Dark Fishing Spider
Dolomedes tenebrosus
The Dolomedes tenebrosus, the massive 'Dark Fishing Spider'. It is one of the most imposing spiders in the United States (reaches 3.9 inches legspan). Unlike its strictly aquatic cousins (D. triton), the tenebrosus is an arboreal and terrestrial hunter that inhabits damp woods, although it can walk and dive in the water if necessary. It is a very fast wandering spider, with a flattened and camouflaged body (gray, brown, mottled), morphologically similar to a giant wolf spider. Devoid of webs to hunt, it physically pursues prey. Absolutely harmless and fearful, it is a fantastic display for those who love large active spiders that do not require complicated water tanks.
Environnement
Terrestre
Humidité
60 - 80 %
Température diurne
21 - 26 °C
Température nocturne
18 - 21 °C
Description de l'espèce
Geographic Origin and Habitat: University of Minnesota Extension reports Dolomedes tenebrosus associated with ponds, swamps, and slow-moving streams; it also reports occurrence at a distance from water sources. The page records activity in spring and summer.
Taxonomy and Genetics: The cited University Extension page identifies the fishing spider as Dolomedes tenebrosus. It provides no genetic result, synonymy, or additional taxonomic treatment; none is inferred here.
Behaviour and Habits: The source describes predation on insects and occasionally small vertebrates, including tadpoles and small fish. This describes natural history, not a captive feeding recommendation.
Morphology and Sexual Dimorphism: The page describes a length of 1 1/4 inches and up to 3 1/2 inches including the legs. It reports varying shades of brown, usually three chevron markings on the abdomen, and banded legs. It supplies no sex-specific comparison.
Soins, reproduction et cohabitation
Terrarium Setup: University of Minnesota Extension reports that Dolomedes tenebrosus is associated with ponds, swamps, and slow-moving streams, but can also occur at a distance from water sources. This natural-history record does not specify enclosure dimensions, substrate, furnishings, or a captive setup protocol.
Lighting and Heating: The cited source reports activity in spring and summer but gives no captive photoperiod or temperature target; none is inferred here.
Humidity and Hydration: The cited source describes associations with water and records away-from-water occurrence, but gives no captive humidity target or hydration protocol; none is inferred here.
Feeding and Supplementation: The source describes predation on insects and occasionally small vertebrates, including tadpoles and small fish. This natural-history observation does not establish captive prey size, frequency, portions, or supplementation.
Compatibility and Coexistence: The cited source provides no cohabitation or handling guidance; none is inferred here.
Health and Common Diseases: The page states that, despite its size, the species does not harm people. It provides no disease, treatment, or veterinary-management guidance.
Origine et répartition géographiques
Cette espèce provient de : Nord America (Foreste umide, corsi d'acqua e tronchi in decomposizione del Nord America orientale).
Origine
Sélection et cultivarsAmérique du Nord
Profil d'invertébré terrestre
- Régime alimentaire
- Carnivore
- Dolomedes tenebrosus requires a diet rich in live invertebrate prey, relying on its keen senses and agility to hunt. Common feeder choices include small crickets, fruit flies for spiderlings, and appropriately sized roaches. Their fast metabolism sometimes necessitates more frequent feeding schedules depending on their specific size and age. Hydration is also crucial, often obtained from the moisture in their prey or a fine mist. Uneaten prey should be promptly removed to prevent enclosure contamination.
- Taille adulte
- 3.18 cm
- Mode de vie/microhabitat
- Semi-aquatic
- The lifestyle of Dolomedes tenebrosus demands a carefully structured environment that caters to its specific terrestrial or arboreal nature. Owners must ensure a proper temperature gradient, allowing the animal to thermoregulate as needed. Their enclosures should offer multiple hides and climbing opportunities if appropriate for the species. Solitary housing is absolutely necessary to prevent territorial disputes and injury. Maintaining high standards of hygiene is critical for their long-term health.
- Cycle d'activité
- Nocturnal
- The activity pattern of Dolomedes tenebrosus typically aligns with crepuscular or nocturnal cycles. During the day, they remain securely tucked away in their hides to avoid desiccation and predators. As light levels drop, they emerge to actively forage, hunt, or explore their immediate surroundings. Artificial lighting in their enclosure should mimic natural day-night cycles without being overly intense. Disruptions to this cycle can cause feeding strikes or lethargy over time.
- Sociabilité
- Solitary
- They are strictly solitary spiders. Because they are aggressive, opportunistic predators with a strong feeding response, they will readily cannibalize smaller or weaker individuals if they are kept together in the same enclosure.
- Reproduction
- Oviparous
- Reproduction in Dolomedes tenebrosus requires careful conditioning and precise environmental parameters to ensure success. The male must be properly introduced to the female's enclosure to avoid immediate predation or aggressive behaviors. Following successful mating, the female will typically begin to construct an egg sac after a gestation period that varies by species. It is crucial to monitor the temperature and humidity to ensure the viability of the eggs. Once the young emerge, they should be separated promptly to prevent cannibalism.
- Venimeux
- Yes
- Tolérance aux manipulations
- Display only
- Handling Dolomedes tenebrosus is generally strongly discouraged due to the risk of stress to the animal and potential injury. A fall from even a short height can result in a fatal abdominal rupture or severe trauma. If moving the specimen is absolutely necessary, use a soft catch cup or a sterile brush to gently guide them. Owners should respect the creature's need for personal space and observe them strictly as display animals. Avoiding direct handling minimizes the chance of unpredictable defensive bites or stings.
- Brumation
- Non requise
- In its natural habitat, Dolomedes tenebrosus may experience seasonal cooling that slows down its metabolic rate. In captivity, true brumation is rarely required unless breeding is explicitly planned. If temperatures naturally drop during winter, feeding frequency should be adjusted accordingly to match their reduced metabolism. It is important never to let the enclosure become freezing or excessively damp during these cooler periods. Careful monitoring ensures the specimen remains healthy until warmer conditions resume.
- Mue
- Periodic
- Molting is a critical and highly sensitive phase in the life cycle of Dolomedes tenebrosus. Leading up to a molt, they will often refuse food, become sluggish, and sometimes seal themselves entirely inside their hide. It is absolutely crucial to maintain proper humidity and never disturb the animal while it is molting. After shedding its exoskeleton, the animal will be extremely soft and vulnerable for several days. Feeding must be strictly withheld until the fangs or pincers have fully hardened to prevent fatal injuries.
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