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Why female pythons make great moms

New research from the Wits School of Animal Plant and Environmental Sciences has identified a group of female pythons that nurture their offspring to a surprising degree. South African pythons not only incubate their eggs but also care for the babies after they have hatched.

“This is the first-ever report of maternal care of babies in an egg-laying snake,” said study author Graham Alexander.

For his investigation, Professor Alexander conducted intensive fieldwork for seven years at the Dinokeng Game Reserve, just north of Pretoria. He used radio transmitters to track the movement of 37 pythons.

Over the course of the study, eight of the pythons laid eggs. Professor Alexander recorded their breeding behavior using infrared video cameras which were carefully lowered into the nest chambers.

“I was amazed by the complex reproductive biology of this iconic snake,” said Professor Alexander.

He discovered that the female pythons make huge sacrifices to nurture their babies. During the six-month breeding cycle, the mothers do not eat at all, causing them to lose about 40 percent of their body mass.

The female snakes also turn black while breeding, which is an ability that has been adapted by the pythons to heat up faster while basking in the sun.

“Efficient basking is probably crucial for incubation,” explained Professor Alexander. “Unlike some other python species, southern African pythons are unable to warm their eggs by elevating their metabolism. Instead, our pythons bask near to 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 pregnant females observed in the study were at least 5 degrees Celsius warmer than non-reproductive 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.”

According to Professor Alexander, all of the pythons that were monitored during his research survived, but none of them bred the following year. This groundbreaking study sheds light on the fact that there is still so much this is unknown about the reproductive biology of snakes.

“Research is showing that snake reproductive biology is far more complex and sophisticated than we previously thought, and there is a range of behaviours that have been recorded in several species that can be classed as maternal care.”

“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.”

The research is published in the Journal of Zoology.

By Chrissy Sexton, Staff Writer

Image Credit: Graham Alexander/Wits University

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