From the first claw-stroke to a sealed entrance, how pangolins construct, use, and share their subterranean refuges
Of all the physical structures that wildlife engineers produce, the pangolin burrow is among the most underappreciated. Termite mounds attract admiration for their climate-controlled architecture. Beaver dams get recognition as ecosystem-modifying constructions. Pangolin burrows, by contrast, tend to be noted in the field literature as little more than "refuges" — as though the animal simply retreated into a hole in the ground. The reality is more interesting. Pangolin burrows are species-specific, site-selected, thermally buffered shelters that double as maternity chambers and, long after abandonment, as critical habitat for dozens of other species.
Ground-dwelling pangolin species — primarily the ground pangolin (Smutsia temminckii) and the giant ground pangolin (Smutsia gigantea) — are built for excavation. Their forelimbs are massively developed relative to body size. The three functional digging claws on each forefoot are among the largest, relative to body length, of any mammal that constructs self-excavated burrows. In a mature ground pangolin, the central claw may reach 60–70 mm in length.
Digging technique is distinctive. The pangolin begins by using its forefeet to loosen soil in alternating strokes, swinging each foreleg in a wide arc and driving the claws deep into the substrate. The loosened material is pushed backward under the body and swept clear of the excavation zone with the hindlimbs, a motion that researchers describe as "backward scrabbling." The tail is used as a prop and balance organ during digging, braced against the tunnel wall or the surface behind the animal.
Burrowing speed depends heavily on substrate. In sandy loam — the preferred soil type — a ground pangolin can excavate at approximately 0.5 to 1 metre per hour during active digging phases. In clay-rich soils, progress slows substantially. Substrate preference is not random: pangolins consistently select sites with friable, well-drained soils that maintain structural integrity without requiring reinforcement. This limits burrow collapse risk during the long periods when the animal is resting inside.
Published measurements of ground pangolin burrows vary by habitat and individual, but certain structural patterns are consistent across field studies in South Africa, Zimbabwe, Botswana and Kenya. The entrance shaft descends at an angle of 30 to 45 degrees from horizontal, spiralling or curving within the first metre in a way that breaks line of sight from the surface. This bend is not incidental — it blocks draughts, reduces predator ingress, and creates a light-trap that keeps the interior dark regardless of external light levels.
Total tunnel length typically ranges from 2 to 5 metres for regularly used burrows, with some outliers recorded up to 7 metres in deep sandy soils. Depth to the resting chamber floor ranges from 0.5 metres in shallow seasonal shelters to 1.5–2.5 metres in primary residential burrows. The chamber at the end is enlarged relative to the tunnel, forming a roughly spherical or oval space large enough for the animal to turn around in — approximately 40–60 cm in diameter.
Some individuals maintain multiple burrows within their home range and rotate use, returning to the same set of sites over months or years. GPS telemetry studies in the Tswalu Kalahari Reserve in South Africa have documented individual ground pangolins using 6 to 14 distinct burrow sites, with residence times at any single burrow ranging from one to several nights. The selection pattern is not random: animals tend to return to burrows near productive foraging areas and avoid sites disturbed by large ungulates or human activity.
| Parameter | Typical Range | Maximum Recorded |
|---|---|---|
| Entrance diameter | 20–25 cm | ~30 cm (giant ground) |
| Tunnel length | 2–5 m | ~7 m |
| Chamber depth (floor) | 0.5–2.5 m | >3 m (estimated) |
| Chamber diameter | 40–60 cm | ~80 cm (giant ground) |
| Tunnel angle (entrance) | 30–45 deg below horizontal | ~60 deg in steep terrain |
Pangolins have low metabolic rates and limited thermoregulatory capacity relative to other mammals of similar size. They do not shiver effectively, cannot sweat, and have reduced brown adipose tissue for non-shivering thermogenesis. Their body temperature can fluctuate by 7–10°C over a 24-hour cycle without physiological crisis — a degree of heterothermy unusual in placental mammals but critical to their energy budget.
The burrow functions as a passive thermostat. At depths of 1 to 2.5 metres, soil temperature in southern African habitats remains buffered against surface extremes: cooler than the surface during midday summer heat, warmer than ambient during winter nights. Measurements taken inside ground pangolin burrows in the Tswalu system showed internal temperatures consistently within the animal's thermal comfort zone (approximately 22–28°C) when surface temperatures ranged from 8°C at night to 42°C at midday.
