Idol snake

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Idol snake
Boa constrictor (2) .jpg

Idol snake ( Boa constrictor )

Subordination : Snakes (serpentes)
Superfamily : Boa-like (Booidea)
Family : Boas (Boidae)
Subfamily : Boa snakes (Boinae)
Genre : boa
Type : Idol snake
Scientific name of the  genus
Linnaeus , 1758
Scientific name of the  species
Boa constrictor
Linnaeus, 1758
The ability to change color is clearly visible in this idol snake.

The Boa constrictor ( Boa constrictor ), also King Snake , Königsboa or Abgottboa called, is one of Mexico to southern South America common type of Boas (Boidae). It is the only species in the monotypical genus Boa .


The species Boa constrictor is characterized by the great diversity of the appearance of its subspecies. The average size of adult specimens varies between one ( Boa c. Imperator ) and three ( Boa c. Constrictor ) meters. The males remain on average 30 to 40 cm smaller than the females. The largest idol snake ever recorded was 3.60 meters long and lived in the Guyana Zoological Park of Georgetown in Guyana . The longest safely documented skin measures 445 cm without a head and is in the Munich State Zoological Collection (ZSM 4961/2012). The coloring of the individual subspecies is just as different as the achievable final size. It ranges from white, red, brown to almost black local forms, with Boa c. imperator has the greatest variety of differently colored local populations. Despite this diversity in the basic coloration, all boas have dark-edged saddle spots on their backs, the shape of which, however, again varies depending on the subspecies. Another special feature of the idol snake is its ability to lighten or darken the color depending on the temperature. A specimen that is darkly colored in the shade can quickly appear several shades lighter when exposed to sunlight.

distribution and habitat

The distribution area of ​​the idol snake extends from the west or east coast of Mexico across Central America to Argentina , from sea level up to 1,000 meters above sea level. The various subspecies and local forms inhabit the most varied of habitats. Areas near water bodies with high humidity and dense scrub can be regarded as typical habitats, even if individual populations do occur in semi-deserts.

Way of life

The idol snake is crepuscular and nocturnal. During the day she hides in caves, hollow trees or other shelters and only comes out from there for occasional sunbathing. The juveniles mainly stay in the branches of trees, while adult specimens, with increasing age and weight, almost exclusively inhabit the ground. But there are exceptions here, too, as the St. Lucia boa mostly lives in trees as an adult. Overall, the idol snake shows little urge to move. A full-grown boa equipped with a transmitter in the wild moved only 135 meters in a period of twelve days.


A boa constrictor devouring a small mammal.
A captured boa constrictor snatches an (already dead) rat.

Except for insects and spiders, the idol snake eats all animals that it can manage in terms of size, even small caimans are beaten. Warm prey is preferred over cold prey, however. The idol snake generally uses two different hunting methods: Either it actively follows the scent trails of the prey or waits as a lurking hunter for the favorable moment. When the snake is close enough to its prey using one of these methods, it snaps at lightning speed and then crushes the victim with its muscular body loops. The prey is compressed so much that it comes to a circulatory collapse and not, as previously suspected, death from suffocation. The Latin species name constrictor ('contractor', ' constricting ') refers to the constricting "choking" by the idol snake. Depending on the size of the prey, this process can take up to 16 minutes and is a considerable effort for the snake. In order not to use up unnecessary energy, the snake feels the prey's heartbeat and stops the choking process as soon as the cardiac arrest has occurred.

A special hunting method has also been observed in young boas: They move their tail like a worm and thus actively attract lizards.


Due to a lack of field research, the experience of keeping the terrarium must be used for reproduction. The corresponding activities take place - depending on the subspecies - only in certain months. During these mating seasons, the female secretes sexual attractants, which the males actively follow. If the male then encounters the female, it scratches the female's flanks with his dorsal spurs until the female finally lifts her tail and allows the hemipenis to penetrate . The advertising can drag on for weeks, and there is always a large number of pairings that can last several hours. The idol snake gives birth to living young who are surrounded by a thin skin called the egg membrane or egg shell at birth. An average of 120 to 150 days elapse between ovulation and birth, with the time of weaning the young often being accompanied by rain. During and after the birth process, the female defends her young, and it has also been observed how females helped their young out of the egg shell by nudging them with their snouts or encouraging them to crawl away. After birth, the young snakes are fully developed and search for food independently.


