Today's post is going to be more on the educational side. I'm going to be talking about the toughest animal on the planet.
Before we get started, if I were to ask you all what animal you thought was the strongest, most of you would probably say, I don't know, a lion or a shark, right? Well, it's actually something most people have never even heard of before. I know I didn't; the first time I read an article about it, I was super confused. The very animal my blog post is going to be about today is.... the tardigrade!
Let's start off with some general information about the tardigrade, and what makes it so special. First, a tardigrade is in fact an animal, although it may not look like an animal judging from the picture I have of it above. They have their own phylum, called the tardigrada. They are aquatic animals, but they can live virtually anywhere that is moist, such as soil or plants. Anatomy-wise, they have 8 legs with claws on each leg. Their mouths contain something called a stylet, which helps them pierce and eat food. Their diet consists of other microscopic organisms, bacteria, fluids of plant and animal cells, and they even participate in cannibalism; yes, they eat each other! They are really really tiny; they range from 0.05 to 1 millimeter length-wise. That means that with the naked eye, we CAN see the biggest tardigrades, although we would still need a microscope to view the details. As for reproduction, they can participate in both asexual AND sexual reproduction. Something different about the tardigrade is that when the young are born, the tardigrades will have adult cells. As they grow, the cells don't actually divide; they only enlarge to help the tardigrade overall grow in size. Each tardigrade can have their own offspring within two weeks of existence!
So far, scientists have discovered about 1000 species of tardigrades, but they speculate that there are over 10000 total.
Alright, so how is this tiny, fragile animal the toughest being on the planet? Get this:
They are able to survive in EXTREME conditions. I'm talking about areas like OUTER SPACE, people.
Yes, you heard me right: OUTER SPACE. No animal can survive there, except for the tardigrade. They are able to do this by transforming into something called a "tun."
If a tardigrade encounters bad conditions, they can enter a dehydrated state that resembles death. Remember when I said that the tardigrades need moist conditions to live. Well, when the environment they're in is super dry and therefore cannot support a tardigrade, they will morph into a tun. This process is called anhydrobiosis. Basically, tardigrades curl up into a little ball, which is their dormant state. Their metabolism slows and they're basically in a near death state. Anhydrobiosis involves the usage of trehalose, which is a sugar that protects the tardigrades from dehydration by preserving the organelles and membranes in the cells of the tardigrade. They can actually stay in this dormant state for up to 120 years! However, in their normal, active state, the most they can survive is 10 years. They change back into the normal state when returned to their ideal conditions. The more time a tardigrade remains as a tun, the less chance it'll be revived in its normal, functioning, alive state. This, ladies and gentlemen, is how a tardigrade is able to survive in space.
Here are some other ways tardigrades can survive. If the oxygen concentration of its aquatic environment drops, meaning there is less oxygen available for cellular respiration, tardigrades enter a state where their metabolic rate is reduced and their muscles relax which lets water and oxygen enter their cells. If the temperature is way too low for their liking, the tardigrade becomes a cold-resistant tun with molecules that stop the formation of ice crystals. This is important because ice crystals can damage their membranes.
Because of their amazing ability to survive in extreme conditions, some people think that tardigrades actually originated outside of Earth. But many scientists hypothesize that they did in fact come from Earth.
Now I want to quickly talk about some more interesting facts about the tardigrade. The average human consumes tardigrades on a daily basis because they are found everywhere - in leafy greens, in water, etc. However, they have little to no effect on humans when ingested, and the reason why is this: yes, it can survive harsh areas but you know one place a tardigrade cannot survive in? The human digestive system. These little animals don't fare well when they face stomach acid. They die in the stomach and therefore cause little harm to our bodies. So tardigrades can take up to 5000 times - yes, you read that correctly - 5000 TIMES the radiation that an average human being can, yet it doesn't do well with acid. One more cute little tidbit is that tardigrades are also known as waterbears, because they do in fact look like a bear and they do in fact live in aquatic conditions.
Super interested? Yeah, me too. Here's a video to help you better visualize the animal: www.youtube.com/watch?v=aHsVyb_VfeA
Hope you learned something. Happy Sunday!