Breeding King Cobras part 1 – feeding and sexing (Including a new Discovery in hemipene transformation)

I know many visitors to the web site have been waiting patiently for information on this subject. Starting now with feeding and sexing is seasonally correct as now is the right time. If you’re considering breeding King Cobras, you should be aware of the sexes and feeding your snakes the correct amount of food to ensure they’re in good shape for breeding.
Sexing King Cobras is not as straight forward as it is for most species of snake. Adult King Cobras can be sexed buy looking at their size, build, head shape, and the way they spread their hood. However this can cause problems and lead to incorrectly sexed snakes.
To start with size, adult male King Cobras are generally around 12 foot or over depending on a number of factors including race and age. When a male King Cobra reaches sexually maturity its build changes. It becomes far stockier with a larger head and spreads a hood that is wider at the top and as it tapers in, carries on further down the snake when it stands tall.
The smallest King Cobra I’ve had go through this change was an Indonesian (Java) male about 11 foot long. All my other breeding males are 12 foot (as that male is now) or over. I have one male that I’m sure is around 14 foot (I’ll measure him soon and put the results in the diaries). I know of other 14 footers in captivity at the moment and have heard that George Van Horn in the USA has a 17 footer? The largest King Cobra ever recorded was the 18’8″ male I’ve mentioned before at London zoo in the late 1930s.
Breeding females are generally 7 to 9 feet. The smallest I’ve known of is a 5 footer that was guarding a nest of 7 eggs in India. I have a female from Malaysia that’s 10 feet. The maximum size for a female King Cobra is usually 11 foot although there was a breeding female at the New York Zoological Park in 1954 that was 13’4″ long. This however was way back when 18 foot males still existed in the wild! I recently read an article on breeding the King Cobra that stated the male was 9 foot and the female 12 foot. This article also stated that female King Cobras commonly reach 16 feet so I’m afraid I have to dismiss it. In general a breeding male King will be 12 to 14 feet and females 7 to 9 feet. The opposite of the Asian Naja complex were females are much larger than males.
The way to sex King Cobras visually is that males are bigger than females both in length and body weight. In some parts of their range Males and Females are different colours. Males have bigger heads, longer and thicker tails, and as I’ve mentioned a hood that starts closer to the head, spreads wider at the top and gradually tapers down further than on females whose hood is more oval in shape.
When I imported my first pair of King Cobras from Thailand back in the 80’s the exporter told me of this and used it as the sole method to sex King Cobras and indeed the pair of Kings I purchased from him did show these traits.

my old male King Cobra showing typical hood

My old female King Cobra

This isn’t always evident as King Cobras do Hood in different ways to show different expressions and moods. Also the hood shape looks different from various angles. The best example I have of a King expressing different moods with the shape of his hood is also another example of how intelligent these Cobras are. One of my large male Malaysian Kings ‘Nameless’ was let out of his cage and guided to a part of the snake room that was secured to leave a King there temporarily. He had just shed and made such a mess of his cage it needed a thorough cleaning out. After finishing his cadge I thought I’d take a photo of him in his beautiful new skin. To persuade him to hood for the camera, I got his attention with my foot in snake boots. I always wear ‘snake proof’ proven boots when in my King Cobra rooms. I use my feet all the time to aid in my snake handling and on a trip to the US many years ago I was visiting Bill Love when he revived a call informing him his friend was dead after a bite from an Asian cobra to the big toe. He’d been removing retained eggs when he lost his grip, had to drop the snake and if he’d been wearing boots instead of sandals, Bill wouldn’t have received that call!
Just after I took the first photograph, ‘Nameless’ grabbed my foot and tried to envenomate it and venom dripped down the boot. He was obviously in no mood to be messed about and the photo shows it. Moments after the bite, I took a second picture. I’m sure by both the hood shape and the expression on his face he’d thought about what he had done. I’m convinced if nothing else, the long term Kings know that I’m the provider of their food. And I’m sure many of you who have dogs will agree the expression he was showing was “I’m sorry I shouldn’t have done that”!