Different, mostly regionally isolated subspecies are distinguished from idol snakes. The following list was made based on the distribution area from north to south and west to east.

Emperor Boa ( Boa c. Imperator )

The emperor boa shows the greatest variety in color, body structure and size within the idol snake. The name of the species is the imperial cross lying on the forehead, which results from a stripe between the eyes and the longitudinal line from the forehead to the muzzle. However, this can also be completely absent in individual individuals. Also typical compared to the Boa c. constrictor higher number of saddle spots. More detailed genetic studies have shown that this is actually an independent species, not just a subspecies. The individual local manifestations of the emperor boa are made on the basis of the country names of their area of ​​distribution.

Mainland forms

  • Sonora : The distribution area extends to the Sonora region in northwestern Mexico. The animals reach an average length of 160 to 200 cm. The basic color is dark gray, the imperator cross is mostly present.
  • Mexico : The distribution area stretches over the south east coast of Mexico down to Guatemala, more precisely from Tamaulipas to the Yucatan Peninsula . The final size that can be achieved is controversial, Stöckl & Stöckl speak of the smallest emperor boa with an average final size of 100 to 140 cm while Bonny reports a specimen that is 270 cm tall. Overall, the physique is very slim, the imperator's cross is rarely present and the basic color consists of light brown tones going into yellow. Many specimens have an orange colored underside. The saddle patch pattern is often laterally joined together.
The assumed distribution area of ​​the emperor boa (
Boa c. Imperator ) in Central America.
  • Honduras : The Kaiserboas known as the Honduras variant come from imports that came to Germany in the mid-1980s. The exact distribution area of ​​this local form is not known, but is likely to extend over the entire Atlantic coast. The average size is 150 to 180 cm. These animals differ from other emperor boas by their rounder and overall slimmer head shape. The emperor's cross is often present. The basic color is a reddish dark brown. In many animals the underside is colored pink to red.
  • El Salvador : El Salvador is home to imperial boas, which have a light to dark gray basic color, but almost black specimens are also known, whose saddle spots are often connected to one another. The emperor's cross is usually present. The average final size is between 150 and 200 cm.
  • Nicaragua : Compared to the local form from El Salvador, the emperor boas in Nicaragua are lighter in color, but also mostly show a connection of the saddle spots. The imperator cross is almost always present. Many emperor boas from Nicaragua also have black speckles all over their bodies. The average size is between 170 and 200 cm.
  • Costa Rica : Two different local forms are known from Costa Rica . The variant from the Pacific coast has a light basic color that ranges from olive green to beige-yellow. The tail spots are often colored red. The distribution of the second variant is suspected on the coast of the Caribbean Sea. These specimens are gray to dark gray, the color of the saddle spots is reddish. The average final size of both variants is 240 to 280 cm.
  • Panama : This variant is one of the least explored imperial boas. The basic color is gray to dark gray with quite thin and widely spaced saddle spots. The final size should be a little over two meters.
  • Colombia : The distribution area extends from southern Panama via Colombia to Venezuela west of the Andes. The exact demarcation to the neighboring Boa c. constrictor is not possible, so that mixed forms are expected, at least in the transition areas. Herpetological studies are lacking here, however. The basic color ranges from light gray to medium brown with reddish colored tail spots, but yellowish or orange specimens have also been spotted. The imperator cross is only partially present and cannot be used as a distinguishing feature to the Boa c. constrictor apply. Overall, the physique is very massive, the final height averages 240 to 300 cm.
  • Ecuador : The exact delimitation of the distribution area within Ecuador is not possible due to a lack of studies. The basic color of these emperor boas is light to dark gray with clearly spaced thin saddle spots. Even the females of this variant rarely grow taller than 200 cm.

