Dozens of animal species live in burrows, from tiny spiders to large marsupials. Mammals, birds, reptiles, amphibians, and invertebrates all use underground tunnels for shelter, nesting, temperature control, and protection from predators. Some dig their own elaborate tunnel systems, others move into burrows abandoned by different species, and a few spend nearly their entire lives beneath the soil.
Prairie Dogs and Their Underground Towns
Black-tailed prairie dogs are among the most impressive burrowers on Earth. Their tunnel systems, called towns, are U-shaped networks of chambers connected by passageways that reach 7 to 15 feet deep. Each burrow has multiple entrances, giving the animals escape routes if a predator gets inside. Mounds of excavated earth around each entrance double as flood barriers, keeping water from pouring in during rainstorms.
The design of a prairie dog town is surprisingly intentional. Near the bottom sits a nesting chamber lined with dry grass bedding. Closer to the surface, smaller “listening chambers” let prairie dogs pause and check for danger before stepping outside. Beyond sheltering their residents, these towns reshape the landscape. Prairie dogs bring deep soil to the surface and their tunnels aerate the ground, which benefits plant growth across the surrounding grassland.
Moles: Speed Diggers of the Lawn
Moles can extend their shallow surface tunnels at a rate of about 100 feet per day. Their burrow systems come in two types: surface runways just beneath the top layer of soil (the ones that leave visible ridges in your yard) and deeper permanent tunnels used for nesting, resting, and traveling between feeding areas. A single mole can maintain an extensive network of interconnected tunnels, spending almost its entire life underground hunting earthworms and grubs by feel.
Wombats and Their Massive Warrens
Common wombats dig some of the largest burrows of any living animal. A single burrow can stretch upward of 15 meters (about 50 feet) in length, with multiple entrances and deep, multichambered layouts. These aren’t simple holes in the ground. Wombat warrens are complex enough to serve as emergency shelters for other wildlife. Research published in the Journal of Mammalogy found that wombat burrows act as hotspots for small vertebrates in landscapes affected by wildfire, giving lizards, small mammals, and other animals a fireproof refuge when the surface becomes deadly.
Gopher Tortoises: Landlords of the Animal World
The gopher tortoise of the southeastern United States is considered a keystone species largely because of what its burrows do for other animals. A single tortoise digs a long, deep tunnel that provides shelter, foraging habitat, and nesting sites for over 60 vertebrate species and more than 300 invertebrate species. Snakes, mice, frogs, insects, and even burrowing owls move in alongside the tortoise or take over after it leaves.
What makes gopher tortoise burrows especially valuable is that the community of animals using them doesn’t change much based on whether the tortoise is still living there. Researchers studying 125 tortoise burrows found that the mix of vertebrate species was essentially the same across active, inactive, and fully abandoned burrows. Once the tunnel exists, the ecosystem it supports persists.
Burrowing Owls
Not all burrowers are mammals. Florida burrowing owls typically dig their own tunnels, which run 5 to 10 feet long and can be excavated in as little as two days. The entrance averages about 5 inches wide by 3.5 inches tall, often with a pile of kicked-out soil at the opening. When they don’t feel like digging, these owls happily move into burrows originally made by armadillos, gopher tortoises, or iguanas. They’ve also been found nesting in manholes, sewer drains, and concrete pipes.
Platypuses and Their Waterside Tunnels
Platypuses maintain two different kinds of burrows along riverbanks, each built for a specific purpose. Resting burrows are short, casual shelters dug close to the water’s edge, often with entrances right at the waterline or even underwater. Nesting burrows are a different story. Females dig these significantly higher above the river (about 2 meters up the bank versus 1 meter for resting burrows) and much farther from the water’s edge (roughly 9 meters versus 5 meters). Nesting burrows can stretch 4 to 9 meters in length. The extra distance and elevation protect eggs and young from flooding.
Rats: The Urban Burrower
Norway rats, the brown rats common in cities worldwide, dig surprisingly organized burrow systems beneath buildings, gardens, and sidewalks. A typical rat burrow sits no deeper than 18 inches below the surface and includes separate areas for food storage and living space. Most have one main entrance plus one or two concealed bolt holes connected by about 3 feet of tunnel, giving the rats a quick escape when threatened. If you spot a rat-sized hole near your foundation with smooth, well-worn edges, you’re likely looking at an active entrance.
Why Burrows Stay Cool in Extreme Heat
One of the biggest advantages of burrowing is temperature control. In desert environments, the difference between the surface and just a short distance underground is staggering. Researchers studying rodent burrows in China’s Mu Us Desert recorded surface temperatures hitting 61.8°C (143°F), while inside burrows at just 15 centimeters deep, the maximum temperature was only 31°C (88°F). The daily temperature swing on the surface was over 46°C. Inside the burrow, it was just 7.5°C.
This thermal buffering is a survival necessity. The same study found that gerbils living on the desert surface would face 4 to 11 hours of dangerous heat stress per day during summer. Inside their burrows, they experienced essentially none. This principle applies broadly: from ground squirrels in the American West to monitor lizards in Australia, burrowing animals avoid lethal temperature extremes by staying just a few inches underground during the hottest and coldest parts of the day.
Invertebrates That Live Underground
Some of the most patient burrowers are invertebrates. Periodical cicada nymphs spend 13 or 17 years underground, living at depths of 2 to 24 inches while feeding on sap from tree roots. When their emergence year arrives, nymphs tunnel up to about an inch below the surface in April and wait. Once the soil temperature hits 64°F, they climb out and up the nearest vertical surface to shed their exoskeletons and begin their brief adult lives.
Trapdoor spiders take a different approach entirely. Rather than simply digging a hole, they construct silk-lined tunnels fitted with a hinged door at the entrance. The lid is camouflaged with soil and plant debris to blend perfectly with the surrounding ground. The spider waits just behind the door, sensing vibrations from passing prey, then flips the trapdoor open to grab its meal before retreating back inside. Some trapdoor spiders live in the same burrow for decades.
Other Notable Burrowers
- Rabbits dig interconnected warrens with multiple chambers for nesting and escape, sometimes housing dozens of individuals in a single system.
- Badgers excavate large, multi-generational tunnel networks called setts that can be used by the same family for over a century.
- Kingfishers nest in horizontal burrows dug into riverbanks, carving out a tunnel with a rounded nesting chamber at the end.
- Tarantulas in arid regions dig vertical shafts lined with silk, using them as both homes and ambush sites.
- Foxes dig dens called earths, though they also frequently enlarge and reuse rabbit or badger burrows rather than starting from scratch.
Burrows are one of the most common and effective survival strategies in the animal kingdom. They provide protection from predators, insulation from extreme weather, safe spaces for raising young, and in many cases, benefits that extend far beyond the original digger to entire communities of species that depend on the shelter someone else built.