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The grey reef shark, scientifically classified as *Carcharhinus amblyrhynchos*, belongs to the hammerhead shark family.
Answer: False
Explanation: This statement is false. The grey reef shark (*Carcharhinus amblyrhynchos*) belongs to the family Carcharhinidae, known as requiem sharks, not the hammerhead shark family (Sphyrnidae).
A prominent white tip on the first dorsal fin is a definitive distinguishing characteristic of the grey reef shark.
Answer: False
Explanation: This statement is false. While the first dorsal fin of the grey reef shark may be plain or white-tipped, this feature is not consistently prominent or exclusive enough to be considered a definitive distinguishing characteristic compared to other morphological features.
The species *Carcharhinus wheeleri*, once thought distinct, is now widely considered by most current authors to be the same species as the grey reef shark.
Answer: True
Explanation: This statement is true. Most contemporary scientific literature regards *Carcharhinus wheeleri* as synonymous with the grey reef shark (*Carcharhinus amblyrhynchos*).
Genetic analysis indicates that the grey reef shark's closest relative is the tiger shark (*Galeocerdo cuvier*).
Answer: False
Explanation: This statement is false. Morphological and genetic analyses indicate that the grey reef shark is most closely related to the silvertip shark (*Carcharhinus albimarginatus*), not the tiger shark (*Galeocerdo cuvier*).
The grey reef shark is characterized by a narrow, pointed snout and small eyes.
Answer: False
Explanation: This statement is false. The grey reef shark is characterized by a long, blunt snout and large, round eyes, not a narrow, pointed snout and small eyes.
The grey reef shark typically has fewer than 10 teeth in its upper jaw.
Answer: False
Explanation: This statement is false. The grey reef shark typically has 13 or 14 teeth in its upper jaw, not fewer than 10.
The dorsal side of the grey reef shark may exhibit a bronze sheen, and its fins frequently display dusky to black tips.
Answer: True
Explanation: This statement is true. The grey reef shark's dorsal coloration can include a bronze sheen, and its fins commonly feature dusky or black tips.
The maximum recorded length for a grey reef shark is approximately 1.88 meters (6.2 feet).
Answer: False
Explanation: This statement is false. While most grey reef sharks are less than 1.9 meters (6.2 feet), the maximum recorded length is 2.6 meters (8.5 feet).
The broad black band on the rear margin of the caudal fin is considered a minor identifying feature of the grey reef shark.
Answer: False
Explanation: This statement is false. The broad black band on the rear margin of the caudal fin is considered a key identifying characteristic of the grey reef shark, not a minor one.
The scientific name *Carcharhinus amblyrhynchos*, applied to the grey reef shark, translates to 'blunt-nosed shark'.
Answer: True
Explanation: This statement is true. The specific epithet 'amblyrhynchos' in the scientific name *Carcharhinus amblyrhynchos* is derived from Greek words meaning 'blunt' and 'snout', thus translating to 'blunt-nosed shark'.
A ridge is present between the dorsal fins of the grey reef shark.
Answer: False
Explanation: This statement is false. The grey reef shark lacks a ridge between its dorsal fins.
The lower teeth of the grey reef shark are broader and more triangular compared to its upper teeth.
Answer: False
Explanation: This statement is false. The upper teeth of the grey reef shark are triangular with slanted cusps, while the lower teeth have narrower, erect cusps.
Which family does the grey reef shark (*Carcharhinus amblyrhynchos*) belong to?
Answer: Carcharhinidae (Requiem sharks)
Explanation: The grey reef shark (*Carcharhinus amblyrhynchos*) belongs to the family Carcharhinidae, which is commonly known as the requiem sharks.
Which fin feature is a key identifier for the grey reef shark?
Answer: A broad, black rear margin on the caudal fin
Explanation: A key identifying characteristic of the grey reef shark is the presence of a broad, black rear margin on its caudal fin (tail fin).
Which species was once considered distinct but is now largely regarded as the same as the grey reef shark?
Answer: *Carcharhinus wheeleri*
Explanation: The species *Carcharhinus wheeleri*, formerly known as the blacktail reef shark, was once considered distinct but is now largely regarded as synonymous with the grey reef shark by most current authors.
Based on morphological and genetic data, which shark is considered the closest relative to the grey reef shark?
Answer: Silvertip shark
Explanation: Based on both morphological and genetic analyses, the silvertip shark (*Carcharhinus albimarginatus*) is considered the closest relative to the grey reef shark.
What is the typical maximum length of most grey reef sharks?
Answer: 1.88 meters (6.2 feet)
Explanation: Most grey reef sharks are typically less than 1.9 meters (6.2 feet) in length, although the absolute maximum recorded length is 2.6 meters.
Which of the following is a common name for *Carcharhinus amblyrhynchos*?