Island shapes

  • Sigmaboa (Mexico): The distribution area are the Marias Islands on the Pacific coast of Mexico. The basic color is light yellow to light brown, the saddle spots are often connected with each other. The average final size should be around 200 cm.
  • Crawl Cay (Belize): The range is the Crawl Cay Island in the Caribbean Sea. This variant is characterized by a very muscular build and an elongated head shape. The basic color is light gray to beige brown with very dark saddle spots. Often there are black spots all over the body. The final size ranges from 150 to 180 cm.
  • Cay Caulker (Belize): The range is the Caye Caulker off the coast of Belize. In this variant, the red color is completely absent. The basic tone is a light gray with also gray, partly connected saddle spots. The emperor's cross is often present. The final size ranges from 130 to 150 cm.
  • Hog Island (Honduras): The range is the Pig Islands on the Atlantic coast of Honduras. The basic color of this variant is very light to white, the light gray to light brown saddle spots hardly stand out. In some cases, however, light orange specimens can also occur. The final size is around 200 cm.
  • Islas de la Bahia (Honduras): The main islands of Utila, Roatan and Guanaja of the Islas de la Bahía off the Caribbean coast of Honduras are the distribution area of ​​this dark brown to reddish brown variant. The underside is often colored red, which is what gave these emperor boas the name "Firebellies". The average final size is around 200 cm.
  • Corn Islands (Nicaragua): The distribution area of ​​this island variant are the Corn Islands on the Atlantic coast of Nicaragua. In the absence of sufficient type specimens, no description can be made, but Bonny reports no significant deviations compared to the mainland form. However, these animals should only grow a little over 100 cm.

St. Lucia Boa ( Boa c. Orophias )

The distribution area is the island of St. Lucia off the north coast of South America. The basic color is yellow-white to light gray with beige-brown saddle spots and numerous black spots. The tail spots are dark red in young animals, but black in adults. The cheeks are often light pink in color. The final size is 240 to 280 cm.

Dominicaboa ( Boa c. Nebulosa )

The distribution area is the island of Dominica off the northeast coast of South America. The basic color consists of various shades of brown that darken with age. The drawing hardly stands out from the base color, only the light borders remain shadowy. Special features of the Dominicaboa are their extremely slim body and the narrow, flat head. The average size is 180 to 230 cm.

Sabogaboa ( Boa c. Sabogae )

The distribution area are the pearl islands in the Gulf of Panama. The basic color is very light, from beige to light gray to ocher. The narrow saddle spots are often reduced or completely absent. There are uneven spots or cords on the flanks. The tail spots are outlined in intense red to orange and yellow. The eye color ranges from white to red. The final size is 200 to 220 cm.

Long-tailed boa ( Boa c. Longicauda )

In the absence of field studies, the area of ​​distribution cannot be precisely limited, but its existence in the region around the city of Tumbes in northern Peru is certain . The basic color is yellow to ocher with gray-blue to black, very broad saddle spots. The head is lighter colored, in some specimens even white, with black markings. The average size is 230 to 260 cm.

Orton's boa ( Boa c. Ortonii )

The distribution area is in the northwest of Peru in the province of La Libertad , an exact local demarcation to the surrounding boa subspecies is not possible. The basic color is light gray to light brown with gray flanks and dark brown to black saddle spots. The color of the black-rimmed tail spots is orange to red-brown. The underside is light brown to white. Also remarkable is the broad head shape with clearly contrasting cheeks. The final size is 180 to 250 cm.

King boa ( Boa c. Constrictor )

Typical head drawing of the king boa (
Boa c. Constrictor )

The distribution area extends over the entire north of South America east of the Andes , from Trinidad and Tobago down to the south of Brazil. The basic color is very variable and ranges from cream white to light gray to gray-brown. The brownish saddle spots have white inclusions on the flanks. The tail spots are often bright red. The broad head tapers sharply towards the muzzle, which arches slightly upwards. A clear line runs from the forehead to the muzzle. A subdivision into different local variants cannot be made due to a lack of field studies. The representatives of the king boa belong to the longest idol snakes with an average size of 240 to 300 cm.

Black-bellied Boa ( Boa c. Melanogaster )

The main distribution area is in Ecuador directly on the eastern slopes of the Andes. The basic color is light gray to gray-brown with clearly distinct dark gray to black saddle spots. The main distinguishing feature from the king boa, which also occurs in the area, is the dark gray to black belly side. The final height that can be achieved should be between 240 and 300 cm.