In winter months, this buffering is energetically critical. A pangolin sheltering at 1.5 metres depth maintains a warmer ambient temperature than it would experience at the surface or in a surface nest, reducing the energy cost of maintaining core body temperature through a 10–12 hour inactivity period. Over a season, this thermal subsidy represents a meaningful fraction of total energy expenditure saved — energy that can be redirected toward reproduction, immune function, or fat reserves.
One behaviour that puzzled early researchers is the pangolin's habit of plugging the burrow entrance from the inside after entering. The animal backs into the tunnel after descending, then uses its tail and hindquarters to press a mass of soil against the entrance, effectively sealing it. The plug is not always complete — in warm weather, a partial seal that maintains ventilation is common. In cold weather, complete sealing is more typical.
The adaptive value is clear on reflection. A sealed entrance eliminates draughts, conserves heat, and presents a formidable physical barrier to predators attempting entry. A lion, leopard, or hyena confronting a plugged pangolin burrow faces a compressed soil mass backed by a pangolin's armoured tail — a combination that has been observed to deter even determined predator investigation. Several telemetry studies have recorded attempts by large carnivores to excavate pangolin burrows, with the excavation abandoned before reaching the animal.
Pangolin burrows are ecosystem services. Once excavated — particularly by giant ground pangolins, which produce the largest and deepest shelters — these structures attract a diverse community of secondary users. Research in savanna systems across southern and eastern Africa has documented substantial burrow co-use by:
The ecological function of pangolin burrows as habitat providers makes the decline of burrowing pangolin species a concern not only for the pangolins themselves but for the entire community of species that depend on their engineering. In landscapes where ground pangolins have been locally extirpated by hunting pressure, researchers have noted reduced burrow availability for warthog breeding and wild dog denning — a trophic cascade effect that has received almost no systematic study.
Tree pangolins — the white-bellied and black-bellied pangolins of Central and West Africa — do not construct burrows. They rest in tree hollows, in the crowns of dense tangles of lianas, or coiled on large horizontal branches, relying on their scales and cryptic immobility for protection rather than underground concealment. The thermoregulation challenge for arboreal species is different: the forest canopy moderates temperature extremes, and the animals' restricted range within the forest interior limits exposure to the cold nights common in open savanna.
This distinction has significant implications for habitat assessment. Evaluating ground pangolin habitat quality requires not only food availability data but burrow suitability mapping — information on soil texture, depth to impermeable layers, and substrate compaction that determines where functional burrows can actually be excavated. Sites with abundant ant and termite colonies but overlying hard laterite or shallow bedrock cannot support resident ground pangolins regardless of food supply.
Female ground pangolins give birth to a single pup after a gestation of approximately 139 days. The birth typically occurs in a burrow that is longer and deeper than the animal's typical daytime shelter — what field researchers term a maternity burrow. The pup, born with soft, pliable scales that harden within days, remains in the burrow for the first 3–4 weeks, after which the mother begins carrying it on her tail when she forages at night.
Maternity burrows show distinct characteristics: they tend to be oriented away from prevailing wind, located in terrain with good drainage to prevent flooding, and are often reused across multiple breeding seasons. A female's association with specific maternity sites may persist for years, suggesting site fidelity to burrows that have proven reliable for pup survival. Identifying and protecting known maternity burrows is therefore a conservation measure with multiplied benefit — the same site may contribute to multiple breeding events over a decade or more.
Ground pangolin burrows typically reach 0.5 to 2.5 metres depth for the resting chamber floor, with some deep sandy-soil burrows estimated at over 3 metres. Giant ground pangolin burrows tend to be larger in all dimensions than those of the smaller ground pangolin species.
No. Only ground-dwelling species — primarily the ground pangolin and giant ground pangolin — construct self-excavated burrows. Arboreal species such as the white-bellied and black-bellied pangolin rest in tree hollows or vegetation tangles and do not burrow.
Sealing conserves heat, eliminates draughts, and deters predators. An animal plugging the entrance from inside with its tail and hindquarters presents a formidable physical barrier that has been documented to deter predators including lions and hyenas.
Secondary users include warthogs (for birthing and shelter), aardvarks (as starter excavations), Cape porcupines, African wild dogs (for denning), monitor lizards, various snakes, and some bird species. Pangolin burrows are an important ecosystem resource for biodiversity beyond pangolins themselves.