Answer: Bronze Whaler
Explanation: Bronze Whaler is one of the common names used for the grey reef shark, *Carcharhinus amblyrhynchos*.
Which characteristic is NOT typical of the grey reef shark?
Answer: A ridge between dorsal fins
Explanation: A ridge between the dorsal fins is NOT typical of the grey reef shark; in fact, this species lacks such a ridge.
What is the maximum reported weight for a grey reef shark?
Answer: 33.7 kg (74 lbs)
Explanation: The maximum reported weight for a grey reef shark is 33.7 kilograms (74 pounds).
What is the primary reason for the grey reef shark's darkening coloration observed in shallow waters?
Answer: A response similar to tanning due to sun exposure
Explanation: The darkening coloration observed in grey reef sharks in shallow waters is primarily attributed to a tanning-like response to sun exposure.
How do the upper and lower teeth of the grey reef shark differ?
Answer: Upper teeth are triangular with slanted cusps; lower teeth have narrower, erect cusps.
Explanation: The upper teeth of the grey reef shark are triangular with slanted cusps, whereas its lower teeth are narrower and possess erect cusps.
Which of the following is NOT listed as a common name for the grey reef shark?
Answer: Dusky shark
Explanation: The common names listed for the grey reef shark include 'Graceful shark,' 'School shark,' and 'Grey whaler shark.' 'Dusky shark' is not mentioned as a common name for this species in the provided information.
The grey reef shark is primarily found in the Atlantic Ocean, with limited presence in the Indo-Pacific.
Answer: False
Explanation: This statement is false. The grey reef shark is primarily found in the Indo-Pacific region, not the Atlantic Ocean.
Grey reef sharks predominantly inhabit deep oceanic waters, situated far from coastal regions.
Answer: False
Explanation: This statement is false. Grey reef sharks are primarily coastal species, typically found in shallow waters associated with coral reefs, rather than deep ocean waters far from coastlines.
Grey reef sharks and blacktip reef sharks occupy the exact same preferred habitat zones within coral reef ecosystems.
Answer: False
Explanation: This statement is false. While both inhabit coral reefs, blacktip reef sharks typically prefer shallower reef flats, whereas grey reef sharks favor deeper waters near reef drop-offs.
Grey reef sharks are found in both the Indian and Pacific Oceans, extending from South Africa to Easter Island.
Answer: True
Explanation: This statement is true. The grey reef shark's distribution spans the Indian and Pacific Oceans, extending from South Africa eastward to Easter Island.
What is the westernmost extent of the grey reef shark's geographical distribution?
Answer: South Africa
Explanation: The grey reef shark's geographical distribution extends as far west as South Africa in the Indian Ocean.
In areas where both species are present, which habitat is typically occupied by the blacktip reef shark compared to the grey reef shark?
Answer: Blacktips prefer shallow reef flats, greys prefer deeper drop-offs.
Explanation: When coexisting, blacktip reef sharks typically inhabit shallower reef flats, whereas grey reef sharks prefer the deeper waters near reef drop-offs.
The grey reef shark is typically found in which type of marine environment?
Answer: Tropical coral reefs
Explanation: The grey reef shark is typically found in shallow, coastal waters associated with tropical coral reefs.
The grey reef shark, an agile predator, actively displaces numerous other shark species from its preferred habitats, including those larger than itself.
Answer: True
Explanation: This statement is true. The grey reef shark demonstrates dominance over many other shark species within its habitat, actively expelling them even if they are larger.
The primary dietary components of the grey reef shark are marine mammals and large bony fishes.
Answer: False
Explanation: This statement is false. The grey reef shark's diet primarily consists of bony fishes, followed by cephalopods and crustaceans. Marine mammals are not listed as a main component of their diet.
Grey reef sharks subsist solely on scavenging carcasses discovered on the seabed.
Answer: False
Explanation: This statement is false. Grey reef sharks employ active hunting strategies, including capturing fish in open water and pinning schools against reef walls, rather than relying exclusively on scavenging.
Grey reef sharks are solitary hunters that display territorial behavior and actively defend their space.
Answer: False
Explanation: This statement is false. Grey reef sharks are considered social rather than territorial and often form groups, contradicting the notion of solitary hunting and territorial defense.
The 'threat display' or 'hunch' behavior involves the shark lowering its snout and swimming slowly.
Answer: False
Explanation: This statement is false. The grey reef shark's threat display involves raising its snout and swimming with an exaggerated, stiff motion, not lowering its snout and swimming slowly.
Grey reef sharks are generally considered harmless to humans and have never been implicated in any attacks.
Answer: False
Explanation: This statement is false. While documented attacks have not been fatal, the grey reef shark has been implicated in both unprovoked and provoked attacks on humans.
Grey reef sharks exhibit a tendency to swim with tidal currents, passively drifting along with the flow.
