Puff adder

{{Short description|Species of highly venomous snake}} {{About|the viper species "common puff adder", native to Africa|the viper genus commonly known as "puff-adders"|Bitis|the harmless snake native to North America, colloquially known as "puff adder"|Heterodon|the Marvel Comics character|Puff Adder (character)}} {{Use dmy dates|date=March 2023}} {{speciesbox | image = Bitis arietans by Danny S. 1.JPG | status = LC | status_system = IUCN3.1 | status_ref = <ref name=IUCN>{{cite iucn |author1=Wagner, P. |author1-link=Philipp Wagner |author2=Wilms, T. |author2-link=species:Thomas M. Wilms |author3=Luiselli, L. |author3-link=Luca Luiselli |author4=Penner, J. |author4-link=species:Johannes Penner |author5=Rödel, M.-O. |author5-link=species:Mark-Oliver Rödel |author6=Els, J. |author6-link=species:Johannes Els |author7=Al Johany, A.M.H. |author7-link=species:Awadh M. Al-Johany |author8=Egan, D.M. |author8-link=species:Damien M. Egan |author9=Beraduccii [sic], J. |author9-link=Joe Beraducci |author10=Howell, K. |author10-link=Kim Monroe Howell |author11=Msuya, C.A. |author11-link=Charles Andekia Msuya |author12=Ngalason, W. |author12-link=Wilirk Ngalason |author13=Turner, A.A. |author13-link=species:Andrew A. Turner |author14=Zassi-Boulou, A.-G. |author14-link=Ange-Ghislain Zassi-Boulou |author15=Kusamba, C. |author15-link=Chifundera Kusamba |author16=Chippaux, J.-P. |author16-link=Jean-Philippe Chippaux |date=2021 |title=''Bitis arietans'' |article-number=e.T197461A2485974 |doi=10.2305/IUCN.UK.2021-3.RLTS.T197461A2485974.en}}</ref> | genus = Bitis | species = arietans | authority = (Merrem, 1820) | range_map = Bitis arietans distribution map.svg | range_map_caption = {{legend|#c10000|border=none| native range<ref name="IUCN"/>}} | synonyms = {{Collapsible list|title=Click to expand |''Cobra lachesis'' Laurenti, 1768 |''Cobra clotho'' Laurenti, 1768 |''Coluber lachesis'' — Gmelin, 1788 |''Coluber clotho'' — Gmelin, 1788 |''Coluber bitin'' Bonnaterre, 1790 |''Coluber intumescens'' Donndorff, 1798 |''Vipera severa'' Latreille ''In'' Sonnini & Latreille, 1801 |''Vipera (Echidna) arietans'' Merrem, 1820 |''Vipera inflata'' Burchell, 1822 |''Echidna arietans'' — Wagler, 1828 |''Vipera brachyura'' Cuvier, 1829 |''Vipera arietans'' — Schlegel, 1837 |''Clotho (Bitis) arietans'' — Gray, 1842 |''Clotho (Bitis) lateristriga'' Gray, 1842 |''Echidna arietans'' — A.M.C. Duméril, Bibron & A.H.A. Duméril, 1854 |''Bitis arietans'' — Günther, 1858 |''Bitis arietans'' — Boulenger, 1896 |''Cobra lachesis'' — Mertens, 1937 |''Bitis lachesis'' — Mertens, 1938 |''Bitis lachesis lachesis'' — de Witte, 1953 |''Bitis arietans arietans'' — Loveridge, 1953 |''Bitis arietans peghullae'' Steward, 1973 |''Bitis arietans'' — Golay et al., 1993 |''Vipera (Clotho) arietans'' — Herprint Int'l, 1994 |''Bitis arietans'' — Spawls & Branch, 1995<ref name="McD99">McDiarmid RW, Campbell JA, Touré TA (1999). ''Snake Species of the World: A Taxonomic and Geographic Reference, Volume 1''. Washington, District of Columbia: Herpetologists' League. 511 pp. {{ISBN|1-893777-00-6}} (series). {{ISBN|1-893777-01-4}} (volume).</ref> }} }}