Short-tailed boa ( Boa c. Amarali )

The distribution area extends from Santa Cruz de la Sierra in southeastern Bolivia over southern Brazil down to the Paraguay Valley in northern Paraguay. The basic color is a very light gray. The also gray, narrow saddle spots clearly show the typical widow tip pattern. The ventral side is speckled in black and white. What is striking is the very short, dark color of the tail, which erroneously earned this idol snake the name short-tailed boa. The final size is 200 to 220 cm. The short-tailed boa has the bulkiest body of all boa constrictor subspecies. It looks rather squat.

In the event of a disturbance, the body also inflates, sometimes hissing can also be perceived. It takes a little longer to reach sexual maturity than other subspecies, females need about four to five years and males about three to four years. The growth behavior is much less pronounced than z. B. at B. c. imperator or B. c. constrictor.

The southern boa differs significantly from other idol snakes due to its uniform brown color.

Southern boa ( Boa c. Occidentalis )

The distribution area extends from southeastern Bolivia via Paraguay to Argentina. The basic color of the adult animals is dark brown to black with many white spots. The young, however, are light to medium gray with cream-colored tints. The interconnected dark saddle spots, which are still clearly visible in young animals, can no longer be distinguished from the basic color in adult southern boas. The tail is a single color, dark brown to black. The average size is 220 to 280 cm, but specimens over 300 cm are also possible. The southern boa is the only idol snake listed under Appendix I of the Washington Convention on the Protection of Species and is subject to a general ban on marketing.

Idol snake and man

The Mexicans worshiped the idol snake as messenger or emissary of the gods. Accordingly, the movements were seen as indications for people, the hissing is said to have been a sign of impending misfortune. Indians in the upper Amazon basin believe that giant snakes such as the anaconda and boa constrictor impregnate women in the cassava field to produce a brood. If a woman who has recently given birth dies , it is attributed to such rape. The Incas equated giant snakes like the anaconda and idol snake with Amaro , a mythical double-headed snake feared for its destructive power. The idol snake did not occur in the homeland of the Inca in the highlands of the Andes, but Pachacútec Yupanqui is said to have had giant snakes brought to him as tribute payments by subjugated Indian tribes in the lowlands. The snakes were in a prison in Cusco in a snake pit held. Criminals and prisoners of war were fed to them; those who were still alive in the pit after three days are said to have been released. The characteristic drawing of the idol snake can also be found as a motif on numerous pre-Columbian ceramics. The frequent occurrence of this pattern on artefacts from the Sitio Conte archaeological site in Panama suggests that the idol snake played a special role in the mythology of the Gran Coclé culture.

The first immigrants also recognized the practical use of the idol snake. The field workers from Africa kept the snakes in boxes during the day so that they could live freely in the house at night to fight the rodents. In Europe and North America, on the other hand, the boas were an integral part of the migratory animal huts, where the keepers tried to keep them alive with blankets and hot water bottles. At the same time, components of the idol snake were also ingredients in folk medicine, so that you can still buy “boa oil” on the island of Dominica , which is obtained from boiled idol snakes and is supposed to help against various diseases. Nowadays the idol snakes are represented more as domestic animals than as farm animals in the terrarium keeping, with different effects on the natural occurrence. The light local form of the emperor boa that existed there was exported from the pig islands between 1979 and 1986 in such large numbers for keeping in terrariums that only young animals were found in a field study in 1988. In 1993 the government of Honduras declared the Pig Islands a nature reserve, so that no further exports have taken place since then. On the other hand, humans also contribute to the development of new habitats for the idol snakes. A now stable boa population has formed on the island of Aruba , which has only been proven to have been introduced as an invasive species by humans .


  • Klaus Bonny: The genus Boa - taxonomy and reproduction. Kirschner & Seufer Verlag, 2007, ISBN 3-9808264-5-7 .