Answer: False
Explanation: This statement is false. Grey reef sharks actively swim against tidal currents, particularly moving towards shore with the ebb tide and returning to sea with the rising tide, rather than passively drifting.
The grey reef shark possesses a weak sense of smell, which hinders its ability to detect prey in murky waters.
Answer: False
Explanation: This statement is false. The grey reef shark has an extremely acute sense of smell, crucial for locating prey, not a weak one.
In oceanic waters, grey reef sharks are often observed associating with large pelagic fish like sailfish.
Answer: True
Explanation: This statement is true. In oceanic environments, grey reef sharks are often seen associating with large pelagic fish like sailfish, potentially for foraging or other ecological reasons.
The grey reef shark's 'hunch' posture during its threat display involves lowering its snout and tucking its fins.
Answer: False
Explanation: This statement is false. The grey reef shark's 'hunch' posture involves raising its snout and dropping its pectoral fins, not lowering its snout and tucking fins.
Within their reef environment, grey reef sharks employ a hunting strategy of pinning schools of fish against reef walls.
Answer: True
Explanation: This statement is true. A documented hunting strategy of the grey reef shark involves pinning schools of fish against reef walls.
Due to its relatively small size, the grey reef shark plays a minor role in its ecosystem.
Answer: False
Explanation: This statement is false. The grey reef shark plays a significant role in its ecosystem by regulating populations of bony fishes and cephalopods and influencing community structure through its predatory behavior and dominance over other shark species.
Which of the following is NOT a primary component of the grey reef shark's diet?
Answer: Marine mammals
Explanation: Marine mammals are not listed as primary components of the grey reef shark's diet, which mainly consists of bony fishes, followed by cephalopods and crustaceans.
How does the grey reef shark typically hunt bony fish?
Answer: By pinning schools against reef walls
Explanation: Grey reef sharks typically hunt bony fish by pinning schools against the outer walls of coral reefs.
What behavior do grey reef sharks exhibit during the day, especially near reef drop-offs?
Answer: Forming groups
Explanation: During daylight hours, especially near coral reef drop-offs, grey reef sharks commonly form groups.
The 'threat display' of the grey reef shark is characterized by:
Answer: Raising the snout, dropping pectoral fins, and exaggerated swimming
Explanation: The 'threat display' of the grey reef shark is characterized by raising the snout, dropping the pectoral fins, and engaging in exaggerated, stiff swimming motions.
How do grey reef sharks typically behave in relation to tidal currents?
Answer: They swim against the current towards shore during ebb tide.
Explanation: Grey reef sharks typically swim against tidal currents, moving towards shore during ebb tide and returning to the sea with the rising tide.
What is the function of the grey reef shark's acute sense of smell?
Answer: Locating prey from a distance
Explanation: The grey reef shark's acute sense of smell functions primarily to locate prey from a distance.
The grey reef shark's 'hunch' behavior is primarily a warning directed towards:
Answer: Divers or other perceived threats
Explanation: The grey reef shark's 'hunch' behavior serves as a warning primarily directed towards divers or other perceived threats.
What role does the grey reef shark play in regulating populations within its ecosystem?
Answer: It regulates populations of bony fishes and cephalopods.
Explanation: The grey reef shark plays a significant ecological role by regulating the populations of bony fishes and cephalopods.
What does the source suggest about the grey reef shark's interaction with sandbar sharks?
Answer: They exhibit competitive exclusion due to similar diets.
Explanation: The source suggests that grey reef sharks and sandbar sharks may exhibit competitive exclusion due to their similar dietary preferences.
What might incite a grey reef shark to attack, according to the source?
Answer: The presence of camera flashes
Explanation: According to the source, the presence of camera flashes has been known to incite attacks from grey reef sharks.
Which statement best describes the social behavior of grey reef sharks?
Answer: Social, often forming groups but not territorial
Explanation: Grey reef sharks are considered social animals that often form groups but are not territorial.
The grey reef shark reproduces asexually through a process of budding.
Answer: False
Explanation: This statement is false. The grey reef shark reproduces sexually and is viviparous, giving birth to live young nourished via a placental connection.
Female grey reef sharks typically produce litters of 10-15 pups annually.
Answer: False
Explanation: This statement is false. Female grey reef sharks typically give birth to one to four pups (occasionally up to six) approximately every other year, not 10-15 pups annually.
Grey reef sharks attain sexual maturity at a relatively small size, approximately 0.5 meters in length.
Answer: False
Explanation: This statement is false. Grey reef sharks reach sexual maturity at lengths of approximately 1.2 to 1.5 meters, not around 0.5 meters.
The estimated lifespan of a grey reef shark is believed to be at least 25 years.
Answer: True
Explanation: This statement is true. Based on current research, the estimated lifespan of the grey reef shark is at least 25 years.
