There is remarkable diversity in nature, even when it comes to how different species bring up their young. Us humans, for example, care for our children at least until their late teens, if not until much later, while other mammals and even birds feed their young offspring and teach them to hunt before leaving them to their own devices.
That is in stark contrast to reptiles, who lay their eggs (not all reptiles lay eggs, however) in places they consider relatively safe for their young ones to hatch into the world. Beyond that selection, however, reptiles do nothing at all, often leaving the scene even before the eggs hatch, leaving the fledglings to survive entirely on their own from the moment they are born.
Or so we think. And that could simply be because we haven’t studied these creatures enough. A study by Graham Alexander from Wits University, South Africa, found that females from a species of python in southern Africa (Python natalensis) stay in their nest to incubate their eggs, and also care for the babies after they hatch. Such caring for their offspring comes at great cost to the mothers.
Data for the study was collected using infrared cameras lowered into burrows where radio-tracked pythons had laid eggs. Eight female pythons were studied in all, and they were seen caring for their babies for about two weeks after they hatched. The newborns were kept safe and warm at night within their mother’s coils inside the nest chamber.
“This is the first-ever report of maternal care of babies in an egg-laying snake. I was amazed by the complex reproductive biology of this iconic snake,” Alexander said in a statement Wednesday.
Ensuring the safety and well-being of its babies is detrimental to the mother python, who doesn’t eat anything for the entire duration of her breeding cycle — which lasts for over six months — and consequently loses about 40 percent of body mass. Sometimes, in the months following breeding, mother pythons were found to have died (all pythons in the study survived).
While caring for their newborn, female pythons would transmit heat to them by first basking in the sun outside the burrow. To do this effectively, their skin turns dark — almost black — when they are brooding, so as to absorb as much of the sunlight as possible. Alexander called this process of skin darkening “facultative melanism.”
“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. … Perhaps they just became too weakened to catch food,” he explained in the statement.
There were some other unusual finds too. For instance, female pythons that weren’t breeding, pregnant or receptive had body temperatures lower by over 5 degrees Celsius, compared to other adult females who were “in the family way.” Also, tracking male pythons showed some of them followed receptive females around for months.
Alexander’s paper, published in the Journal of Zoology under the title “Reproductive biology and maternal care of neonates in southern African python (Python natalensis),” is based on seven years of research, during which time he tracked a total of 37 pythons in the Dinokeng Game Reserve, near Pretoria, using radio transmitters.