When you think of an engineer, you may picture people who have jobs building bridges or designing computers. But in the natural world, engineers are often a lot more fuzzy! For example, beavers are well-known “ecosystem engineers.” They are given this name because they physically change their environment in a way that creates habitat for other species in the area.

Beavers are small mammals equipped with webbed feet, sharp teeth, and flat, rudder-like tails that live mostly in northern continents near streams, rivers, and other bodies of freshwater. When beavers don’t have access to slow, deep water, they will make their own by building dams out of trees they’ve cut down as well as branches and mud they have gathered. Beavers build their homes or “lodges” in the water near their dams, which provides them with a protected space to live and raise their young. However, the effect of these dams extends far beyond the beaver.

Beaver dams are large, and physically block water flow. This creates a big area of standing water, or water that doesn’t move very much. These areas are called “beaver ponds.” In shallow valleys, beaver dams can create a large area of wetland that wasn’t there before. Wetlands and standing water tend to support a lot of life, like invertebrates that need calm water for their life cycles, bacteria that thrive in silt, aquatic plants that couldn’t live in fast moving water, as well as birds and fish that prey on these species. These habitats have even been found to reduce levels of toxins and pesticides in the water, because microorganisms and plants have time and space to break them down. Beavers change their habitat for their own benefit, but many other species are also supported by their engineering.

Ecosystem engineers can also look scaly! The gopher tortoise is another well-known ecosystem engineer. In the southern US, these tortoises dig large burrows to protect themselves from predators and extreme weather, which can be as long as 25 feet and as deep as 10 feet. Beetles, moths, caterpillars, snakes, and frogs in the region have been documented to use the tunnels at some point in their lives. In fact, about 300 species have been found to use the burrows, or the mounds of sand created from the tortoises digging them out.

In this way, beavers, gopher tortoises, and other engineers create crucial habitat for many species. Conservation scientists often focus on protecting populations of ecosystem engineers because this in turn protects many species around them.