Biologist Thor Hanson is back to answer even more of the internet's burning questions about biology. What even are murder hornets? Do female mammals get monthly periods? Is it possible to bring back extinct species? Is coral really an animal? Thor answers all these questions and much more!
THOR HANSON: @Ostone asks, bro, how is coral an animal? What's Hits J? Oh, hitting a joint. So do you want me to say that? I'm biologist and author Thor Hanson. Today, I'll be answering your questions from Twitter. This is "Biology Support Part Two."
@PaulRizzo28 asks, hashtag WildEarth. Do ostriches really hide their head in the sand? No, they don't. It's a myth. And no one's quite sure where that myth came from.
Although there are certain displays that male ostriches do during the breeding season, where they get down on the ground, and move their heads back and forth, and sway, and show off their amazing plumage-- but at no point do they actually bury their head in the sand.
@icedancerBen asks, how do ticks latch on like that? Well, if you ever get a chance to look closely at the mouth of a tick, you will be horrified. They have two little knife-like blades that cut into the flesh, and then something that looks like a tongue but with all of these barbs on it so that when it's inserted, it cannot be pulled out easily again. And that's just the beginning.
The saliva of ticks includes an anticoagulant that prevents your blood from clotting. It includes something to make your blood vessels expand so that more blood comes to the wound. And it includes an analgesic, a painkiller, so that you won't feel a thing.
In fact, the ability of ticks through their bite and their saliva to overcome our defenses is one of the reasons that so many diseases, like Lymes disease, take advantage of ticks. They are freeloaders relying on the ways that ticks overcome our defenses, giving those disease organisms a free entry point into our bodies.
@AmandaSmithSays, weird biology question-- do female mammals get a monthly period or do they just get their periods during the mating season? The answer is that most female mammals don't get a period at all. Menstruation, as we know it in Homo Sapiens, is actually very rare in mammals, known just from our species and mostly a few other primates.
And they have a cycle that is called estrus, which can occur every few days in something like a mouse, or only a few times a year in many of the larger mammals. They reabsorb the uterine lining rather than shedding it.
@FTBLKWoman asks, does salt really hurt slugs? Or is that some cartoon shit? The answer is it really does hurt the slugs. If you've ever left a salt shaker out in a humid environment, you might have noticed that the salt tends to cake up. That's because salt is very good at absorbing moisture.
And a slug is, more or less, like a bag of moisture. So when you salt a slug, the salt dehydrates the slug. It draws the water out of the skin, decicates the slug, and kills it
@HarryHoover asks, how do murder hornets work? Do you just give them a list? So murder hornets have been in the headlines lately because they are recently arrived in North America. They are an Asian species-- the Asian Giant Hornet. And it's believed that they jumped over the Pacific Ocean, not on their own wings, but in shipping containers, arriving probably in the Port of Vancouver in British Columbia and over the border into the state of Washington.
Well, I happen to have murder hornets right here in all three phases of their life cycle-- the larva, the pupa, and the adult. And we focus most of our attention on the adult, because they're large, and scary, and have a potent sting. But, in a lot of ways, the trouble starts right here with the larva.
Because if you can imagine a nest, a colony of murder hornets with hundreds or even thousands of these giant grubs that are hungry all the time, it's quite a job for the adults. And they have developed, then, a particular strategy that sets them apart. They target other social insects, like honeybees or paper wasps, where, if they can succeed in overcoming the colony, they can find a huge amount of food in one place to take back to feed to the kids back home.
And that strategy has led them to evolve this large body size with extremely thick exoskeletons that can withstand the stingers of the insects that they're attacking. So it really is the responsibility of the adults to feed the young that has driven their evolution to be so large and scary in the first place.
@Jake_Vig asks, what's the weirdest animal, platypus excluded? In biology, we don't necessarily think about animals as weird, but we are very interested in the marvelous adaptations that some animals come up with. So when we're talking about finding strange ones, we look in extreme places.
My favorite of these weird environments and odd creatures has to do with the carcasses of whales, what we call whale falls-- when they sink to the bottom of the ocean and create their own little ecosystem. And there are zombie worms that have evolved specifically to devour the bones of whales. But they do so without mouths.
They excrete an acid that dissolves the bones of the whales, and they live alongside bacteria that help transfer the nutrition from those dissolved bones inside the worm itself. So in biology, if you want to find strange creatures, look in strange places.
@Ostoned asks, bro, how is coral an animal? Hits j. So a coral is an animal, a tiny animal, with a mouth and with little tentacles that reach out and grab food from the water-- not altogether dissimilar from something like a barnacle. But where a barnacle lives alone, corals live in colonies of thousands of clone-like individuals. And they take on elaborate shapes to get themselves up off the ocean floor into the water column to feed, but also to allow the dinoflagellates or algae that live alongside them to photosynthesize.
Because the little coral polyps get some nutrition from the photosynthesis going on in their symbiotic algae. And that's why many corals take on shapes that resemble plants. They're trying to increase the surface area of their structures so that more photosynthesis can take place. And we all have a connection, a surprising connection, to corals and other shell-making creatures in everyday life.
That's because when their shells break down in the ocean, particularly in shallow tropical seas where corals and shell-makers are very, very common, those sediments harden into limestone, which we then later mine to produce cement. And you can track the course of the shell into the cement by looking for something called calcium carbonate, which is the main component of shells and is found in cement as well.
