What if you were asked, “what is a mammal?,” simple answer, “a warmblooded creature that suckles it’s offspring,” right? You’re not far from right. Mammals are the only creatures that lactate and suckle their offspring; but that’s not really the whole thing. Nature does not take into account what we think is what, but has a weird means of diversifying the world. That’s what we call evolution. Suckling is mostly associated with mammals, but nature gave that right to a certain spider — an invertebrate — to suckle their young, too.
Related media: Spider Moms Spotted Nursing Their Offspring With Milk
‘A Million Ways To Nurse’ By Nature
The checklist for being a mammal is pretty simple: you need to be warmblooded, having hair or fur, and certainly suckling your young. So imagine scientists’ surprise when they discovered that a spider — an invertebrate that is definitely not a mammal — produces milk and nurses it’s young. This spider is not any of the spiders you know of. The hopping spider known as Toxeus magnus doesn’t really resemble a spider — looks quite like an ant — and (you guessed it), doesn’t behave like a spider, either. How weird?
Normally, when a spider hatches and grow a little bit, it’s abandoned by the mother to strive for food. However, T. magnus live together as a happy little family in a nest, often with enough adults around and several baby spiderlings — how cute. This weird habit by this species of spider is what compelled scientists from the Chinese Academy of Sciences and China’s Hubei University: If they live as families, does the mother take care of her young as they mature? Intriguing question.
The Milking Way
In a scientific quest to find out, the scientists observed the spiders’ comings and goings from the nest over several weeks. The strange thing was: for almost three weeks of observation, they didn’t see any of the spiderlings leaving the nest in search of food. And over the course of weeks, the spiderlings grew more than double their size.
After close observations, they witnessed one of nature’s hidden mystery: the mother spider was producing some sort of fluid (milky) for her offspring. During the first week, the mother left droplets of this fluid around the nest for the spiderlings to find, and eventually, started suckling. (The milk came out of her epigastric furrow, a genital structure in her abdomen).
Surprisingly, after the third week of observation, the spiderlings where now developed enough to search for food on their own, but they kept on suckling. Eventually, they stopped after a month and a half later, but kept on living in the nest. (Those darn slacker teenagers).
Non Bloody Suckling Creatures
T. magnus isn’t the only non-mammal creature to suckle their offspring. Cockroaches do it too, the so called “milky fluid” is deposited into the feed of the embryos, but its not produced on a long-term basis for the nursing of their young into adulthood. The tsetse fly is another pesky creature that has the suckling right, too; giving birth to their offspring and feeding them with a milky fluid, but this fluid is only given for the development of the larvae. Even pigeons also make a sort of “milk,” which both parents produce in specialized glands in their throats while they incubate their eggs.
By now, you might be wondering, what about aqua vertebrates — whales and dolphins? Short story: they suckle. They take relatively short dives underneath their mothers to suckle. In a way, nursing underwater is therefore similar to nursing above water: to be more hydrodynamic, the baby stimulates the mammary glands to eject the milk — since the mother’s nipples are inverted, unless the baby nudge where they are, then starts to point out. The mother then starts to shoot out milk. Whales don’t have lips, so they can’t really suckle the milk, so most of it spill into the ocean.
But it seems this hopping or jumping (or whatever) spider, is the only invertebrate known with this amazing feature of mammals — producing milk and suckling it’s offspring, according to the scientists. They added that, there is the urgent need to reevaluate how frequent this tendency is among other species, both invertebrate and others species. At long last, science has really proven to be way more complex than how we imagined the world.
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Written by: Nana Kwadwo, Wed, Jan 16, 2019.