The '''puff adder''' ('''''Bitis arietans''''') is a highly venomous viper species found in savannahs and grasslands from Morocco and western Arabia throughout Africa except for the Sahara and rainforest regions.<ref name="USN91">{{cite book|author=U.S. Navy|year=1991 |title=Venomous Snakes of the World|location=New York|publisher=U.S. Government / Dover Publications|isbn=0-486-26629-X}} 204 pp.</ref> It is responsible for causing the most snakebite fatalities in Africa owing to various factors, such as its wide distribution, frequent occurrence in highly populated regions, and aggressive disposition.<ref name="Mal03"/><ref name="Spa04">{{cite book|author1=Spawls, S.|author1-link=Stephen Spawls|author2=Howell, K.|author3=Drewes, R.|author3-link=Robert Clifton Drewes|author4=Ashe, J.|author4-link=species:James Ashe|year=2004|title=A Field Guide to the Reptiles of East Africa|publisher=A & C Black Publishers Ltd.|location=London|isbn=0-7136-6817-2}} 543 pp.</ref> Like all other vipers, it is venomous. Two subspecies are currently recognized, including the nominate subspecies described here.<ref name="ITIS">{{ITIS |id=634949 |taxon=''Bitis arietans'' |access-date=24 July 2006}}</ref>

The species is commonly known as the '''puff adder''',<ref name="Mal03">{{cite book|author1=Mallow, D. |author1-link=David Mallow (herpetologist) |author2=Ludwig, D. |author2-link=David Ludwig (herpetologist) |author3=Nilson, G. |author3-link=Göran Nilson |year=2003|title=True Vipers: Natural History and Toxinology of Old World Vipers |publisher=Krieger Publishing Company|location=Malabar, Florida|isbn=0-89464-877-2}} 359 pp.</ref><ref name="SB95">{{cite book|author=Spawls, S.|author2=Branch, B.|author2-link=William Roy Branch|year=1995|title=The Dangerous Snakes of Africa|publisher=Ralph Curtis Books|location=Sanibel Island, Florida|isbn=0-88359-029-8}} 192 pp.</ref> '''African puff adder''',<ref name="Fic82">{{cite book|author=Fichter, George S.|year=1982|title=Venomous Snakes (A First Book)|publisher=Franklin Watts|location=New York|isbn=0-531-04349-5}} 66 pp.</ref><ref name="Kauf69">{{cite book|author=Kauffeld C.|author-link=species:Carl Frederick Kauffeld|year=1969|title=Snakes: The Keeper and the Kept|location=Garden City, New York|publisher=Doubleday & Company, Inc.|isbn=978-0385086523}} 249 pp.</ref> or '''common puff adder'''.<ref name="Mavin">{{cite web|url=https://www.antivenoms.toxinfo.med.tum.de/indication/BITIS_ARIETANS.html |title=''Bitis arietans''|website= Munich AntiVenom INdex|access-date=15 January 2025}}</ref>

==Taxonomy== German naturalist Blasius Merrem described ''Bitis arietans'' in 1820. The specific name ''arietans'' means "striking violently" and is derived from the Latin ''arieto''.<ref>''Chambers Murray Latin-English Dictionary'' (1976)</ref> The type locality given is "''Promontorio bonae spei'' " (Cape of Good Hope), South Africa.<ref name="McD99"/>

===Subspecies=== {|class=wikitable !Subspecies<ref name="ITIS"/> !Taxon author<ref name="ITIS"/> !Common name !Geographic range |- |''B. a. arietans'' |(Merrem, 1820) |African puff adder |style="width:40%"|Throughout Africa from southern Morocco down to the Western Cape of South Africa, across to the south-west Arabian Peninsula<ref name="Mal03"/><ref name="Spa04"/> |- |''B. a. somalica'' |Parker, 1949 |Somali puff adder |Somalia, northern Kenya<ref name="Mal03"/> |- |}