'Nameless' before the bite

'Nameless' after the bite

It’s well known that King Cobras show facial expressions (and to my knowledge are the only snakes that do), but most observations are limited to a King lowering one side of its jaw to show you a single fang as if to say “I could use this if I wanted to and you’d be sorry”. Not angry enough as to open their mouths and show you both fangs which could mean a bite is on the way!

Male King Cobra showing his 'Elvis lip'

Female King Cobra showing a single fang. Looking superior as if you’re not worthy of both fangs!

The other way to sex King Cobras is by probing them but again this is not as simple with Kings as it is with many other species of snake. Probing is where a blunt lubricated rod is inserted into a Cobras cloaca pointing towards the tail and to one side of the vent.

Probing a male King Cobra

In a male King Cobra, the probe travels a further distance as it enters one of the two inverted penis (known as hemipines although this is not an accurate description as there are two individual penises, not each one being half of the whole structure). In a female King Cobra the probe enters a much shorter distance as it is only slipping into the scent gland. The usual way to measure the distance travelled is to count the number of ventral scales the probe passes. This is done by holding the tip of your thumb at the point where the probe finishes entering the King’s body and then withdrawing the probe, holding the point your thumb is against at the cloaca and counting the number of ventral scales to the tip of the probe.
Many Cobras are sold as female when they are actually males. This has happened to me on occasions and sometimes an experienced snake keeper has shown me a ‘female’ K that I’ve then gone on to prove to be a male. When I first started keeping Cobras in the 80’s, they were all exported from Thailand and by far the greatest numbers of these were males. Some shipments arrived with the bags marked male and female but all later turned out to be males. Then in the 90’s Thailand outlawed the export of its snakes. The Thai government should be congratulated for that, although I would rather see a global situation were no snakes are exported by the 100s. There are ample numbers of snakes being captive bred for the pet trade. I’d rather that instead of a country having a total ban (be it KCs or other snake species), permits are allowed for small shipments of say 10 snakes or less for either scientific reasons or as breeding stock. This way local snake catchers/dealers could still make a living as they could charge much higher prices for these small shipments, and the condition of snakes exported would be far better as the high value would make exporters look after their chargers and the small numbers would elevate the problems caused by overcrowding. Also the fact that these snake species were available, if you went to the trouble of applying for a scientific or breeder permit would prevent the ‘smuggling’ that is sometimes a cause of suffering to the snakes. Around the same time Thailand closed its doors to the trade in wild snakes, Indonesia opened its doors up and I was horrified at the numbers and condition of imported King Cobras that I saw at American dealers back then. The King Cobras exported from Indonesia are often of a more even sex ratio. Cobras now exported from Malaysia are always very male heavy.
There’s a good reason why Cobras are often miss sexed. I have never read or been told about this so it could be a new Discovery! When I probe a litter of my newly hatched Cobras, all the males probed 7 ventral scales and the females just one scale. They continue to probe like this until they reach sexual maturity. Then when the males go through the changes in build that I described earlier (or shortly before), they will probe up to 24 ventral scales and the adult females will probe 2 or 3. Also the probe will move and won’t feel so stiff in the wider scent gland of the mature female.

Measuring the distance probed by counting the scales

Much longer probing of sexually mature King Cobra

Commercially available probes can vary in quality from excellent to out-right dangerous. To probe those 20 plus ventral scales of a sexually mature male I use a blunt knitting needle.

Comparing the good and bad probes

These sexing errors could occur when someone has two or more males of different sizes. An 11 foot male is probed with the largest ‘python probe’ in the owners set and it seems to literally disappear inside the snake and enters the maximum of its length. The King is large bodied has a big head and a long tapering hood. It’s correctly sexed as a male. Then a 7 foot King is looked at, it is less stocky, its hood is more oval and its heads smaller. Then when it’s probed the probe comes to an abrupt halt having only entered into the snake a small distance compared to the 11 footer. The owner possibly didn’t count exactly how many ventral scales it’s passed (and its probably 7). The Cobra is then miss identified as a female.
If the Cobra is well looked after and feeds well in a year or two it will be 11 or 12 feet long and probe well past 7 ventral scales and possibly as many as 22!