Pythons might not be everyone’s idea of cuddly‚ but that’s exactly what they are with their babies‚ a Wits University snake expert has found.
Graham Alexander says female southern African pythons care for their babies for about two weeks after their eggs have hatched. During this time‚ the babies spend nights protected and warmed in their mother’s coils.
“This is the first-ever report of maternal care of babies in an egg-laying snake‚” said Alexander‚ whose findings are based on seven years of intensive fieldwork at the Dinokeng Game Reserve‚ just north of Pretoria.
During his study‚ reported in the Journal of Zoology (London). eight of the 37 radio-tracked pythons laid eggs in aardvark burrows. Alexander recorded their breeding behaviour using infrared video cameras lowered into the nest chambers.
“I was amazed by the complex reproductive biology of this iconic snake‚” said Alexander.
Females do not eat during the six-month breeding cycle and lose about 40% of their mass over this time. They also turn black‚ probably to increase rates of heating while basking in the sunlight.
“Efficient basking is probably crucial for incubation‚” said Alexander. “Unlike some other python species‚ southern African pythons are unable to warm their eggs by elevating their metabolism.
“Instead‚ our pythons bask near the burrow entrance until their body temperature is almost 40°C [within a few degrees of lethal temperatures]‚ and they then coil around the eggs to warm them with their sun-derived body heat.”
The body temperatures of receptive‚ pregnant and brooding females in the study were more than 5°C warmer than non-reproductive females. Even the body temperatures of baby-attending mothers were significantly higher than non-breeding females.
“All of this takes its toll on mother pythons: they take a long time to recover after breeding and so can only produce a clutch every second or third year‚ depending on how many meals they are able to catch in the months after leaving the nest. Some of them never recover‚” said Alexander.
The study also found that male pythons follow receptive females around for months. “In one case‚ one male was recorded following a female for more than 2km over a three-month period‚” said Alexander.
His findings suggest we still have lots to learn about the reproductive biology of snakes. “There is a range of behaviours that have been recorded in several species that can be classed as maternal care‚” he said.
“For example‚ biologists are discovering that females of many types of rattlesnakes show maternal care of babies. In some species‚ mothers appear to even cooperate by taking shifts to look after young. But all these species are live bearing – our python is the first egg-laying species that has been shown to care for its babies.”