==Description== The puff adder's usual size is about 1.0 m (39.3 in) in total length (body and tail) and very stout. Large specimens of 190 cm (75 in) total length, weighing over 6.0 kg (13.2 lb) and with a girth of 40 cm (16 in) have been reported. Specimens from Saudi Arabia are not as large, usually no more than {{convert|80|cm|in|abbr=on}} in total length. Males are usually larger than females and have relatively longer tails.<ref name="Mal03"/>

thumb|left|''B. arietans'' (adult) The color pattern varies geographically. The head has two well-marked dark bands – one on the crown and the other between the eyes. On the sides of the head, two oblique, dark bands or bars run from the eye to the supralabials. Below, the head is yellowish white with scattered dark blotches. Iris color ranges from gold to silver-gray. Dorsally, the ground color varies from straw yellow, to light brown, to orange or reddish brown. This is overlaid with a pattern of 18–22 backwardly directed, dark brown to black bands that extend down the back and tail. Usually, these bands are roughly chevron-shaped, but may be more U-shaped in some areas. They also form two to six light-and-dark cross-bands on the tail. Some populations are heavily flecked with brown and black, often obscuring other coloration, giving the animal a dusty-brown or blackish appearance. The belly is yellow or white, with a few scattered dark spots. Newborn young have golden head markings with pinkish to reddish ventral plates toward the lateral edges.<ref name="Mal03"/><ref name="SB95"/> One unusual specimen, described by Branch and Farrell (1988), from Summer Pride, East London, in South Africa, was striped. The pattern consisted of a narrow (one scale wide), pale yellowish stripe that ran from the crown of the head to the tip of the tail.<ref name="Mal03"/> Generally, though, these are relatively dull-looking snakes, except for male specimens from highland East Africa and the Western Cape province of South Africa, that usually have a striking yellow-and-black color pattern.<ref name="SB95"/>

Puff adders have a form of olfactory crypsis, which has been shown to make detecting them difficult for trained dogs and meerkats, both scent-based predators. The exact nature of this ability is not known, but is hypothesized to be related to a low metabolic rate, as well as relocation after shedding and defecating.<ref>{{cite journal|last1=Miller|first1=Ashadee Kay|last2=Maritz|first2=Bryan|last3=McKay|first3=Shannon|last4=Glaudas|first4=Xavier|last5=Alexander|first5=Graham J.|author5-link=Graham J. Alexander|title=An ambusher's arsenal: chemical crypsis in the puff adder (''Bitis arietans'')|journal=Proceedings of the Royal Society B: Biological Sciences|volume=282|issue=1821|date=2015|issn=0962-8452|doi=10.1098/rspb.2015.2182|article-number=20152182|pmid=26674950|pmc=4707760|doi-access=free}}</ref>

===Scalation=== {{see also|Snake scale#Nomenclature of scales}} The head has a less than triangular shape with a blunt and rounded snout. Still, the head is much wider than the neck. The rostral scale is small. The circumorbital ring consists of 10–16 scales. Across the top of the head, there are 7–11 interocular scales; three or four scales separate the suboculars and the supralabials. It has 12 to 17 supralabials and 13–17 sublabials. The first three or four sublabials contact the chin shields, of which only one pair exists. Often, two fangs are on each maxilla, and both can be functional.<ref name="Mal03"/><ref name="SB95"/>

Midbody, the snake has 29–41 rows of dorsal scales. These are strongly keeled except for the outermost rows. The ventral scale count is 123–147, the subcaudals number 14–38. Females have no more than 24 subcaudals. The anal scale is single.<ref name="Mal03"/>

==Geographic distribution and habitat== The species ''Bitis arietans'' may be the most common and widespread snake in Africa.<ref name="Mal03"/> It is found in most African regions and on parts of the Arabian Peninsula.

