Pandinus imperator
ORDER
Scorpiones
FAMILY
Scorpionidae
TAXONOMY
Pandinus imperator Koch, 1841.
OTHER COMMON NAMES
None known.
PHYSICAL CHARACTERISTICS
Has large, well-developed pincer-like pedipalps, is uniformly covered with hard cephalic shield or carapace, and has prehensile tail armed with a stinging apparatus; usually attains lengths (including tail) of 5–7 in (12.7–17.8 cm) and weighs about 1.1 oz (35 g), but can reach length of 8 in (20.3 cm) and weight of 2 oz (57 g); pregnant females usually weigh over 1.4 oz (40 g) (considered one of the largest scorpions, but not among the heaviest). As adult, males and females act and look similar; however, males are usually narrower or smaller. Has exoskeleton color of glossy dark blue or black, but some may be dark brown and occasionally even greenish; dark color acts as camouflage. Two pedipalp chela (pedipalps) have reddish brown color, and are very granular in texture. There are numerous, clearly visible sensory hairs on the pedipalps, metasoma (tail), and telson (stinger). Tail is long and made up of six segments, ending in large telson, which contains venom glands. Telson terminates in sharp curve, which serves as stinger, and is reddish brown in adults and yellowish in young. Telson of second instar is white, but soon becomes darker after each molt. Four-sectioned thorax contains pair of legs on each section, specifically on undersurface, making total of eight legs (four pairs). Behind fourth pair of legs are ventral comb-like structures known as pectines; males can be also distinguished from females by their longer pectines.
DISTRIBUTION
Western Africa, primarily in Senegal, Guinea-Bissau, Guinea, Côte d'Ivoire, Sierra Leone, Ghana, Togo, Democratic Republic of Congo, Nigeria, Gabon, and Chad.
HABITAT
Lives in tropical forests, rainforests, and savannas, preferring hot, humid environments. Lives in empty or self-made burrows up to 12 in (30 cm) in length. Often found beneath rocks, logs, tree roots, or vegetation debris.
BEHAVIOR
Sensitive to light, so is primarily nocturnal. It is unusually docile and very slow to sting. Although young use stingers in normal fashion, adults rarely use stinger to subdue prey. They prefer to kill prey with massive claws. Even when stinging in defense, adults may not inject venom. Mothers and young/siblings often live together. Mothers are occasionally cannibalistic, being known to eat a few of their young when necessary. It likes to burrow beneath soil.
FEEDING ECOLOGY AND DIET
Feeds on almost anything that is smaller in size, including arachnids, crickets, insects, small lizards, mealworms, millipedes, and small mice. Young eat pinhead crickets and other small insects. It does not generally pursue prey, but waits for unsuspecting insects and other small animals to pass by. Its eyes, which cannot form sharp images, are of little use in detecting prey. Air and ground vibrations are used primarily in determining the position of prey. When hungry, however, it moves slowly forward supported by its hind legs, with claws open and extended, and tail raised and pointed forward. It quickly strikes with stinger or grasps victim. Larger individuals rarely use stinger to capture prey; instead, they crush it with claws. Smaller and younger ones rely on stinger to subdue prey. They must predigest their food before they consume it. Once prey is subdued, they secrete digestive enzymes onto prey, which liquefies the food and readies it for consumption.
REPRODUCTIVE BIOLOGY
Males spend the majority of time looking for mates. Mating can occur year-round, but warm temperatures are required. When mating, male holds female in grasp, holding and pushing her around until finding suitable place to deposit spermatophore onto a solid substrate. He then pulls female into position over spermatophore, and she accepts it into her genital aperture. Male leaves quickly, to avoid being eaten. It is viviparous (embryos develop within mother, gaining nutrients for growth directly within specialized sacs on female's overiuterus). A highly specialized structure connects embryo's mouth to female's digestive system. Gestation period is 7–9 months. Very tiny young are born alive, with a litter of 9–35. Parental care seems important. Young stay on mother's back, as she protects and cares for them, with increased survival probabilities while in family groups. Young are white at first, but become darker after each molt. They grow and shed entire exoskeleton several times before they are full-grown. They reach sexual maturity at around four years after seven molts. They have a lifespan of about eight years.
CONSERVATION STATUS
Not listed by the IUCN. Because of years of potential over-collection, it has been placed on the CITES Appendix II list (as Threatened) to monitor populations. Primary enemy is humans, who may have one as a pet.
SIGNIFICANCE TO HUMANS
Although large in size, it is not considered dangerous to healthy humans. Its venom is mildly venomous, with a painful sting. It has very strong pedipalps, which can give very painful pinches. Adult males will rarely sting, but young individuals and females with young can be more likely to sting. They are the most common scorpion in captivity, with many exported from western Africa each year.
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