The Burrowers Below
Eveline Vouillemin takes us deep into the lairs of animals that spend their days and nights underground.
Article by: Eveline Vouillemin
Artwork by: Alicia Hayden
Meerkats make their homes in burrows built by other animals.
In the face of nature’s continual challenges, various species have evolved in remarkable ways to ensure their survival. Whether it’s the intricately woven nests of weaverbirds or the sturdy dams constructed by beavers, no adaptation is as mysterious as the burrow - a concealed sanctuary below the ground.
A burrow is a hole or tunnel that an animal digs for various purposes and can be created in a range of different habitats. They are popular among many types of animals, including invertebrates, and come in a wide range of shapes and sizes, from short, simple tubes to elaborate, complex networks of connected chambers and tunnels.
Some animals use burrows as shelter from predators and extreme weather conditions, as locations to store food, and as nesting grounds for pregnant mothers to give birth and rear their offspring.
There are three types of burrowing animals:
Primary excavators: these animals dig their own burrows.
Secondary modifiers: these animals use burrows made by other animals and may modify them to suit their needs.
Simple occupants: these animals occupy abandoned burrows and do not modify them.
All burrowing animals are resourceful and have physical characteristics and adaptations which enable them to thrive in environments where life beneath the ground is the key to their survival. These creatures have evolved a diverse range of strategies for burrowing, each tailored to their specific needs and environments.
We will now dig a little deeper into the lives of six fascinating burrowing animals:
1.Platypus
A platypus will dig a simple, temporary burrow near a body of water, for nesting and resting.
The platypus is a unique, semi-aquatic, egg-laying mammal which can only be found in freshwater habitats in eastern Australia (including Tasmania). They have a duck-like bill, the tail of a beaver, webbed feet like an otter, and lay eggs – but they are still mammals.
Platypuses don't create traditional burrows but rather dig simple, temporary burrows or tunnels in the banks of water bodies. These burrows serve as nesting and resting places and are usually short with a single entrance and exit.
Female platypuses dig a waterside nesting burrow in which to lay their eggs. After 10 days, the babies hatch and remain in the burrow for around four months before leaving the burrow and leading independent lives. These burrows are essential for their reproductive and survival needs, allowing them to raise their young in a safe and concealed environment.
Platypuses are also considered a keystone species (a species which affects the survival and abundance of many other species in the habitat in which it lives) because they play a vital role in food chains, feeding on insect larvae, annelid worms, freshwater crayfish and shrimp, and being consumed by birds of prey, crocodiles, snakes and other predators.
2.Meerkat
Meerkats often make their homes in burrows built by other animals, expanding them to create intricate burrow systems.
Meerkats are small, social mammals belonging to the mongoose family native to the arid regions of southern Africa, including Zimbabwe, Botswana, and Mozambique. A colony of meerkats, averaging 20 to 30 members, is known as a ‘mob’, ‘gang’, or ‘clan’ and inhabits areas such as open plains, grasslands, and scrublands.
Often making their homes in burrows built by other animals, typically ground squirrels or mongooses, they move in and expand the environments to create intricate burrow systems. A meerkat burrow can have as many as 90 entrances and be up to two metres deep. These extensive burrows have a dozen or more exits, as well as sleeping and toilet areas.
The meerkats only leave their burrow during the day and take turns standing guard at entrances - watching for potential threats while others in the gang forage for food or play. The moment a guard spots a potential threat, they raise the alarm via a warning bark and the other gang members will scatter to the many tunnels and chambers of their burrow.
3.Aardvark
Aardvarks are reclusive animals, who build complex burrow systems to protect themselves.
Aardvarks are nocturnal mammals found in the rainforests, savannahs, woodlands, and scrublands of Africa. They are known for their distinctive appearance with long snouts, large ears, and powerful shovel-shaped claws. These are well-suited to excavating the hard, compacted soils found in many African regions.
Their burrows can be quite complex with multiple chambers and entrances and provide aardvarks with protection from predators and extreme weather conditions, as well as a place to give birth and raise their young. Burrows are an integral component of their survival strategy as they have poor eyesight and are known as cautious and reclusive animals.