It is found in all habitats except true deserts, rainforests, and (tropical) alpine habitats. It is most often associated with rocky grasslands.<ref name="Meh87">Mehrtens JM (1987). ''Living Snakes of the World in Color''. New York: Sterling Publishers. 480 pp. {{ISBN|0-8069-6460-X}}.</ref> It is not found in rainforest areas, such as along the coast of West Africa and in Central Africa (i.e., central DR Congo); it is also absent from the Mediterranean coastal region of North Africa. On the Arabian Peninsula, it is found as far north as Ta'if.<ref name="SB95"/> It has been reported to be found in the Dhofar region of southern Oman.<ref name="NRDB">{{NRDB species|genus=Bitis|species=arietans|date=2 August|year=2007}}</ref>

==Behaviour== thumb|Squirrel trailing a puff adder while sounding an alarm call to warn others

Normally a sluggish species, the puff adder relies on camouflage for protection. Locomotion is primarily rectilinear, using the broad ventral scales in a caterpillar fashion and aided by its own weight for traction. When agitated, it can resort to a typical serpentine movement of surprising speed.<ref name="Mal03"/><ref name="Meh87"/> Although mainly terrestrial, it is a good swimmer and can also climb with ease; often it is found basking in low bushes. One specimen was found {{cvt|4.6|m|ft}} above the ground in a densely branched tree.<ref name="Mal03"/>

If disturbed, it hisses loudly and continuously, adopting a tightly coiled defensive posture with the forepart of its body held in a taut "S" shape. At the same time, it may attempt to back away from the threat towards cover. It may strike suddenly and fast, to the side as easily as forwards, before returning quickly to the defensive position, ready to strike again. During a strike, the force of the impact is so strong, and the long fangs penetrate so deeply, that prey items are often killed by the physical trauma alone. The fangs apparently can penetrate soft leather.<ref name="Mal03"/><ref name="Meh87"/>

It can strike to a distance of about one-third of its body length, but juveniles can launch their entire bodies forwards in the process. The puff adder rarely grips its victims, but instead releases quickly to return to the striking position.<ref name="Mal03"/>

thumb|thumbtime=0:05|right|320px|Puff adder puffing (Greyton, Western Cape, South Africa)

==Feeding== Mostly nocturnal, the puff adder rarely forages actively, preferring, instead, to ambush prey as it happens by. Its prey includes mammals (rodents [''Aethomys'' sp., ''Arvicanthis'' sp., ''Mastomys'' sp., ''Otomys'' sp., ''Rattus'' sp., ''Rhabdomys pumilio'', and ''Saccostomus campestris''] and even occasionally small deer), birds, amphibians (such as ''Schismaderma carens''), lizards, other snakes, and tortoises.<ref>{{cite web|url=https://animaldiversity.org/accounts/Bitis_arietans/ |title=''Bitis arietans'' {{!}} Puff Adder |website=Animal Diversity Web}}</ref>

==Reproduction== right|thumb|190px|''B. a. arietans'', juvenile (ready to strike) Female puff adders produce a pheromone to attract males, which engage in neck-wrestling combat dances. A female in Malindi was followed by seven males.<ref name="Spa04"/> They give birth to large numbers of offspring; litters over 80 have been reported, while 50–60 are not unusual. Newborns are {{cvt|12.5|–|17.5|cm}} in length.<ref name="Meh87"/> Very large specimens, particularly those from East Africa, give birth to the highest numbers of offspring. A Kenyan female in a Czech zoo gave birth to 156 young, the largest litter for any species of snake.<ref name="Spa04"/><ref name="SB95"/>

==Captivity== The puff adder does well in captivity, but gluttony has been reported, more heavily in juveniles.<ref>Haagner, G. V. (1988). Gluttony causes death in juvenile puff adder bitis arietans. Koedoe, 31(1). https://doi.org/10.4102/koedoe.v31i1.497 </ref> Kauffeld (1969) mentions that specimens can be maintained for years on only one meal per week, but that when offered all they can eat, the result is often death, or at best wholesale regurgitation.<ref name="Kauf69"/> It is a bad-tempered snake, and some specimens never settle down in captivity, always hissing and puffing when approached.<ref name="Spa04"/>

