Snake talk by Prof Graham Alexander

graham_alexander

I was privileged to be at a meeting of our herpetological association where professor Graham Alexander was speaking on his research into puff adders and pythons.
His research, undertaken over the last two years in the Kwalata game reserve near Pretoria, South Africa is reaching an end.

Some of the findings coming out of his research are really interesting. He was studying puff adders and pythons, as there have not been any detailed studies done on these species, and they are large snakes that can easily take the transmitters that were being used to track their movements and physiology.

I don’t have the time or the space to do a complete expose on his talk, but will highlight one or two interesting facts that have emerged from his research.
Snakes are top predators, and are less susceptible to fluctuations in prey animal populations like most of the mammalian predators are. This is due to snakes remarkable ability to survive on infrequent meals.
Mammalian predator numbers show a lag in catching up with the number of prey animals when there is a bloom, or an increase in prey population numbers, whereas snakes are ready on the ground to make full use of the additional food supply.
Even though they can survive on infrequent meals, when prey is in abundance they can eat their own body weight in prey every few days, making them and important factor in keeping rodent populations at bay, even when there is an unexpected bloom in rodent numbers. They do not show the same lag in numbers as their mammalian counterparts and having to “catch up” in numbers before being able to make use of the increase in prey numbers.

puff_adder  The Awesome Puff Adder

Puff adders seem to spend the majority of their time above ground, even in winter, when they hide in the leaf litter and humus. Professor Alexander’s explanation for this is that they are at risk underground from the snouted cobra who actively hunts in underground burrows, and will take a puff adder if found underground. He related one such story where the puff adder the researchers were following turned into a snoutie. They wondered why the snakes behaviour and movements had changed, till they tracked the “puffy” and found a snouted cobra instead. The puff adder, transmitter and all was inside the cobra! He kept the snoutie in captivity till it returned his transmitter via regurgitation, then released the cobra back in the area it was captured.

– Puff adders seem to breed most actively between May and June, which is surprising, since these are quite cold months.

– The males are more at risk during the breeding season, as they are actively moving around looking for females, and thus are not making use of their unsurpassed camouflage skills. As much as 50% of the males are lost to predation during this period!

– Puff adders breed often, and produce large litters of babies to balance the amount of snakes that are lost to predation, etc

– Puff adders rely on being invisible, and it has been recorded that they seem to move location after shedding (usually accompanied by defecation), because their location has been compromised by the smell of the shed skin and excrement.

– It seems that a puff adder that is hidden will not bite, even if stood on, in order to maintain it’s cover. Prof Alexander says that when he has found a puffy in this mode, he could not get it to bite, no matter what he did. I seems that the puff adders that are caught out in the open, basking or looking for a mate, are the ones that will bite, as they already feel vulnerable due to them being exposed. (Not a theory I will be testing in a hurry!!)

african_python The Majestic African Rock Python

– Pythons in the study area, on the other hand seemed to have a slower cycle generally. The females only breed once they reach the age of 12 years or so. The males however are sexually active from two years of age. This often results in a large female, 4m in length and weighing about 30-50 kg being courted by a male that is 2m in length and only weighing 3kg (one tenth the size of the female)

– Our African pythons don’t seem to generate heat using muscle vibrations to warm the eggs as their close relatives the Burmese pythons do. The females do however bask in the sun, raising their body temperatures to 40 degrees Celsius and then going underground to warm the eggs. This is amazing, since if their body temperature reaches 43 degrees Celsius, they will die.

– The females do not eat once they have laid their eggs, and will stay with the young for up to 3 weeks after they have hatched. They loose up to 30% of their body weight during this period, mostly due to their heating up and cooling down regimen, which increases their own metabolism and causes the weight loss. Who says there is no maternal care in reptiles!!

– In the test area, no juveniles could be found. The professor said that all the pythons that were found were 2 years or older. It is a mystery where the hatchlings go to mature and grow up, they were nowhere to be found once they had dispersed from the nest. He suspects that the youngsters go arboreal and spend most of their time camouflaged in the trees, catching primarily birds as food, but this aspect of the python’s life cycle requires further research.

– It was previously thought that pythons only go after large prey as the exception rather than the rule, but it was found during the research that this was not the case, with pythons taking about 3 antelope a week in the test area, making them the top predator in that location, as there are no big cats, and showing that the are an important factor in controlling antelope numbers.

This is just a small excerpt of what was a fascinating and educational talk, and shows how little we know about reptiles and the part they play in the ecosystem.
We need more groundbreaking work to be done in this field. My thanks go to Professor Alexander for his dedication to this task and his goal to raise the importance of snakes to both the public in general and scientists, who have previously discounted reptiles as important links in the the eco chain.

Anyone coming on safari with WildFrontier Safaris, wanting to find out more, we will gladly incorporate a herping safari to your itinerary to help you get a better understanding of these magnificent creatures.

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