AnimaliaHighest rank in taxonomy. Groups all life into domains: Animalia, Plantae, Fungi, etc.IUCN VUInternational Union for Conservation of Nature — the world authority on species extinction risk, using standardized criteria. — Vulnerable — at high risk of extinction if the current adverse conditions continue.In ProgressCurrent stage of this record in the editorial review workflow. Recent Sighting
Ginglymostoma cirratum
Nurse Shark
(Bonnaterre, 1788)
Detailed Texts Multi-lang
The nurse shark presents an unmistakably robust, cylindrical morphology sublimely adapted to benthic life. Its body, slightly flattened dorsoventrally in the anterior section, culminates in a broad, blunt head. Adults exhibit a uniform coloration ranging from yellowish-brown to dark brown or grayish, while juveniles display a characteristic pattern of small dark spots that gradually fade with maturity. The skin is covered by extremely hard, densely packed dermal denticles that give it an exceptionally rough, sandpaper-like texture. One of its most distinctive anatomical features is the presence of two rounded dorsal fins of almost identical size, located unusually far back on the body, along with a markedly asymmetrical caudal fin that completely lacks a pronounced lower lobe, preventing it from swimming at high speeds but granting it great maneuverability among rocks. Its snout features a pair of fleshy, elongated, and highly sensory nasal barbels hanging in front of the mouth; the latter is disproportionately small, strictly ventral in position, and armed with dense rows of tiny, serrated, and independent teeth that are continually replaced. Its eyes are small, yellowish in tone, and lack a nictitating membrane, but are accompanied by prominent spiracles just behind them, which play a vital role in its stationary respiration.
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TaxonomyBiological classification ranks placing this species within the tree of life, from Kingdom down to Genus.
PhylumRank below Kingdom. Groups organisms sharing a fundamental body plan (e.g., Chordata = vertebrates and some invertebrates).Chordata
ClassRank below Phylum. Subdivides by structural traits (e.g., Mammalia, Aves, Reptilia, Insecta).Elasmobranchii
OrderRank below Class. Groups related families sharing common ancestry (e.g., Carnivora, Primates).Orectolobiformes
FamilyRank below Order. Groups closely related genera (e.g., Felidae = cats, Canidae = dogs).Ginglymostomatidae
GenusRank just above Species. The first word in the two-part binomial scientific name.Ginglymostoma
Taxonomic AuthorityThe scientist who first formally described and published this species, followed by the year of publication.(Bonnaterre, 1788)
Record Completeness
95%Coming soon
Ecology & StatusHow this species lives: habitat preferences, diet, behavior, population status, and role in its ecosystem.
OriginWhether the species is native (evolved here), endemic (found only here), or introduced by human activity.
Native
Population TrendDirection of change in population size over time: increasing, stable, decreasing, or unknown.
Decreasing
Breeding SeasonTime of year when this species typically reproduces or flowers.
Summer
Trophic RolePosition in the food chain: producer, herbivore, carnivore, omnivore, decomposer, or parasite.
Carnivore
Recent SightingsWhether this species has been observed in the wild in Costa Rica within recent years.
Yes
Habitat SummaryOverview of the specific ecosystems and environments where this species is found in Costa Rica. Multi-lang
In the Neotropical region and the coasts of the Greater Caribbean, this species is a dominant dweller of warm, shallow-water ecosystems, inhabiting from the intertidal zone down to depths of 130 meters. It shows a strong preference for intricate coral reefs, dense mangroves, seagrass meadows, and sandy channels bordered by volcanic rocks on the Pacific coast of Costa Rica. It demands areas with abundant crevices and underwater caves that offer safe refuge during its long periods of diurnal rest.BehaviourDaily activity patterns, movement, territory use, foraging style, and seasonal behavioral changes. Multi-lang
The ecology of this species is defined by a deeply ingrained circadian rhythm alternating between absolute diurnal lethargy and meticulous nocturnal patrolling. During sunlight hours, they rest in a state of torpor on the sandy substrates of caves or piled atop one another under rocky ledges, demonstrating remarkable placidity unless directly provoked. As night falls, their physiology is drastically activated; they leave the safety of the refuge and transform into formidable olfactory and tactile hunters. They use their sensitive nasal barbels to sweep the seabed, tracking the biochemical fluids of prey buried in the sand or hidden in intricate coral branching. Their undulating and hypnotic swimming allows them to navigate calcareous labyrinths that rigid-bodied sharks simply cannot access.Social ActivitySocial structure: whether the species is solitary, paired, or colonial; hierarchy and communication. Multi-lang
It is one of the most intensely gregarious elasmobranchs documented during the diurnal period. The specimens actively and physically seek bodily contact with other individuals of the same species. In the largest and most protected underwater caves, it is not uncommon to find pyramids or dense clusters of up to 40 individuals piled tightly upon one another, sharing the meager space peacefully, mutually supporting each other to evade currents and maximize collective sensory protection; however, at dusk, the camaraderie ends and they disperse as relentlessly solitary hunters.Feeding GuildWhat the species eats, how it forages or hunts, and its role as a consumer in the food web. Multi-lang