==Venom== The species ''Bitis arietans'' is responsible for more snakebite fatalities than any other African snake, due to a combination of factors, including its wide distribution, common occurrence, large size, potent venom that is produced in large amounts, long fangs, and habit of basking by footpaths and sitting quietly when approached.<ref name="Mal03"/><ref name="Spa04"/><ref name="SB95"/>

The puff adder's venom has cytotoxic effects<ref name="Wid94">{{cite journal|author=Widgerow AD|author2= Ritz M |author3= Song C. |year=1994|title=Load cycling closure of fasciotomies following puff adder bite |journal=European Journal of Plastic Surgery|volume=17|pages= 40–42|doi=10.1007/BF00176504}}</ref> and is one of the most toxic of any vipers based on LD50.<ref name="Mal03"/> The {{LD50}} values in mice vary: 0.4–2.0 mg/kg intravenously, 0.9–3.7 mg/kg peritoneally, and 4.4–7.7 mg/kg subcutaneously (SC).<ref name="Bro73">{{cite book|author=Brown JH|author-link=John Haynes Brown|year=1973|title=Toxicology and Pharmacology of Venoms from Poisonous Snakes|location=Springfield, Illinois |publisher=Charles C. Thomas |isbn=0-398-02808-7}} 184 pp.</ref> Mallow et al. (2003) give an LD50 range of 1.0–7.75 mg/kg SC. Venom yield is typically 150–350 mg, with a maximum of 750 mg.<ref name="Mal03"/> Brown (1973) mentions a venom yield of 180–750 mg.<ref name="Bro73"/> About {{cvt|100|mg}} are thought to be enough to kill a healthy adult human male, with death occurring after 25 hours.

In humans, bites from this species can produce severe local and systemic symptoms. Based on the degree and type of local effect, bites can be divided into two symptomatic categories – those with little or no surface extravasation, and those with hemorrhages evident as ecchymosis, bleeding, and swelling. In both cases, severe pain and tenderness occur, but in the latter, widespread superficial or deep necrosis and compartment syndrome are seen.<ref name="pmid21226389">{{cite journal |author1=Rainer, Peter P.|author2=Kaufmann, Peter|author3=Smolle-Juettner, Freyja M.|author4=Krejs, Guenter J. |title=Case report: Hyperbaric oxygen in the treatment of puff adder (''Bitis arietans'') bite |journal=Undersea & Hyperbaric Medicine |volume=37 |issue=6 |pages=395–398 |year=2010 |pmid=21226389 |url=http://archive.rubicon-foundation.org/9565 |archive-url=https://archive.today/20130415174256/http://archive.rubicon-foundation.org/9565 |url-status=usurped |archive-date=15 April 2013 |access-date=2012-01-08}}</ref> Serious bites cause limbs to become immovably flexed as a result of significant hemorrhage or coagulation in the affected muscles. Residual induration, however, is rare and usually these areas completely resolve.<ref name="Mal03"/>

Other bite symptoms that may occur in humans include edema, which may become extensive, shock, watery blood oozing from the puncture wounds, nausea and vomiting, subcutaneous bruising, blood blisters that may form rapidly, and painful swelling of the regional lymph nodes. Swelling usually decreases after a few days, except for the area immediately around the bite site. Hypotension, together with weakness, dizziness, and periods of semi- or unconsciousness is also reported.<ref name="Mal03"/>

If not treated carefully, necrosis will spread, causing skin, subcutaneous tissue, and muscle to separate from healthy tissue and eventually slough with serous exudate. The slough may be superficial or deep, sometimes down to the bone. Gangrene and secondary infections commonly occur and can result in loss of digits and limbs.<ref name="Mal03"/><ref name="Spa04"/><ref name="SB95"/>

