There are over 5,000 species of cockroaches. They're a very successful and adaptable group of insects. They've been around for millions of years and will likely be around long after humans have vanished.
Overall, cockroaches are an important part of the ecosystem because they recycle dead matter and are a food source for other animals. But a few types of cockroaches enjoy living in human habitats and are not so welcome. These cockroaches have evolved to take advantage of the resources that humans unwillingly provide and are very good at surviving in our homes. This TED Ed video looks at these unlovable yet hardy creatures.
One reason they are hard to kill is that they are so darn quick. Their antennae can sense tiny air currents and they can sprint up to 50 body lengths per second. They can also squeeze into incredibly tight spaces because they can flatten their bodies.
Another reason is that they can survive on "food" like hair, dead skin, adhesives, and paper, because of their powerful digestive enzymes. When those tasty victuals aren't available, they'll feast on their own feces, vomit, and dying colony members. That sounds almost as gross as a Taco Bell at 2 AM on a Saturday night.
And because they reproduce so quickly, they can quickly develop resistance to pesticides.
One surprising thing I learned from watching this TED Ed video is that, contrary to popular belief, cockroaches are not very tolerant to ionizing radiation, and so they would not easily survive a nuclear attack.
The next time you see a cockroach, give it a nod of respect. It's one tough little customeromer