Breathing seems simple until you consider what a pangolin faces. Each night, this scaly mammal spends hours excavating termite mounds, pressing its armoured face into narrow tunnels where oxygen levels drop and carbon dioxide accumulates. It breathes air laden with fine soil particles, fungal spores, and the chemical signals of insect colonies. Its respiratory system must support bursts of intense muscular activity during digging, recover rapidly during rest, and cope with the aerobic demands of carrying a bodyweight in scale armour across variable terrain. The anatomy of the pangolin's lungs and airways is built around these demands.
Upper Respiratory Tract: Nasal Passages and Adaptations
The pangolin's external nares (nostrils) are positioned at the tip of a long, tapered snout. This placement is functionally important: it keeps the nostrils away from the ground surface during feeding and allows the animal to probe into mound entrances while keeping its face at a safer distance from defensive insect swarms.
Internally, the nasal passages are lined with a well-developed turbinate system — scrolled bony structures covered in mucous membrane that warm and humidify incoming air before it reaches the trachea and lungs. The pangolin's olfactory epithelium, spread over an expanded section of the nasal cavity, is among the most well-developed sensory surfaces in the head, reflecting the central role of smell in locating insect colonies and navigating the environment at night.
Nostril Closure
A notable adaptation is the pangolin's ability to partially or fully close its nostrils using a ring of specialised muscular tissue around each naris. This closure is employed during mound excavation to prevent the inhalation of fine soil particles, ant acid, and chemical irritants. The ability to seal the nostrils does not trigger immediate breath-holding — pangolins breathe through a brief nasal-closure cycle, opening to inhale and exchange gas, then closing again before re-entering the mound.
Trachea and Bronchi
The trachea is a cartilage-reinforced tube running from the larynx through the neck and into the thoracic cavity, where it bifurcates into left and right main bronchi. In pangolins, the tracheal cartilage rings are complete and robust, providing structural support against the compressive forces that could arise when the animal rolls into a defensive ball, compressing the thorax between the tail and the body.
The larynx in pangolins is relatively simple. Pangolins are not known for vocal communication — they are among the least vocal of all mammals — and the laryngeal architecture reflects this. There is no complex syrinx or specialised vocal fold system. The primary laryngeal function is airway protection during swallowing, preventing misdirection of food (or insects) into the airway.
Lung Architecture: Lobes and Morphology
Pangolin lungs follow the standard mammalian pattern of lobed organs seated within the pleural cavities on each side of the mediastinum. The right lung is typically divided into more lobes than the left (which must share thoracic space with the heart positioned slightly to the left). Precise lobe counts and morphology vary between species and have not been exhaustively documented across all eight extant pangolin species, but the general pattern follows what is seen in comparable-sized insectivorous mammals.
The lung parenchyma (functional tissue) is composed of millions of alveoli — tiny air sacs surrounded by capillary networks across which gas exchange occurs. Oxygen in inhaled air diffuses across the thin alveolar walls into capillary blood, while carbon dioxide produced by cellular metabolism diffuses in the opposite direction for exhalation. In pangolins, the alveolar surface area relative to body mass is consistent with a mammal of their metabolic rate and activity level, though precise measurements are lacking for most species due to the difficulty of obtaining specimens for detailed anatomical study.
Respiratory Design Constraint
The pangolin's thoracic cavity is partially constrained by the heavy scale armour overlying the dorsal surface and flanks. This means the ribcage and diaphragm must do relatively more work in expanding the lungs, since scale-covered surfaces resist external deformation. The respiratory muscles are correspondingly well-developed.
The Diaphragm and Breathing Mechanics
Like all mammals, pangolins breathe using a muscular diaphragm — a dome-shaped sheet of muscle separating the thoracic and abdominal cavities. Contraction of the diaphragm flattens it, increasing thoracic volume and drawing air into the lungs (inspiration). Relaxation allows the diaphragm to recoil upward, reducing thoracic volume and pushing air out (expiration).
The intercostal muscles between the ribs assist with both inspiration and expiration, particularly during exercise. In pangolins, the intercostal muscles must work against the resistance of the dorsal scale arrays, which create a stiffer thoracic wall than is seen in most mammals. This is one reason why pangolins adopt specific postures during rest — allowing the flexible ventral surface to move freely for respiration rather than fighting against the rigid dorsal armour.
Breathing Rate
Resting respiratory rates for pangolins have not been systematically documented across all species, but observations in captive animals suggest rates roughly consistent with other medium-sized mammals — perhaps 15 to 30 breaths per minute at rest, rising substantially during and immediately after digging activity. Pangolins also exhibit periods of reduced activity and possible torpor-like states during which respiratory rate drops significantly, reducing caloric expenditure during the heat of the African or Asian day.
Gas Exchange During Mound Excavation
Termite mound interiors are oxygen-depleted relative to ambient air. Active termite colonies consume oxygen in large quantities to fuel their own metabolic activity, and large mound interiors can have oxygen concentrations several percentage points below the atmospheric norm of 21%. Carbon dioxide concentrations are correspondingly elevated.
