Shark Identification Chart: Fins, Snout, Teeth and Marks

Shark identification means checking a short list of body features in order. NOAA Fisheries' identification pages for its Cooperative Shark Tagging Program, a joint effort of recreational anglers, the commercial fishing industry and NOAA, rely on these:

• First dorsal fin: its shape (tall and curved, broadly rounded, or sloping) and where it starts relative to the pectoral fins. NOAA describes the dusky shark's first dorsal as sloping, originating over or slightly before the free tips of the pectoral fins.
• Interdorsal ridge: a low ridge of skin along the back between the two dorsal fins. NOAA lists it as present in dusky, night and bignose sharks and absent in lemon and nurse sharks. Run your eye along the back behind the first dorsal fin.
• Snout: long and pointed, or short and blunt. NOAA describes the bull shark's snout as much shorter than the width of its mouth and bluntly rounded.
• Teeth: smooth and bladelike (longfin mako), or smooth with small side cusps (porbeagle).
• Color and fin marks: black tips, white mottled tips, spots, stripes, eye color.

From NOAA Fisheries unless noted:

• Blacktip: first and second dorsal fins, pectoral fins and lower tail lobe black-tipped, with a wedge-shaped band on the sides.
• Oceanic whitetip: first dorsal fin broadly rounded; dorsal, pectoral and tail fins usually with white mottled tips.
• Great hammerhead: head nearly straight and hammer-shaped with a prominent notch at the midline; first dorsal fin tall and strongly curved.
• Bonnethead: head shovel-shaped, evenly rounded, with no notch at the midline. Fishtrack notes it only grows to about 25 pounds.
• Nurse shark: mouth near the tip of the snout with conspicuous barbels on each side.
• Blue shark: very long, narrow pectoral fins; dark blue above, bright metallic blue on the sides, white below.
• Night shark: large green eyes.
• Tiger shark: a striped and spotted pattern like a tiger's (Fishtrack).
• Thresher: a tail that can be as long as the body (Fishtrack). NOAA notes the bigeye thresher has large upward-facing eyes.
• Lemon shark: yellowish color and no interdorsal ridge (Fishtrack; NOAA).

• Blacktip vs spinner shark: Wikipedia notes adult spinner sharks have a black-tipped anal fin, while blacktips do not; the spinner's first dorsal fin is more triangular and set farther back, and its snout is long and pointed. Young spinners have unmarked fins, so this check works on adults.
• Sandbar vs dusky shark: both have an interdorsal ridge. Wikipedia describes the sandbar shark's first dorsal fin as very high; NOAA describes the dusky's as sloping. Sandbar sharks are also not the same animal as sand tiger sharks (Wikipedia).
• Great hammerhead vs bonnethead: a notch in the middle of the head means a hammerhead; an evenly rounded shovel head means a bonnethead (NOAA).
• Bull shark vs other requiem sharks: the short, blunt snout, narrower than the mouth is wide, and a stocky body (NOAA). Fishtrack notes its broad, heavily serrated triangular teeth.

None of the top-ranking identifier pages starts here, but it narrows things fast. The Shark Research Institute describes two large orders this way:

• Ground sharks (Carcharhiniformes), including blacktip, bull, tiger, lemon, blue and hammerhead sharks: five gill slits, movable eyelids, two dorsal fins without spines, and an anal fin.
• Mackerel sharks (Lamniformes), including white, mako, thresher and basking sharks: five gill slits, a large mouth with several rows of sharp teeth, two dorsal fins and an anal fin.

The institute counts eight living orders and an estimated 126 species in the dogfish order (Squaliformes) alone. Wikipedia notes some sharks have six or seven gill slits, and that sharks differ from rays in having their gill slits on the sides of the head rather than underneath. Species counts differ by source: the Shark Research Institute says 400+, Wikipedia more than 500.

For anglers, correct identification is a legal matter as well as a curiosity. Wikipedia notes that the National Marine Fisheries Service has prohibited commercial landings of sandbar sharks since 2008, with only a few permitted research vessels allowed to fish for them. NOAA Fisheries publishes a Shark Identification Placard and a separate Prohibited Shark Identification Placard; check the current rules for your area before keeping any shark, and release anything you cannot identify with confidence.

Photos that make identification possible:

• A side view showing both dorsal fins and where the first starts relative to the pectoral fin
• The back between the dorsal fins, angled to show whether there is a ridge
• The head from above or below, for snout length and head shape
• Fin tips, all of them, for black or white marks

Photograph it and the app identifies it; use the features above to confirm the answer. Keep your hands clear of the mouth and follow the handling instructions for your fishery.

Research and drafting for this page used AI assistance. Every measurement, date and claim was then checked against the sources listed below, which were opened and read on 2026-09-25. Where two sources give different numbers, both are shown.

The top results for this search are image pins that cannot be read on a phone or searched. Here is the same kind of chart as text, sorted by the first thing you notice. Features are from NOAA Fisheries unless noted.

• Head shaped like a hammer with a notch in the middle: great hammerhead. Evenly rounded shovel head, no notch: bonnethead.
• Black tips on the fins: blacktip (black tips on both dorsal fins, pectoral fins and lower tail lobe). An adult with a black-tipped anal fin is a spinner shark (Wikipedia).
• White, mottled fin tips and a broadly rounded first dorsal fin: oceanic whitetip.
• Stripes and spots: tiger shark (Fishtrack).
• Pale spots and stripes in a checkerboard on a dark gray back, huge flat head with the mouth at the front: whale shark (Wikipedia).
• White spots on the back and a spine in front of each dorsal fin, no anal fin: spiny dogfish (Wikipedia).
• Tail as long as the body: thresher (Fishtrack).
• Very long, narrow pectoral fins, deep blue back, metallic blue sides: blue shark.
• Mouth near the tip of the snout with barbels: nurse shark.
• Short, blunt snout narrower than the mouth, stocky body: bull shark.
• Yellowish color, no ridge between the dorsal fins: lemon shark (Fishtrack; NOAA).
• Large green eyes: night shark.
• Plain gray with a ridge between the dorsal fins: dusky or sandbar shark; the sandbar's first dorsal is very high (Wikipedia), the dusky's sloping.

Beach and fossil teeth are identified by shape, which follows diet. Wikipedia's shark tooth article gives four basic types:

• Serrated, pointed lower and triangular upper teeth: sharks that cut large prey, such as the great white.
• Narrow, needle-like teeth for gripping slippery fish.
• Dense, flattened teeth for crushing shellfish and crabs, as in nurse and angel sharks.
• Non-functional teeth in filter feeders such as whale and basking sharks.

Megalodon left the largest shark teeth known, more than 17.7 cm (7 inches), and most fossil teeth come from rocks of the last 66 million years, the Cenozoic era (Wikipedia). NOAA also uses teeth to split live species: smooth and bladelike in the longfin mako, smooth with small side cusps in the porbeagle.

To identify a tooth, photograph both faces and the edge against a ruler, and note whether the edge is serrated and whether there are small side cusps at the base.

Most sharks you might identify are no threat to swimmers. The Florida Museum's International Shark Attack File counted 65 confirmed unprovoked bites worldwide in 2025, in line with its 2020 to 2024 average of 61 a year, with 25 of them (38%) in the US. Nine of the year's fatalities were unprovoked, close to the recent average of eight a year, and white sharks caused at least three of them. At the other end, Wikipedia describes the whale shark, the largest living fish, as a filter feeder that poses no danger to humans. Any wild animal can bite if handled, so keep your distance and never grab a shark's tail.