Benthic carnivore and hard-substrate invertivore.Trophic Chain DetailsSpecific interactions in local food webs: prey species, predators, competitors, and scavengers. Multi-lang
It functions as a secondary apex predator in complex benthic food webs. Its presence exerts critical demographic control over booming populations of reef crustaceans, sea urchins (which it crushes without hesitation), elusive octopuses, stingrays, and slow-moving bony fishes inhabiting the substrate. Although as bulky adults they rarely suffer natural predation, pups and smaller juvenile specimens are sporadically devoured by squads of large predatory sharks patrolling perimeter reefs, such as the feared bull shark (Carcharhinus leucas), the massive tiger shark (Galeocerdo cuvier), and the great lemon shark (Negaprion brevirostris).Reproductive BehaviourMating strategies, courtship displays, nesting or spawning behavior, and parental care. Multi-lang
The reproductive dynamic is as fascinating as it is exhausting and complex. They possess an ovoviviparous (aplacental viviparous) development system, where embryos hatch from their horny capsules and develop internally within the mother, feeding purely from their rich yolk sacs before being born alive. Courtship is surprisingly violent and choreographed: multiple males often besiege a single female, swimming vigorously after her and delivering relentless, sustained bites to her tough pectoral fins, dragging or pinning her against the seabed sand. Once the physical submission required to align their bodies is achieved, the male inserts a clasper to execute internal fertilization. Following this prolonged ritual, the female enters an internal gestation period of about 5 to 6 months. Ultimately, she ventures into shallow estuaries or highly sheltered mangroves to give birth to a live litter comprising 20 to 30 miniature pups, spotted replicas barely 30 centimeters long that are immediately abandoned to their primal survival instinct, as the parents offer absolutely no parental care.Physical Measures
Length (cm)
27.0 - 430.0 cm
Weight (Grams)
150 g - 330.00 kg
Offspring per cycleTypical number of young (live births, eggs, or seeds) produced by one adult in a single reproductive event or breeding season.20 - 30
Sexual DimorphismObservable physical differences between males and females of the same species (e.g., size, coloration, features).No
Lifespan
Sexual MaturityAge at which the individual becomes capable of reproducing for the first time.
10 - 20 Years
Gestation / IncubationDuration from fertilization to birth (mammals) or to hatching (egg-laying species).
5 - 6
Lifespan EstimatedExpected duration of life from birth to natural death under wild conditions.
Males25 - 35 Years
Females25 - 35 Years
Evolutionary AdaptationsInherited traits and behaviors that improve the species' survival and reproduction in its specific environment. Multi-lang
Buccal Pumping Mechanism: Unlike most sharks that require constant swimming to force water over their gills (ram ventilation), the nurse shark possesses highly developed oral muscles that allow it to actively pump water over its gills while remaining completely motionless on the ocean floor, saving massive amounts of caloric energy.
Extreme Suction Power: Its small ventral mouth functions as a lethal vacuum tube. By violently expanding its buccal cavity, it generates a negative pressure and suction vacuum so formidable that it can extract large conchs straight from their thick calcareous shells, rip crustaceans clinging to corals, and devour prey hidden in crevices where other predators cannot access.
Main ThreatsDocumented pressures reducing the population: habitat loss, hunting, disease, climate change, and invasive species. Multi-lang
Vulnerability through Bycatch and Commercial Fishing: Given their coastal nature, slowness, and dependence on shallow waters, they suffer severely by becoming systematically trapped in trawl nets, pelagic longlines, and fish traps, often being discarded or hunted for the high value of the leather made from their exceptionally tough skin.
Structural Degradation of Coral Reefs: Massive coral bleaching, ocean acidification, and rampant coastal development destroy the calcareous architecture of reefs, eliminating the crucial caves and ledges the species requires to protect itself, rest, and mate successfully.
Interesting FactsSurprising or notable facts that highlight what makes this species unique or ecologically important. Multi-lang
Linguistic Origin of the Name: The English name 'nurse shark' or its Spanish equivalent likely has no relation to maternal care, but is instead a phonetic corruption of the Old English word 'hurse', referring to seabed sharks, or derives from the characteristic and loud sucking noise they make when feeding at the surface, similar to a nursing infant.
Geographic Site Fidelity: Surprisingly for a migratory marine creature, these species possess such a refined topographic mental map that after hunting alone in the nocturnal darkness several kilometers away, they routinely swim back to the exact same reef cavern, ledge, or crevice every dawn, utilizing the identical resting space year after year.