The Rinkhals Spitting Cobra

Now, how many animals are true spitters?. One can think of a few mammals naturally. And as a former zookeeper, I get a very vivid memory of partly digested, regurgitated grass, accompanied by plenty of saliva, slowly trickling down from my newly washed hair, over my face and from there, in underneath my T-shirt . Now, at that point I was thoroughly convinced that I would never desire keeping any animal that would feel it necessary to take the time out of their busy schedules to expel bodily fluids on my person simply for the fun of it, be it from one end or the other. But as I sit here and look up at my beloved Rinkhals spitting cobra, I realize that although I may be nothing but a food carrying target to my hooded protégé. I am probably the proudest one around J

Now, the first question that arises, is naturally: Why is this "cobra" not in the genus Naja along with most of the other "Cobras"?.

This is yet another good example in the ongoing "battle against the common names", however, if one common name is suiting- the ‘cobra’ given on this one is fairly well deserved.

Our friend is thereby under the same spell as the King cobra.

As many of you will know, the King is placed within the genus Ophiophagus, and with no subspecies, is in the same situation as the Hemachatus.

Both of these genera bear a great resemblance to the True cobras, but also posses some remarkable differences from these, resulting in the placement outside of Naja, (with the close connection pointed out by the common name).

The Rinkhals is as previously mentioned, monotypic. There are however a few different color forms of these. Much like in the case of Naja kaouthia "suphanensis"which is still rightfully considered simply a color form of Naja kaouthia. Or in Naja naja "karachiensis", which is still just another Naja naja sporting a black color rather than the typical brown. These are all, taxonomically speaking, simply considered different color forms with differing distributions - not different subspecies.

Distribution:

Hemachatus is restricted to the eastern regions of South Africa.

From the Southern Cape province , N.E through the Orange Free State, Lesotho, Transkei, Natal, Western Swaziland and parts of Transvaal.   An isolated population is centered around Inyanga on the Zimbabwe / Mozambique border.

Rinkhals inhabit a wide variety of habitats, everything from sea-level to over 2500 m. above sea-level.    It is mainly associated with montane grasslands in regions of high rainfall.

So, what is the difference between our friend Hemachatus and the rest of the group we call cobras? Lets begin on the ‘outside’:

Rinkhals are fairly robust animals of a medium size, rarely reaching lengths of 150 cm, with an average of about 90-110 cm. The head is short and quite pointed, somewhat resembling that of Acantophis ssp., but without being as distinct from the neck, and with fairly large, black eyes.  As far as head scalation goes, we've got the usual 9 scales on the crown, with the rostral scale being fairly large and obtusely pointed.   Laterally, the nasal is in contact with the single preocular.

The curious thing about this animal is it's strongly keeled scalation on the dorsal surface (arranged in 17-19 rows at mid-body). This, along with the typical grayish black dorsal coloration, gives the animal an almost dirty-looking appearance. As the snake turns around and raises a beautiful broad hood, it almost deceivingly appears to be

a completely different animal, with it's glossy ventral scales (116-150), a dark belly, usually with one or two pale/creamish white cross-bands on the neck (the anterior being narrower (1-2 ventrals scales) than the posterior (up to 7). 

The anal-plate is entire, the subcaudals number 33-47. Of these, the first 3 to 4 are frequently single with the remainder being paired.  There are as previously mentioned, a few different color forms of this species. Some specimens resemble the one depicted below, some brownish in color, variegated, spotted or beautifully barred (shown only in specimens from the Cape province to Pondoland & the Inyanga highlands of Zimbabwe). This naturally making an accurate description of color in Rinkhals, difficult at best.

Rinkhals are also unique amongst African elapids in being (ovo)viviparous. Now, this is another distinguishing difference that makes it easy to understand why these are not in Naja, as all "true cobras" are oviparous. The babies are fairly small  (16-17 cm in length), and numerous (20-30 young- exceptionally 63- with as few as 9 in Zimbabwe), these are conspiciously banded, and born around January to March.

As a personal experience I would like to add my own failure at trying to breed the Rinkhals in captivity.

I introduced the female to the male earlier this year, and was not surprised to see the male vigorously pinning the female down and biting her neck.

This (as most of you know) is not an uncommon practice with quite a few species of snakes- however in my females case, it had fatal results.

The animals were left unsupervised after things seemed to have calmed down, and were separated a few hours after the "bite-incident". 24 hours later, the female was found dead within her cage.

I counted around 6 solid bitemarks, which would not really have meant much (as the marks were not by any means "bad"), if it had not been for the fact that the male obviously injected enough venom to kill her. I cannot explain this for the life of me. If anyone has an answer to why the male would behave in such a manner, I would appreciate hearing any input.

Rinkhals are definitely a nocturnal species, but may occasionally be observed basking during the day.   With regards to captive specimens, my animals are usually found sleeping at daytime, but can easily be woken up and will still vigorously eat- regardless of time of day. 

A curious fact about this species is the ability to feign death, much like Heterodon of the New world. This snake, if presented with no possibility to flee, and faced with a "predator" unfazed by it's spitting- will roll over on it's back melodramatically, open it's mouth and let the tongue hang out, all this to discourage whoever may be  hovering over it.  Soon after the assumed predator has walked away, the animal will roll over on it's belly and slide carelessly away..

As far as diet goes, these are toad eaters in the wild. And before we start cursing this fact and swearing that "we will never again have anything to do with snake, lizard or amphibian feeders!!" - I have to point out that with Hemachatus, anything small enough to fit down their throats is fair game. These act in a typical cobra "feeding frenzy" fashion as soon as the prey item is presented, vigorously attacking the already dead prey, enthusiastically chewing away. And as a word of caution, when Hemachatus smells food - watch out!! At this point they are oblivious to the outside world, and with the venom apparatus fully prepared to bite anything moving within sight, we surely do not want any of our digits in the way..

The venom of this species is less viscous (i.e. thinner) than that of other African elapids, naturally, as thinner fluid is naturally easier to spit. However, the venom of Hemachatus is produced in copious amounts- yields average 80-120 mg. (LD50 1.1-1.6 mg/kg) with an estimated lethal dose for humans of 50-60 mg.

Actual bites from Hemachatus are fairly rare, and deaths in modern times are so far unheard of.  Local symptoms of swelling / bruising is reported in about 25% of cases.  General symptoms of drowsiness, nausea, vomiting, violent abdominal pain / cramps and vertigo often occur, as does a mild pyrexial reaction.  Neurotoxic symptoms are however rare and have only included diplopia and dyspnoea. Ophthalmia has been reported,  but has not caused as severe complications as in some of the spitters in the genus Naja (especially N. nigricollis & N. mossambica). 

Luckily, SAIMR has developed a fairly good polyvalent antivenom, also covering this species.

Thank you for taking the time to read this article, and if anyone of the SHHS members have any idea as to "what went wrong" in my breeding efforts with Hemachatus, I can be reached at Vipera4@hotmail.com

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