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Pandinus imperator

By Cheryl Li and Sahil Parikh

Geographic Range

Emperor scorpions, Pandinus imperator, are native to west Africa and are predominantly found in forests of Nigeria, Togo, Sierra Leone, Ghana and the Congo region. (Pandinus, 2009)

Habitat

Emperor scorpions are typically found in hot and humid forests. They reside in burrows and prefer to live under leaf litter, forest debris, stream banks and also in mounds of termites, their main prey. Emperor scorpions tend to live communally and are found in large numbers in regions of human habitation. (Rein, ed. 2009; "Emperor Scorpion (Pandinus imperator)", 2009)

Physical Description

Emperor scorpions are one of the largest species of scorpions in the world, measuring an average of 20 cm in length. They also tend to be heavier than other scorpions, and pregnant females can weigh more than 28 g. The body of the emperor scorpion is shiny black in color with two huge pedipalps (pincers) in the front, four legs and long tail (telson) ending in a stinger. Emperor scorpions have special sensory structures called pectines behind their limbs for sensing features of the terrain. Males usually have larger pectines than females. Like other arthropods, emperor scorpions undergo multiple molts. Their venom is mild and mainly used for defensive purposes; they generally use thier huge claws to kill prey. Like other scorpions, emperor scorpions give off a fluorescent bluish green appearance under UV light. (Rein, ed. 2009; Ross, 2009; "Emperor Scorpion (Pandinus imperator)", 2009)

  • Sexual Dimorphism
  • female larger
  • Range mass
    28 (high) g
    0.99 (high) oz
  • Average length
    20 cm
    7.87 in

Development

Embryonic development of scorpions, including emperor scorpions, occurs in two ways, either apoikogenically or katoikogenically, and these methods differ in the amount of nutrition received from the mother. In apoikogenic development, ova have some yolk. Embryos use the yolk and receive some nourishment from the mother. In katoikogenic development, ova are without yolk, and embryos are nourished through a special feeding apparatus that develops early. Young embryos develop in the female ovariuterus or in specialized diverticula branching from the ovariuterus.

Most scorpions molt multiple times before becoming adults, though juveniles look like adults at all instars. ("Scorpion (Arachnid)", 2001)

Reproduction

Emperor scorpions conduct elaborate mating rituals. Usually, the male grasps the female by pedipalps and engages in a myriad of behaviors including but not limited to sexual stinging and cheliceral "kissing" before depositing the sperm. Like some other arthropods, female emperor scorpions may kill and consume the male after mating has occurred. (Pandinus, 2009; "Emperor Scorpion (Pandinus imperator)", 2009)

Emperor scorpions breed throughout the year. After a gestation period of on average 9 months, females give live birth to 10 to 12 young. Emperor scorpions reach sexual maturity by 4 years of age. ("Oregon Zoo Animals: Emperor Scorpion", 2005; Pandinus, 2009; Rubio, 2008; "Emperor Scorpion (Pandinus imperator)", 2009)

  • Breeding season
    Emperor scorpions breed throughout the year.
  • Range number of offspring
    10 to 12
  • Range gestation period
    9 (low) months
  • Average age at sexual or reproductive maturity (female)
    4 years
  • Average age at sexual or reproductive maturity (male)
    4 years

Emperor scorpions are born defenseless and rely heavily on their mother for food and protection. Newborns are carried on their mother's back until they are old enough to be on their own. Females are generally more aggressive after giving birth. (Mahsberg, 1990; Rubio, 2008)

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

Lifespan/Longevity

Emperor scorpions usually live 5 to 8 years in captivity. Lifespan is likely shorter in the wild. ("Oregon Zoo Animals: Emperor Scorpion", 2005)

  • Range lifespan
    Status: captivity
    5 to 8 years

Behavior

Despite their fierce appearance, emperor scorpions are rather timid by nature (which makes them popular as pets). Emperor scorpions are nocturnal and are rarely active before nightfall. The locomotion of emperor scorpions is unusual in that they use simultaneous extension of the femur-patella joint and the patella-tibia joint for movement. When threatened, they usually flee rather than fight, but if cornered in a small space, they turn aggressive and go into a defensive posture with their stinger ready. Emperor scorpions are social animals and have been observed living in colonies of up to 15 individuals. Cannibalism has been observed in this species, but it is rare. (Mahsberg, 1990; Shultz, 1992)

Home Range

Little information is available regarding the home range of emperor scorpions.

Communication and Perception

The eyesight of emperor scorpions is very poor. Their other senses are well developed, with adaptations like the use of body hairs and pectines to detect the surrounding environment and prey. ("Emperor Scorpion (Pandinus imperator)", 2009)

Food Habits

Emperor scorpions typically eat insects and other arthropods and occasionally hunt down small vertebrates. They commonly eat termites. Adults generally do not kill their prey using their stinger but rather tear apart prey using their powerful pincers. Juveniles, however, depend on their stingers to kill prey. (Casper, 1985; "Emperor Scorpion (Pandinus imperator)", 2009)

  • Primary Diet
  • carnivore
    • eats terrestrial vertebrates
    • eats body fluids
  • Animal Foods
  • mammals
  • body fluids
  • insects
  • terrestrial non-insect arthropods

Predation

Emperor scorpions are eaten by many animals including birds, bats, mammals, and spiders. (Rubio, 2008)

Ecosystem Roles

Emperor scorpions eat a variety of insects and arthropods and are preyed upon by by birds, bats, spiders, and other mammals. (Rubio, 2008)