Before leaving the protection of their burrows, aardvarks typically stand for several minutes at the entrance to ensure that predators aren’t waiting to attack them. Also, whilst sleeping, aardvarks block the entrance to their burrow and coil into a tight ball. If they are attacked in the burrow, they will typically seal the tunnel off behind them.
Aardvarks are considered a keystone species because many mammals and insects use their abandoned burrows for protection from predators, shelter from the extreme heat, and to bring up their young.
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Fun Fact: Burrowing animals are found on every continent except Antarctica.
4.Groundhog
Groundhogs are exceptional burrowers and play an important role in maintaining soil health.
Groundhogs, also known as woodchucks, are exceptional burrowers and are primarily found in the eastern United States. Their burrows are particularly large and elaborate, and can extend several feet underground. These burrows are usually located in grassy or open areas, making it particularly easy for the groundhogs to access their foraging grounds and observe their surroundings.
The groundhog plays a very important role in maintaining healthy soil in woodland and plain areas. Their burrows create channels which allow air and water to penetrate deeper into the soil. This promotes the growth of beneficial soil microorganisms and improves soil structure. Their foraging and excretion also contribute to nutrient cycling in the ecosystem which can enhance soil fertility and promote plant growth.
Groundhogs also enter true hibernation - one of the few species to do so. They will often build a separate ‘winter burrow’ for this purpose and have been known to share space in their burrowing network with other hibernating species over winter, such as rabbits, skunks, and raccoons.
5.Prairie Dog
Prairie dogs create extensive burrow networks, which can be identified by the mounds of earth left near the entrance.
Prairie dogs, native to the grasslands and prairies of North America, are small, social rodents which create one of the world's most extensive burrow networks. Prairie-dog burrows can stretch more than 64,000 square kilometres, have more than 400,000 individual members, and are often identified by the particular mounds of earth left near the entrances of their burrows.
In the 19th and 20th centuries, ranchers and government agencies used poison to try to eradicate prairie dogs because their burrow networks are often found on land where livestock graze - putting cattle, goats, and sheep at risk of injury. The few prairie dog towns which exist today are mostly found in national parks and conservation areas.
Prairie dog colonies have a significant impact on their ecosystems. They help maintain the grasslands by trimming vegetation and promoting plant diversity by encouraging the growth of forbs (or phorbs), such as sunflowers and clover. The abundance of forbs attracts animals such as bison and provides more nutrient-rich food for livestock. Their burrows can also benefit other wildlife species, providing shelter for burrowing owls, snakes, and insects.
6.Burrowing owls
Burrowing owls are one of only a few bird species which occupy burrows rather than making a nest.
Burrowing owls are one of the smallest owl species and one of several bird species which dig burrows rather than making nests. While puffins, kingfishers, and some types of penguins also make burrows, burrowing owls are unique among the order Strigiformes for their burrowing habits.
Found in both North and South America, they live primarily in deserts, grasslands and other open habitats. They typically occupy abandoned burrows built by prairie dogs, squirrels, desert tortoises, and other animals. However, if there is no deserted burrow available, they will create their own.
In addition to using burrows for nesting, resting and shelter, the owls use them to store food for their new offspring. Some stores have been uncovered containing hundreds of rodent carcasses.
Burrowing owls are also important components of their ecosystems and are often considered beneficial due to their role in controlling insect populations and as indicators of grassland health. Because the species depends on intact grassland ecosystems, the presence and well-being of burrowing owls can reflect the overall health of the grasslands.
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The burrowing behaviours of these six remarkable creatures enable them to thrive in their respective ecosystems and whilst their underground networks may be hidden, their benefits are wide-reaching.
They play an essential role in food chains, contribute to nutrient cycling, maintain healthy soil, promote plant diversity and create shelter for other animals. The protection of these animals and preservation of their habitat is vital - what goes on below ground has a monumental impact on the world above.
This article was written as an online exclusive, as part of our Volume 4: Hidden Worlds series.
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