Pangolins deal with this by spending relatively brief periods inside active mound excavations, alternating between bouts of digging and withdrawal to the surface for gas exchange. The closed-nostril adaptation helps minimise exposure to irritants, but does not prevent CO₂ buildup in the blood during extended mound access. The animal's chemoreceptor system — monitoring blood CO₂ and pH — drives the animal back to fresh air when carbon dioxide tension rises to trigger increased drive to breathe.
| Scenario | Respiratory Challenge | Pangolin Response |
|---|---|---|
| Active digging | High O₂ demand, elevated CO₂ production | Increased breathing rate after withdrawal from mound |
| Inside mound | Low O₂ / elevated CO₂ environment | Brief exposure periods; nostril closure limits irritant inhalation |
| Defensive ball | Thoracic compression limiting chest expansion | Shallow respiration; diaphragm-dominant breathing |
| Daytime rest | Low metabolic demand, thermoregulatory stress | Slow, deep breaths; possible torpor-like hypometabolism |
| Nocturnal travel | Moderate sustained aerobic demand | Regular rhythmic breathing supporting walking and climbing |
Respiratory Adaptations of Tree Pangolins
Tree-dwelling pangolins — the African tree pangolin (Phataginus tricuspis) and long-tailed pangolin (Phataginus tetradactyla) — face a different set of respiratory challenges than their ground-dwelling counterparts. Climbing demands sustained postural work that compresses the thorax at various angles, requiring the respiratory musculature to adapt to different mechanical loading conditions during breathing.
Tree pangolins also encounter arboreal ant colonies inhabiting hollow branches. Extracting insects from these enclosed woody spaces presents a different microenvironment than a soil mound — often drier, with different airborne chemical profiles. The nasal turbinate system's ability to manage humidity of inhaled air is therefore variably engaged depending on the habitat the individual species occupies.
Respiratory Disease in Captive Pangolins
Respiratory illness is among the most common causes of death in captive pangolins. Animals imported through the illegal trade frequently arrive dehydrated, malnourished, and immunocompromised, making them highly susceptible to bacterial and fungal respiratory infections. Aspergillus species (fungal organisms capable of causing aspergillosis) are particularly dangerous — they can infect damaged lung tissue and spread rapidly in an already-stressed animal.
Veterinary respiratory assessment in pangolins uses auscultation (listening with a stethoscope), thoracic radiography, and where possible bronchoalveolar lavage (washing the airway with saline and collecting the fluid for culture and cytology). Treatment with antifungals and supportive nebulisation (inhaled moisture and medication) has improved outcomes for some animals in specialist care facilities.
Captive Care Note
Stress significantly increases susceptibility to respiratory infection in pangolins. Minimising handling, maintaining appropriate temperature and humidity, and providing hiding places that allow the animal to roll up safely are among the most effective preventive measures in rehabilitation settings.
The Respiratory System in the Context of Pangolin Conservation
Understanding the pangolin's respiratory anatomy has direct practical applications. During veterinary procedures requiring anaesthesia, correct placement of the endotracheal tube requires knowledge of laryngeal and tracheal anatomy. The relatively narrow trachea in smaller species limits the size of tube that can be safely placed without causing mucosal injury.
For field biologists using chemical immobilisation to fit GPS tracking collars or collect blood samples, monitoring respiratory rate and depth provides a primary indicator of anaesthetic depth and animal safety. Pangolins under field anaesthesia are monitored continuously for respiratory arrest, and reversal agents are kept on hand to restart breathing if it becomes dangerously depressed.
Beyond individual animal care, protecting pangolin populations preserves the ecological role these animals play in aerating soil and controlling insect populations — functions tied directly to the energetic demands that have shaped their respiratory architecture over millions of years of evolution.
Frequently Asked Questions
Can pangolins close their nostrils?
Yes. Pangolins have muscular sphincters around their nostrils that allow partial or complete closure. This adaptation protects the respiratory tract from soil particles, ant acid, and chemical irritants during mound excavation.
How do pangolins breathe when rolled into a ball?
In a defensive ball, the thoracic cage is compressed. Pangolins rely heavily on diaphragmatic breathing in this posture — the muscular diaphragm generates most of the respiratory effort since intercostal expansion is restricted.
How does the low oxygen inside a termite mound affect pangolins?
Termite mound interiors have elevated CO₂ and reduced O₂ compared to ambient air. Pangolins manage this by spending short bursts inside mounds, withdrawing regularly to breathe fresh air. Rising blood CO₂ drives the urge to return to the surface.
What respiratory diseases affect pangolins?
Bacterial and fungal pneumonias are the most common respiratory killers in captive pangolins, particularly aspergillosis in immunocompromised animals. Stress, malnutrition, and dehydration (common in trafficking survivors) dramatically increase susceptibility.
Do pangolins make sounds?
Pangolins are among the least vocal mammals. The larynx is relatively simple with no specialised vocal anatomy. Some sniffing, hissing, and soft grunting sounds have been recorded, but pangolins do not use vocalisations as a primary communication channel.
How does the scale armour affect pangolin breathing?
The rigid dorsal scale arrays limit expansion of the thoracic cage on the scale-covered surfaces. Pangolins compensate with strong diaphragmatic and intercostal musculature. They also rest in postures that free the flexible ventral surface for easier respiratory movement.
The pangolin's respiratory system is a study in adaptation to constraint. Working within the limits imposed by heavy scale armour, a specialist diet requiring extended time in oxygen-poor environments, and a nocturnal lifestyle demanding efficient recovery between bouts of intensive digging, the pangolin's lungs and airways have evolved a suite of structural and behavioural solutions that allow this remarkable animal to thrive in habitats across Africa and Asia. Each breath it takes is a small testimony to the elegance of natural selection — and a reminder of what is at stake as all eight pangolin species face existential pressure from poaching and habitat loss.