The fatality rate highly depends on the severity of the bites and some other factors. Deaths can be exceptional and probably occur in less than 15% of all untreated cases (usually in 2–4 days from complications following blood volume deficit and disseminated intravascular coagulation), although some reports show that severe envenomations have a 52% mortality rate.<ref name="USN91"/><ref name='Davidson'>{{cite web|url=http://drdavidson.ucsd.edu/Portals/0/snake/Arietans.htm |title=IMMEDIATE FIRST AID for bites by Puff Adder (''Bitis arietans'') |access-date=2011-09-14 |last=Davidson |first=Terence |website=Snakebite Protocols |publisher=University of California, San Diego |archive-url=https://web.archive.org/web/20120402114801/http://drdavidson.ucsd.edu/Portals/0/snake/Arietans.htm |archive-date=2 April 2012 }}</ref> Most fatalities are associated with poor clinical management and neglect.<ref name="Spa04"/><ref name="SB95"/>

==References==  {{Reflist}}

==Further reading== {{refbegin}} *Access Professional Development (2022). Puff Adder (''Bitis arietans''). [Online] Available: https://accesspd.co.za/species/PuffAdder {{Webarchive|url=https://web.archive.org/web/20220202132845/https://accesspd.co.za/species/PuffAdder |date=2 February 2022 }} (Accessed: 02/02/2022) *Boulenger GA (1896). ''Catalogue of the Snakes in the British Museum (Natural History). Volume III., Containing the ... Viperidæ.'' London: Trustees of the British Museum (Natural History). (Taylor and Francis, printers.) xiv + 727 pp. + Plates I–XXV. (''Bitis arietans'', pp. 493–495). *Branch, Bill (2004). ''Field Guide to Snakes and Other Reptiles of Southern Africa''. Third Revised edition, Second impression. Sanibel Island, Florida: Ralph Curtis Books. 399 pp. {{ISBN|0-88359-042-5}}. (''Bitis arietans'', pp. 114–115 + Plates 3, 12.) *Broadley DG, Cock EV (1975). ''Snakes of Rhodesia''. Zimbabwe: Longman Zimbabwe Ltd. 97 pp. *Broadley DG (1990). ''FitzSimons' Snakes of Southern Africa''. Parklands, South Africa: J Ball & AD Donker Publishers. 387 pp. *Merrem B (1820). ''Versuch eines Systems der Amphibien: Tentamen Systematis Amphibiorum.'' Marburg: J.C. Krieger. xv + 191 pp. + 1 plate. ("''V[ipera]. E[chidna]. arietans'' ", new species, p. 152). (in German and Latin). *Pienaar U de V (1978). ''The reptile fauna of Kruger National Park''. National Parks Board of South Africa. 19 pp. *Spawls S, Howell K, Hinkel H, Menegon M (2018). ''A Field Guide to East African Reptiles, Second Edition''. London, Oxford, New York, New Delhi, Sydney: Bloomsbury Wildlife. 624 pp. {{ISBN|978-1-399-40481-5}} (''Bitis arietans'', pp. 576–577). *Sweeney RCH (1961). ''Snakes of Nyasaland''. Zomba, Nyasaland: The Nyasaland Society and Nyasaland Government. 74 pp. *Turner RM (1972). "Snake bite treatment". ''Black Lechwe'' '''10''' (3): 24–33. {{refend}}

==External links== {{Commons category|Bitis arietans}} {{portal|Snakes}} * {{YouTube|cpE8upWeUGc|Video of ''B. g. gabonica'' and ''B. arietans''.}} Accessed 9 December 2006. * {{YouTube|Ndog8JmbM24|Video of two puff adders: ''B. a. arietans'' and ''B. a. somalica''.}}. Accessed 1 March 2007. * [https://web.archive.org/web/20080314192246/http://www.savp.co.za/Venomous/slides/Puff%20Adder%20bite.html Image of ''B. arietans'' bite that resulted in fasciotomy] at [http://www.savp.co.za/ South African Vaccine Producers]. Accessed 26 July 2008. *[https://web.archive.org/web/20160312135709/http://oo.adu.org.za/content.php?id=45 Birds mob Puff Adder ] – paper in ejournal Ornithological Observations

Category:Bitis Category:Snakes of Africa Category:Reptiles of North Africa Category:Reptiles of Ethiopia Category:Reptiles of Uganda Category:Reptiles described in 1820 Category:Taxa named by Blasius Merrem Category:Articles containing video clips Category:Snakes of Arabia