Bio-Socio/Anthropo English
등록일 : 2018-04-11 14:05 | 최종 승인 : 2018-04-11 14:05
Cedric Dent

[리서치페이퍼=Cedric Dent 기자] Pythons have a reputation even in comparison to many other ruthless animals for being cold-blooded killers, pun intended, but it would appear that they, nonetheless, are at least as good at parenting as many humans if not more so. We tend to raise our children well into their teens, perhaps even their twenties, and from there we let them live independently. Most other mammals as well as birds, in contrast, pretty much feed their young and teach them how to forage for food or hunt, and beyond that, it's time for the young to leave the proverbial nest. Reptiles who lay eggs, though, tend to do literally nothing more than find what seems like a secure location to put the nest. Curiously, though, pythons have proven in a recent study to be the anomaly among their kind.

Graham Alexander of Wits University based in South Africa found in his new study that female pythons in the southern part of the African continent personally incubate their eggs and continue to raise their young after they hatch. The study also shows that this is actually a rather self-sacrificial method of parenting on the part of the mother python. The data collected on this relied on infrared cameras that were lowered very meticulously down into python burrows. The pythons whom they observed were observed in part via radio trackers to monitor their movements. The study watched eight separate pythons in total, each of whom was observed raising their young for a total of two weeks after the hatch.

The study reveals that newborn pythons were coiled within their mothers' coils in order to keep them warm at night inside the nest. "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 recounted in a press release held on the subject Wednesday. He observed even the minutia of the mother pythons' behavior, including the unique behavior of morphing their blemished brown skin to a dark black hue, which he believes is done to absorb extra warmth from UV rays.

Alexander found that mother pythons bask in the sun to raise their body temperature to a peak of 104 degrees Fahrenheit because it accelerates their metabolism. With that, they return to their burrows to envelop their eggs to sustain warmth at night. About 40 to 50 hatchlings come out eventually, and the mother pythons continue to do this same thing for them all for a solid two weeks before leaving them, which is thoroughly uncharacteristic of egg-laying reptiles. It begs the question: why do pythons differ this way?

National Geographic's Joshua Rapp Learn speculates that the reason for this distinctive parenting might correlate with pythons overeating. The snakelets are chocked full of undigested egg yolk when they're first born, which makes them too immobile to hunt and forage for themselves. It also makes them easy and desirable prey. Mother pythons, according to Learn, keep their young warm most likely as a means to help the babies digest their own yolk as soon as possible so that they can become necessarily agile for hunting purposes.

Reuters's Ed Stoddard notes that this is parenting method, however, represents an excessive cost and disadvantage for the mother python, though, because they don't hunt during this time and end up losing as much as 40 percent of their body weight. Alexander's press release actually went as far as to say that some such mother pythons starve during this process. It's the reason why they only lay eggs once every two to three years, which is also unique to them in comparison to other egg-laying reptiles who generally lay eggs annually. "There must be an evolutionary advantage," according to Alexander, "because if the mother is foregoing feeding all the time, it's obviously a big cost to her, so there must be some benefit that outweighs that cost."

It's not just the endurance of such a long period without feeding in and of itself, though. Remember: they're constantly accelerating their metabolisms as well due to all the sunlight they soak in to heat themselves to peak temperatures. This also lends credence to Learn's conjecture about pythons overeating because this would explain the further purpose of that behavior. "All of this takes its toll on mother pythons," according to Alexander. He adds that "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 were able to catch in the months after leaving the nest. Some of them never recover."

Alexander also made another bizarre observation about male pythons pursuing receptive female pythons for a somewhat ridiculously long time in courtship. "In one case, one male was recorded following a female for more than two kilometers over a three-month period," he said.

[researchpaper 리서치페이퍼=Cedric Dent 기자]

[리서치페이퍼=Cedric Dent 기자]
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