Economic Importance for Humans: Positive

Emperor scorpions are popular in the pet trade, as they are timid and their venom is mild. Many are imported for the pet trade from Ghana and Togo. They are often used in movies because of their spectacular appearance. The venom of emperor scorpions is also studied, as it is abundant in interesting peptides. A molecule called scorpine has been isolated from the venom of Emperor scorpines. The scorpine molecule seems to have anti-malarial and anti-bacterial qualities. (Gaban, 2002; Montal, 2000; Rubio, 2008)

  • Positive Impacts
  • pet trade
  • research and education

Economic Importance for Humans: Negative

The sting of emperor scorpions is generally mild and not fatal, but a pinch from their pedipalps is known to be painful. (Rubio, 2008)

  • Negative Impacts
  • injures humans

Conservation Status

Emperor scorpions are listed in Appendix II by CITES. Species listed in Appendix II are not threatened, but trade is limited to prevent endangerment by human exploitation. Emperor scorpions are collected for the pet trade and for scientific study. (Rubio, 2008)

Contributors

Cheryl Li (author), Rutgers University, Sahil Parikh (author), Rutgers University, David V. Howe (editor), Rutgers University, Gail McCormick (editor), Animal Diversity Web Staff.

Glossary

Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

World Map

carnivore

an animal that mainly eats meat

ectothermic

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

estuarine

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

fertilization

union of egg and spermatozoan

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

internal fertilization

fertilization takes place within the female's body

keystone species

a species whose presence or absence strongly affects populations of other species in that area such that the extirpation of the keystone species in an area will result in the ultimate extirpation of many more species in that area (Example: sea otter).

monogamous

Having one mate at a time.

motile

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.

nocturnal

active during the night

pet trade

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

sexual

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

social

associates with others of its species; forms social groups.

tactile

uses touch to communicate

terrestrial

Living on the ground.

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

venomous

an animal which has an organ capable of injecting a poisonous substance into a wound (for example, scorpions, jellyfish, and rattlesnakes).

vibrations

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

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

year-round breeding

breeding takes place throughout the year

References

theBIGzoo. 2009. "Emperor Scorpion (Pandinus imperator)" (On-line). theBIGzoo. Accessed November 11, 2009 at www.thebigzoo.com/Animals/Emperor_Scorpion.asp.

Oregon Zoo. 2005. "Oregon Zoo Animals: Emperor Scorpion" (On-line). Accessed November 11, 2009 at http://www.oregonzoo.org/Cards/Insects/emperor.htm.

2001. "Scorpion (Arachnid)" (On-line). Encyclopædia Britannica. Accessed November 11, 2009 at http://www.britannica.com/EBchecked/topic/529352/scorpion/47766/Internal-features.

Casper, G. 1985. Prey capture and stinging behavior in the Emperor Scorpion, Pandinus imperator (Koch) (Scorpiones, Scorpionidae). Journal of Arachnology, 13: 277-283. Accessed November 11, 2009 at http://www.americanarachnology.org/JoA_free/JoA_v13_n3/JoA_v13_p277.pdf.

Gaban, D. 2002. "Emperor Scorpions" (On-line). Accessed November 11, 2009 at http://home.mindspring.com/~drrod1/.

Mahsberg, D. 1990. Brood care and family cohesion in the tropical scorpion Pandinus imperator (Koch) (Scorpiones: Scorpionidae). Acta Zoologica Fennica, 190: 267-272.

Montal, M. 2000. Scorpine, an anti-malaria and anti-bacterial agent purified from scorpion venom. FEBS Letters, 471: 165-168. Accessed November 11, 2009 at http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6T36-400W9P1-B-7&_cdi=4938&_user=526750&_orig=search&_coverDate=04%2F14%2F2000&_sk=995289997&view=c&wchp=dGLbVlb-zSkzV&md5=27cf84b2f34e431c1ac13a4c7aa3a121&ie=/sdarticle.pdf.

Pandinus, I. 2009. "The Story Behind Pandinus Imperator" (On-line). Accessed November 11, 2009 at http://www.pandinusimperator.nl/EN/story_EN.htm.

Rein, J. ed. 2009. "Pandinus imperator" (On-line). The Scorpion Files. Accessed November 11, 2009 at http://www.ntnu.no/ub/scorpion-files/p_imperator.php.

Ross, L. 2009. "Development and Care of Early-Instar Pandinus imperator" (On-line). Accessed November 11, 2009 at www.pandinusimperator.nl/EN/Earlyinstars.htm.

Rubio, M. 2008. Scorpions: Everything about Purchase, Care, Feeding, and Housing. US: Barrons Educational Series Inc. Accessed November 11, 2009 at http://books.google.com/books?id=N05C7CJUscoC&pg=PT32&lpg=PT32&dq=%22Commonly+Available+Scorpions%22&source=bl&ots=s81GHgs5Xa&sig=UwyExpLKOlhBn9rkeKsGExazSZg&hl=en&ei=o90qS9DLE4XP8Qb_y_2UBw&sa=X&oi=book_result&ct=result&resnum=3&ved=0CBQQ6AEwAg#v=onepage&q=%22Commonly%20Available%20Scorpions%22&f=false.

Shultz, J. 1992. Muscle Firing Patterns in two Arachnids using different methods of Propulsive Leg Extension. Journal of Experimental Biology, 162: 313-329. Accessed November 11, 2009 at http://jeb.biologists.org/cgi/content/abstract/162/1/313.

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