  1. K. Bonny (2007): "The Boa genus - taxonomy and reproduction", KUS-Verlag, page 183
  2. H. Stöckl & E. Stöckl (2007): “Purebred Boa Constrictor”, M&S Reptilien Verlag, pages 113 to 115
  3. ^ Frank Glaw & Michael Franzen: On the maximum length of Boa constrictor (Serpentes, Boidae). In: Spixiana. Pfeil-Verlag, 2016, p. 264 , accessed on February 19, 2018 (English).
  4. u. a. K. Bonny (2007): "The Boa genus - taxonomy and reproduction", KUS-Verlag
  5. L. Trutnau (2002): "Non-toxic snakes" Volume 1, Ulmer Verlag, page 159
  6. S. Binder & A. Lamp (2007): "Boa constrictor - Die Abgottschlange", Natur und Tier Verlag, page 58
  7. ^ G. Montgomery & A. Rand (1978): "Movements, body temperature and hunting strategy of a Boa constrictor", Copeia Volume 3, page 532
  8. VC Quesnel & L. Woe child (1969): Observations on the constrictive phase of feeding behavior in Boa constrictor. J. Trinidad Field Nat. Club, pages 12-13
  9. ^ S. Binder & A. Lamp (2007): "Boa constrictor - Die Abgottschlange", Nature and Tier Verlag, pages 59 to 60
  10. Scott M. Boback, Allison E. Hall, Katelyn J. McCann, Amanda W. Hayes, Jeffrey S. Forrester, Charles F. Zwemer: Snake modulates constriction in response to prey's heartbeat. Biology Letters , May 2012. DOI: 10.1098 / rsbl.2011.1105
  11. Scott M. Boback, Allison E. Hall, Katelyn J. McCann, Amanda W. Hayes, Jeffrey S. Forrester, Charles F. Zwemer: Snake modulates constriction in response to prey's heartbeat . In: Biology Letters . 2012, doi : 10.1098 / rsbl.2011.1105 .
  12. CW Radcliffe, D. Chiszar & HB Smith (1980): "Prey-induced caudal movements in Boa constrictor with comments on the evolution of caudal luring", Bulletin of Maryland Herpetological Society No. 16, pages 19 to 22
  13. K. Bonny (2007): "The Boa genus - taxonomy and reproduction", KUS-Verlag, pages 181 to 221
  14. ^ R. Graham Reynolds, Matthew L. Niemiller, Liam J. Revell: Toward a Tree-of-Life for the boas and pythons: Multilocus species-level phylogeny with unprecedented taxon sampling . In: Molecular Phylogenetics and Evolution . tape 71 , February 1, 2014, p. 201–213 , doi : 10.1016 / j.ympev.2013.11.011 ( [accessed October 23, 2016]).
  15. H. Stöckl & E. Stöckl (2007): "Purebred Boa constrictor", M&S Reptilien Verlag, page 22
  16. K. Bonny (2007): "The Boa genus - taxonomy and reproduction", KUS-Verlag, page 31
  17. K. Bonny (2007): "The Boa genus - taxonomy and reproduction", KUS-Verlag, page 56
  18. ^ Brehms Tierleben Volume 4, Paul Franke Verlag, pages 128 to 129
  19. Baladji Mundkur: The Cult of the Serpent, An Interdisciplinary Survey of its Manifestations and Origins. State University of New York Press, Albany 1983. p. 57.
  20. ^ Paul Steele: Handbook of Inca Mythology. ABC-Clio, 2004. p. 96. sv Amaru (Amaro).
  21. ^ Mary W. Helms: The Curassow's Crest: Myths and Symbols in the Ceramics of Ancient Panama. University of Florida Press, Gainesville 2000. pp. 12-13. and passim.
  22. ^ Brehms Tierleben Volume 4, Paul Franke Verlag, page 127
  23. K. Bonny (2007): "The Boa genus - taxonomy and reproduction", KUS-Verlag, pages 147 to 148
  24. L. Wilson & G. Cruz Diaz (1993): "The Herpetofauna of the Cayos Cochinos", Herpetological Nature History Volume 1, pages 13-23
  25. H. Stöckl & E. Stöckl (2007): "Purebred Boa constrictor", M & S Verlag, pages 100 to 102

Web links

Commons : Idol snake Boa constrictor  - Collection of images, videos and audio files
Wiktionary: idol snake  - explanations of meanings, word origins, synonyms, translations