Rinkhals
| Rinkhals | |
|---|---|
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Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Order: | Squamata |
| Suborder: | Serpentes |
| Family: | Elapidae |
| Genus: | Hemachatus Fleming, 1822 |
| Species: | H. haemachatus
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| Binomial name | |
| Hemachatus haemachatus (Bonnaterre, 1790)
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Extant (resident)
Possibly extinct
Presence Uncertain & Origin Uncertain
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| Synonyms | |
The rinkhals (/ˈrɪŋk(h)æls/; Hemachatus haemachatus), also known as the ringhals /ˈrɪŋhæls/[4] or ring-necked spitting cobra,[5] is a species of venomous snake in the family Elapidae. The species is found in parts of southern Africa.[1][3] It is not a true cobra in that it does not belong to the genus Naja, but instead belongs to the monotypic genus Hemachatus. While rinkhals bear a great resemblance to true cobras, they also possess some remarkable differences from these, resulting in their placement outside the genus Naja.[6] In 2023, the Zimbabwe population was described as a new species, H. nyangensis.[7]
Description
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Colouration varies throughout its distribution area, but a characteristic of the species is the belly is dark with one or two light-coloured crossbands on the throat. Their average length is 90–110 cm.[6] Some individuals may have a mostly black body, while others are striped. Rinkhals scales are distinct from those of Naja cobras in that they are ridged and keel-like. Also unlike members of the genus Naja, rinkhals lack solid teeth on their maxilla.[8]
Scale pattern
[edit]- dorsal scales are keeled[10]
- 17–19 rows of dorsal scales at midbody
- 116–150 ventral scales
- anal plate is entire
- 30–47 subcaudal scales, paired
- 7 upper labial scales
- upper labials 3 and 4 entering the eye
- 1 preocular (rarely up to 3)
- 3 postoculars
- 8–9 lower labials
Distribution
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This species is found in the Western and Eastern Cape provinces of South Africa, northeast through the Free State, Lesotho, KwaZulu-Natal, South Africa, Western Eswatini, Mpumalanga and parts of Gauteng, South Africa. An isolated population is centered on Inyanga on the Zimbabwe-Mozambique border.[6] There are no recent records from this population, so scientists assume this population might be extinct.[1]
Habitat
[edit]The rinkhals generally prefers grassland habitats ranging from the coast to altitudes of up to 2500 meters. The rinkhals is extremely common on the Highveld and in the grasslands of KwaZulu-Natal.[10] Since the rinkhals has a natural propensity to eat frogs and toads, they can also commonly be found near wetlands in its range.[11]
Behaviour and diet
[edit]The rinkhals is diurnal, and hunts during the daytime hours. The rinkhals has a varied diet, and will prey upon any vertebrate that is small enough for it to eat.[12] The rinkhals will most commonly eat toads in the wild, but it has also been recorded to consume rodents and other small vertebrates like lizards.[8]
When distressed the rinkhals will spread its hood, showing its distinctive striped neck. As a defense mechanism, the rinkhals will spit venom.[8] They will normally spit from a reared position, lunging and hissing while doing so. The rinkhals has ample control over its venom glands, and can accurately spit venom at ranges up to three meters.[8] Rinkhals are also known to fake death, a behavior seen in other snakes such as the genus Heterodon. Rinkhals engaging in thanatosis will roll over on their backs, open their mouths, and stick their toungues out.[8]
If all other methods of defense fail, the rinkhals will bite to ward off predators. Since they rely on other forms of defense, bites are usually very rare. Bites most often occur when people try to handle the snake.[11]
Reproduction
[edit]Unlike members of the genus Naja, the rinkhals is Ovoviviparous. Instead of laying eggs, the rinkhals gives birth to live young. They give birth to around twenty to thirty live young, but some females can give birth to over sixty live young.[10] Rinkhals usually give birth in the late summer, which in the southern hemisphere corresponds to the months ranging from December to March.[10]
Venom
[edit]The venom of the rinkhals is neurotoxic and partially cytotoxic, and is less viscous than that of other African elapids.[6] When confronting a human, it generally aims its venom at the face. If the venom gets injected, it causes great amount of pain and even necrosis due to the cytotoxic effect. Local symptoms of swelling and bruising is reported in about 25% (a quarter) of cases.[6] General symptoms of drowsiness, nausea, vomiting, violent abdominal pain, cramps and vertigo often occur, as does a mild pyrexial reaction.[6][13] Polyvalent antivenom is effective for the treatment of rinkhals envenomation, and a fatality from a rinkhals bite has not been recorded in over 40 years.[8][11]
If the venom enters the eyes, it causes great pain and inflammation.[13] Corneal damage can occur if left untreated, although timely first aid and eye-washing will usually lead to recovery after a few days.[8]
A polyvalent antivenom exists in South Africa and is manufactured by the South African Vaccine Producers.[8]A polyvalent antivenom is currently being developed by the Universidad de Costa Rica's Instituto Clodomiro Picado.
References
[edit]- ^ a b c Alexander, G.J. (2022). "Hemachatus haemachatus". IUCN Red List of Threatened Species. 2022: e.T177556A197407608. doi:10.2305/IUCN.UK.2022-1.RLTS.T177556A197407608.en. Retrieved 22 August 2022.
- ^ Boulenger, G.A. 1896. Catalogue of the Snakes in the British Museum (Natural History). Volume III., Containing the Colubridæ (Opisthoglyphæ and Proteroglyphæ)... Trustees of the British Museum (Natural History). London. p. 389.
- ^ a b Hemachatus haemachatus at the Reptarium.cz Reptile Database. Accessed 22 August 2022.
- ^ "ringhals". The Chambers Dictionary (9th ed.). Chambers. 2003. ISBN 0-550-10105-5.
- ^ "Ring Necked Spitting Cobra". Encyclopedia of Life. Retrieved 17 August 2022.
- ^ a b c d e f S. Hunter (2000). "Venomous Reptiles".
- ^ Major, Tom; et al. (2023). "Museum DNA reveals a new, potentially extinct species of rinkhals (Serpentes: Elapidae: Hemachatus) from the Eastern Highlands of Zimbabwe". PLOS ONE. 18 (9): e0291432. Bibcode:2023PLoSO..1891432M. doi:10.1371/journal.pone.0291432. PMC 10529548. PMID 37756254.
- ^ a b c d e f g h Kemp, Ashley (2019-07-24). "More info on the Rinkhals". African Snakebite Institute. Retrieved 2025-02-06.
- ^ R. Mastenbroek (2002). "Rinkhals". Archived from the original on 2007-11-24.
- ^ a b c d Branch, Bill. 2004. Field Guide to Snakes and Other Reptiles of Southern Africa, Third Revised edition, Second impression. Ralph Curtis Books. Sanibel Island, Florida. 400 pp. ISBN 0-88359-042-5.
- ^ a b c "Rinkhals - ASI". African Snakebite Institute. Retrieved 2025-02-06.
- ^ "The Rinkhals Spitting Cobra". www.venomousreptiles.org. Retrieved 2025-02-06.
- ^ a b B. Branch (1988). Field Guide to the Snakes and Other Reptiles of southern Africa. Struik, Cape Town.
Further reading
[edit]- Access Professional Development. 2022. Rinkhals (Hemachatus haemachatus). [Online] Available: https://accesspd.co.za/species/Rinkhals (Accessed: 02/02/2022)
External links
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Media related to Hemachatus haemachatus at Wikimedia Commons