Sharks
Bull shark
Carcharhinus leucas
The only large shark able to survive in fresh water for long periods, it has been found more than 4,000 km up the Amazon.
🗺️ Geographic range
Tropical and subtropical coastal waters worldwide, able to travel far up freshwater rivers.
📊 Population
Global population declining according to the IUCN's 2021 reassessment (moved from near threatened to vulnerable), affected by coastal fishing and the degradation of the estuaries that serve as its nurseries.
⚠️ Threats
Coastal fishing
Its presence in shallow coastal waters makes it highly exposed to commercial and artisanal fishing.
Source: IUCN — Red List of Threatened Species
Estuary degradation
Estuaries, which serve as its nursery grounds, are degraded by coastal development and pollution.
Source: IUCN — Red List of Threatened Species
Habitat
- Atlantic Ocean · High seas / open water · Epipelagic zone · Permanent
Behaviour
- Diet
- Fish, other sharks, turtles, dolphins: a very varied diet.
- Hunting
- The "bump-and-bite" technique: rams its prey before biting.
- Reproduction
- Viviparous, litters of 1 to 13 pups in freshwater or brackish nurseries.
Physiology
- Anatomy
- A massive, stocky body, a short, rounded snout.
- Adaptations
- Kidneys and a rectal gland able to regulate salt concentration, a unique adaptation letting it survive in fresh water.
🔗 Web of marine life
Predators
⚡ Its extraordinary abilities
- The only large shark able to survive long-term in fresh water, found far up major rivers
- A hunting technique of ramming before biting
🏆 Records
The only large shark known to travel this far up freshwater rivers
Found more than 4,000 km up the Amazon River.
If you cross paths with this animal…
Risk: High: involved in many incidents in murky coastal waters.
Behaviour: Unpredictable and territorial.
Advice: Avoid swimming near river mouths after heavy rain.
💡 Did you know?
- Has been found more than 4,000 km up the Amazon River.
- Can live equally well in the open sea or in freshwater lakes.