Newborn grey reef sharks are typically born measuring in excess of 70 centimeters in length.
Answer: False
Explanation: This statement is false. Newborn grey reef sharks typically measure between 45 to 60 centimeters in length, not over 70 centimeters.
Female grey reef sharks aggregate in shallow, warmer waters primarily as a strategy to avoid predators.
Answer: False
Explanation: This statement is false. Female grey reef sharks aggregate in shallow, warmer waters potentially to accelerate growth or protect developing young, not primarily to avoid predators.
What is the reproductive strategy of the grey reef shark?
Answer: Viviparous (gives birth to live young)
Explanation: The grey reef shark employs a viviparous reproductive strategy, characterized by the birth of live young.
What is the typical litter size for a female grey reef shark?
Answer: 3-5 pups
Explanation: A typical litter size for a female grey reef shark ranges from one to four pups, with litters of up to six recorded; option B (3-5 pups) best represents this typical range.
Around what age do male grey reef sharks typically reach sexual maturity?
Answer: 7 years
Explanation: Male grey reef sharks typically reach sexual maturity around seven years of age.
What is the approximate length of newborn grey reef sharks?
Answer: 45-60 cm
Explanation: Newborn grey reef sharks typically measure between 45 to 60 centimeters in length.
Why might female grey reef sharks aggregate in shallow, warmer waters?
Answer: To accelerate growth or protect developing young
Explanation: Female grey reef sharks may aggregate in shallow, warmer waters to potentially accelerate their growth or the development of their unborn young.
The grey reef shark is classified as 'Least Concern' by the IUCN due to its widespread population.
Answer: False
Explanation: This statement is false. The grey reef shark is classified as 'Endangered' by the IUCN, not 'Least Concern'.
The primary drivers of population declines in grey reef sharks are natural environmental shifts, such as ocean acidification.
Answer: False
Explanation: This statement is false. Population declines in grey reef sharks are primarily attributed to human activities, including habitat degradation (e.g., coral reefs) and capture in fisheries, rather than natural environmental changes like ocean acidification.
Research conducted in the Chagos Archipelago documented a significant increase in grey reef shark populations between the 1970s and 1996.
Answer: False
Explanation: This statement is false. Studies in the Chagos Archipelago revealed a significant decrease in grey reef shark numbers, falling to 14% of 1970s levels by 1996.
The degradation of coral reefs, driven by human development, constitutes a significant threat to grey reef shark populations.
Answer: True
Explanation: This statement is true. Human development leading to the degradation of coral reefs directly threatens grey reef shark populations due to their reliance on these ecosystems.
Ecotourism, particularly through shark-watching initiatives, is recognized as a potential conservation strategy for the grey reef shark.
Answer: True
Explanation: This statement is true. Ecotourism, specifically shark-watching, is identified as a potential conservation strategy, alongside the protection of diving sites featuring these sharks.
The IUCN classifies the grey reef shark as 'Vulnerable' owing to localized population depletions.
Answer: False
Explanation: This statement is false. The IUCN classifies the grey reef shark as 'Endangered', not 'Vulnerable'.
According to the IUCN, what is the current conservation status of the grey reef shark?
Answer: Endangered
Explanation: According to the IUCN, the current conservation status of the grey reef shark is Endangered.
What is a significant factor contributing to the endangered status of the grey reef shark?
Answer: Catching in multispecies fisheries
Explanation: Capture in multispecies fisheries is a significant factor contributing to the endangered status of the grey reef shark, alongside habitat degradation.
Which human activity poses a significant threat to the grey reef shark's habitat?
Answer: Coral reef degradation
Explanation: Coral reef degradation, resulting from human development, poses a significant threat to the habitat of the grey reef shark.
What is one potential conservation strategy mentioned for the grey reef shark?
Answer: Ecotourism and shark-watching
Explanation: Ecotourism, specifically shark-watching activities, is mentioned as a potential conservation strategy for the grey reef shark.
The grey reef shark's tendency to remain within limited areas contributes to its vulnerability because:
Answer: It makes local populations susceptible to depletion.
Explanation: The tendency of grey reef sharks to remain within limited areas makes local populations particularly susceptible to depletion, contributing to their vulnerability.
Pieter Bleeker, a Dutch ichthyologist, first described the grey reef shark in 1856.
Answer: True
Explanation: This statement is true. The grey reef shark was first described in 1856 by the Dutch ichthyologist Pieter Bleeker.
The type specimen for the grey reef shark was collected from the waters off the coast of South Africa.
Answer: False
Explanation: This statement is false. The type specimen for the grey reef shark was collected from the Java Sea, not off the coast of South Africa.
Where was the type specimen for the grey reef shark collected?
Answer: Java Sea
Explanation: The type specimen for the grey reef shark was collected from the Java Sea.