or collector in the wild, especially if the substance gets into the eyes. There has been at least one instance of the spray causing blistering of the skin. Giant vinegaroons can also pinch with their large pedipalps, if they feel threatened or disturbed. (Eisner, et al., 1961; Kern Jr. and Mitchell, 2011)

Conservation Status

Mastigoproctus giganteus has no special conservation status.

Other Comments

Mastigoproctus giganteus is also locally referred to as "grampus" in some regions. (Cloudsley-Thompson, 1968)


Angela Miner (author), Animal Diversity Web Staff, Leila Siciliano Martina (editor), Animal Diversity Web Staff.



living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map


living in landscapes dominated by human agriculture.

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


uses smells or other chemicals to communicate

desert or dunes

in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.


animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

female parental care

parental care is carried out by females


union of egg and spermatozoan


Referring to a burrowing life-style or behavior, specialized for digging or burrowing.


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.


An animal that eats mainly insects or spiders.

internal fertilization

fertilization takes place within the female's body


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 the capacity to move from one place to another.


This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

native range

the area in which the animal is naturally found, the region in which it is endemic.


active during the night


reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

pet trade

the business of buying and selling animals for people to keep in their homes as pets.


an animal which has a substance capable of killing, injuring, or impairing other animals through its chemical action (for example, the skin of poison dart frogs).

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season


remains in the same area


offspring are all produced in a single group (litter, clutch, etc.), after which the parent usually dies. Semelparous organisms often only live through a single season/year (or other periodic change in conditions) but may live for many seasons. In both cases reproduction occurs as a single investment of energy in offspring, with no future chance for investment in reproduction.


reproduction that includes combining the genetic contribution of two individuals, a male and a female

sexual ornamentation

one of the sexes (usually males) has special physical structures used in courting the other sex or fighting the same sex. For example: antlers, elongated tails, special spurs.


lives alone


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).


Living on the ground.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.


A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.


movements of a hard surface that are produced by animals as signals to others


Backwater Reptiles, 2011. "Whip Scorpions for Sale" (On-line). Backwater Reptiles. Accessed December 21, 2013 at

Carrel, J., E. Britt. 2009. The whip scorpion, Mastigoproctus giganteus (Uropygi: Thelyphonidae), preys on the chemically defended Florida scrub millipede, Floridobolus penneri) (Spirobolida: Floridobolidae). Florida Entomologist, 92/3: 500-502.

Cloudsley-Thompson, J. 1968. Spiders, Scorpions, Centipedes and Mites. Oxford, England: Pergamon Press.

Crawford, C., J. Cloudsle. 1971. Water relations and desiccation-avoiding behavior in vinegaroon Mastigoproctus giganteus (Arachnidae, Uropygi). Entomologia Experimentalis et Applicata, 14/1: 99-106.

Eisner, T., J. Meinwald, A. Monro, R. Ghent. 1961. Defense mechanisms of Arthropods.1. The composition and function of the spray of the whip scorpion, Mastigoproctus giganteus (Lucas) (Arachnida, Pedipalpida). Journal of Insect Physiology, 6/4: 272-298.

Hembree, D. 2013. Neoichnology of the whip scorpion Mastigoproctus giganteus: complex burrows of predatory terrestrial arthropods. PALAIOS, 28/3-4: 141-162.

Kern Jr., W., R. Mitchell. 2011. "Giant Whip Scorpion Mastigoproctus giganteus giganteus (Lucas, 1835) (Arachnida: Thelyphonida (Uropygi): Thelyphonidae)" (On-line). University of Florida. Accessed December 21, 2013 at

Punzo, F. 2005. Neem seed extract containing azadirachtin affects mortality, growth, and immunological function in the whipscorpion Mastigoproctus giganteus (Lucas) (Arachnida, Uropygi). Bulletin of Environmental Contamination and Toxicology, 75/4: 684-690.

Punzo, F. 2006. Types of shelter sites used by the giant whipscorpion Mastigoproctus giganteus (Arachnida, Uropygi) in a habitat characterized by hard adobe soils. Journal of Arachnology, 34/1: 266-268.

Schmerge, J., D. Riese, S. Hasiotis. 2013. Vinegaroon (Arachnida: Thelyphonida: Theylyphonidae) trackway production and morphology: implications for media and moisture control on trackway morphology and a proposal for a novel system of interpreting Arthropod trace fossils. PALAIOS, 28/1-2: 116-128.

Weygoldt, P. 1970. Courtship Behaviour and Sperm Transfer in the Giant Whip Scorpion, Mastigoproctus giganteus (Lucas) (Uropygi, Thelyphonidae). Behaviour, 36: 1-8.

Weygoldt, P. 1971. Life history and reproductive biology of giant whip scorpion, Mastigoproctus giganteus (Uropygi, Thelyphonidae) from Florida. Journal of Zoology, 164/2: 137-147.