And you can do so with the addition of hydrochloric acid, which dissolves that calcium carbonate, producing bubbles of carbon dioxide alongside water. You can see it in the shell and you can see it in the cement. Which means, of course, that, surprisingly enough, even in our most built environments, we're never really that far from a tropical beach.
@Kingkaiju8 asks, hashtag Botany, hashtag Biology-- question for all you plant-centric scientists, are there any plants with pleasant common names but are instead deadly and/or toxic? The answer is, yes. And I happen to have the seeds of one of them right here.
These come from a plant, pleasantly enough, called the Rosary Pea. And it is in the pea family, and they do use these beautiful black and red seeds to make rosaries and other forms of jewelry. But the plant is deadly, deadly toxic. One seed well chewed is enough to kill a person.
@FaunaGrace asks, do bulls really hate the color red? The answer is, no, they don't hate the color red. They can't even see the color red. You could irritate a bull with a polka dot cape or a brown cape just as easily. It's the motion that attracts their attention.
The color red was chosen, one, because it's showy and it may please the audience. And two, for a more grisly purpose, it hides the blood stains that the injured bull might leave as it passes underneath.
@JPetru97 asks, for viruses, the goal is to continue to spread and manufacture by utilizing a host. What good is a dead host? Therefore, is there any reason to believe COVID would mutate to be more deadly, as opposed to more transmissible but less deadly?
Well, the short answer is, yes, we expect that a virus over its history in a population will eventually mutate into something less deadly and very transmissible, because that is in the best interest of the virus itself. But, of course, mutations are random events. So there is still the chance that COVID or other viruses, particularly when they are new in a population, to have a mutation that produces something more severe.
@hobvicore asks, are the cells of an elephant bigger than the cells of a rat? Explain why or why not. Well, the answer is, no. There are limits to how big a cell can grow, whether it's in a rat or an elephant, because cells, like any living thing, they need fuel and they produce waste.
And the way that they get those things into and out of the cell is through a process called diffusion. So if you get too large of a cell, it becomes inefficient. And you can't get the stuff all the way into the middle of the cell where it is required.
Interestingly enough, one of the only creatures out there to get around that limitation of diffusion is a particular group of very small organisms, certain bacteria that have developed bubbles, if you will, within the cell called vacuoles that push all of the essential parts of the cell closer to that cell wall, allowing the cell to grow larger and still be serviced by the process of diffusion from the outside. So are the cells of an elephant larger than the cells of a rat? The answer is, no.
@Islandfangirl1 asks, why will a mother bird abandon its chick if touched by a human? Well, the answer is, they don't. That's a common myth. Many studies that use tagging of young birds rely on going to the nest, applying a small tag to the bird, and then, of course, returning to the nest and allowing the mother to raise that bird to maturity.
Now, that's not to say we should all go out and start touching baby birds, but it does point out that most birds have a very high loyalty to their eggs and to their chicks while they're raising them. And even if those nests are disturbed by us, or by a potential predator, or what have you, the adult birds will most likely return and finish the job.
@Alamedamark asks, question for biologists-- is there any other species that attacks its own species as frequently as humans do? The answer is, yes. There are all sorts of species that attack members of their own species in nature. Consider the praying mantis, where the female will happily decapitate the male after copulation and eat the male to provide a free meal and more energy for raising up her brood of eggs.
Or consider ling cods and various fishes that are perfectly happy to eat smaller individuals of their own species. They choose their meals by size, not by whether or not they're related. But if we want to look for examples of planned attacks in nature it helps to look at one of our closest relatives, the chimpanzees, who are known to organize raids from one neighboring band to another neighboring band with the express purpose of finding isolated individuals, and attacking them, and even killing them. That is a grisly behavior, but one that we can look upon with some familiarity because we see it in our own species.
@ElmosTwitter asks, question for biologists-- is it possible to bring back extinct species? If so, how? Hashtag Biology. Extinction really is, for the most part, forever. That said, there are efforts underway to bring back certain species that have DNA preserved in a frozen state-- for example, woolly mammoths, where there is at least some recognizable DNA in the carcasses that are still available in the frozen tundras of the far North.
So there is some sort of "Jurassic Park"-style biology going on to bring back some of those species. However, there are situations where species go extinct in the wild, but then can be reintroduced later after some sort of captive breeding project. One of the most exciting, to entomologists, at least, examples of this has to do with a creature called the tree lobster, a giant stick insect found on Lord Howe Island in the Tasman Sea, and considered extinct for over a century until a few dozen individuals were found eking out a tiny existence on a rocky spire just off the coast.
They were gathered, they were bred in captivity, and they now number in the thousands. And biologists are just waiting for the day they can reintroduce them to Lord Howe Island after they eradicate the rats that got them into trouble in the first place.
@yourfriendTina asks, why is wildlife conservation as a career kind of looking sexy rn? Well, is it looking sexy? That's great news for wildlife conservationists. The field of wildlife conservation may appear sexy or may appear booming to you right now because it's more important than ever before.
As wild areas, and natural areas, and biodiversity diminish, the role of conserving what's left becomes more and more important. And we do have some success stories to look to and to inspire us as well. Consider, for example, the California Condor-- nearly extinct decades ago, so rare that the last few individuals were trapped from the wild, bred in captivity for decades, and are now slowly being released back into their former habitat-- flying over Northern California, places where their huge wing spans have been missing for decades. So those are all the questions we have for today-- a wonderful mixture of questions, by the way. Thank you for watching "Biology Support."