Did you know that some animals are excellent engineers? Did you know that if a tree falls in a forest, a beaver hears the sound? Did you know that Spiderman is capable of being an awesome engineer? Did you know that some birds build stick castles for the ladies? Time to learn about some amazing animals!
This orangutan is also a good engineer. From Mechanix Illustrated, November 1950.
First up is the quintessential wildlife engineer – the beaver. Beavers have been building dams for a lot longer than humans. Using their large teeth, these large, semi-aquatic rodents are capable of chopping down trees and maneuvering large limbs to create dams and lodges. A beaver lodge is a home made of branches, sticks, and mud. Lodges often contain an underwater opening and are a good place to raise young. Beavers will usually eat bark, twigs, leaves, and other plants. Their tail looks like a large pancake (tastes good with maple syrup) and acts like a rudder while swimming. Beavers sometimes slap their tails against the water and create a loud signal that carries across the water and warns other beavers of potential danger. I’m not sure if that includes Justin Beaver.
Beavers create dams to control the flow of water and to protect their homes. Having fast-flowing water rip through your lodge would not be fun for a beaver. Some dam systems are quite intricate and include series of canals! As you might guess, beaver engineering affects the local ecosystem in a major way. By cutting down specific trees and diverting the flow of water, beavers can impact a variety of ecological processes, plants, and other wildlife. For example, the systems of pools and waterways created by beavers can reduce flooding and soil erosion. Some plants and wildlife can thrive in the small wetlands that arise from beaver engineering. On the other hand, beaver activity may negatively affect organisms which rely on flowing water, and beaver dams have hurt some farming practices and trout fisheries. The largest beaver dam on record, is located in Alberta, Canada and is over 2700 feet in length!! That’s over twice as long as the Hoover Dam! Interestingly enough, the dam was first located using Google earth and satellite imagery! Researchers suggest that several beaver families may have contributed to this natural wonder.
Google Earth image of the largest beaver dam in the world.
Next up are spiders. Spiders are well known for creating intricate webs made of silk. If you are bitten by a radioactive spider, you just might gain superpowers and a strong desire to talk to yourself out loud. Spiderman normally uses his webbing to swing from building to building, entrap enemies, or break a fall. However, if he had studied engineering, he could create so many amazing things. On a side note, one of the most annoying things is to walk face-first into a spiderweb. During one morning doing bird surveys, I walked into about 50 spider webs and spent a lot of time pulling sticky webbing off my glasses. Anyway, Orb-weaving Spiders (Thousands of species in the Family Araneidae) design many of the familiar spiral webs to catch prey. There are usually circular sections of the web that are comprised of sticky silk, but the orb-weavers tiptoe across non-sticky lines throughout the web. When an insect (or occasionally something bigger!) gets stuck in the web, the spider comes out and cocoons the prey for a tasty meal. Many orb-weavers actually spin new webs almost every day! Many spider webs are quite beautiful, though people don’t often stop to appreciate them due to fear of creepy, crawly things.
Recent studies and explorations have led scientists to claim that the largest web in the world is produced by the Darwin’s bark spider. As is the case with many spiders, females are larger than males. Females are generally between 15 and 20 mm long, while males are around 5-6 mm long. Despite their tiny size, Darwin’s bark spider have been recorded creating webs over 25 meters across! The material of these webs is said to be stronger than steel or kevlar, which is used in bulletproof vests! The silk used in the webbing is also extremely elastic and resistant to breaking. Hmm . . . maybe I should create a vest out of spider webs so that I can fight crime. By spreading out tough webs over rivers, the spiders can catch insects that frequently use the water, such as dragonflies and mayflies.
Left – bark spider web spanning across a river (photo: Matjaž Gregorič). Right – Darwin’s bark spider (photo: Matjaž Gregorič)
I hope you find the creations of beavers and spider fascinating. Try to remember that most spiders are harmless and actually help control insect populations. Hold a pet tarantula if you need practice overcoming a fear of spiders. These animals really are amazing engineers! My next blog will spend time on bowerbirds and their efforts to create nests to impress! Now if you’ll excuse me, I’m going to slap some water with a tennis racket and spin a bulletproof web to catch some dinner.