Smallmouth Buffalo
  • Side view adult.
  • Side view adult.
  • Side view adult.
  • Top view adult.
  • Bottom view adult.
  • Head-on view adult.
  • Close-up flank.
  • Close-up head.
  • Close-up mouth and snout.
  • Close-up tail.
  • Close-up dorsal fin.
  • Close-up anal fin.
  • Close-up pectoral fin.
  • Close-up pelvic fin.
  • Close-up of head: The lines are indicating distances: eye-preopercle corner, eye-upper gill cleft, E-PC < E-UGC.
  • Close-up of head: Notice the inferior mouth.
  • Close-up of dorsal fin: There is no spine and 26-31 rays.
  • Close-up pelvic fin: Notice that the pelvic fins are darkly pigmented.
  • Close-up of mouth: Notice the thick lips with grooves, inferior mouth and no barbels.
  • Notice the steeply arched "humped" back, the body depth is 36-42% of SL, the head is 24-29% of SL, the sides are dark.
  • Close-up anal fin: Notice that the anal fin is darkly pigmented; there is no spine and 9 rays.
  • Close-up head of a breeder: Notice the numerous tubercles on the head and the anterior scales, also notice the late date.
  • Side view of a young-of-year: Notice the humped back and the relatively large eye.
  • Close-up head: Notice the relatively large eye.
  • Side view of a young-of-year: Juveniles are less deep-bodied, the eyes are larger relative to adults, and the body shows black spots which are Neascus cysts.
  • Side view of a young-of-year: Juveniles are less deep-bodied, the eyes are larger relative to adults, and the body shows black spots which are Neascus cysts.
  • Alternative side view of an adult.
  • Alternate side view of an adult.
  • View of intestine: Notice the longitudinal, parallel pattern of the coiling of the intestine.
  • Side view of a smallmouth X black buffalo hybrid (?): Notice the intermediate body shape and the mouth position.
  • Side view of a smallmouth X black buffalo hybrid (?): Notice the intermediate body shape and the mouth position.
DescriptionSimilar Species
Family
Suckers (Catostomidae)
Body
Mouth and snout: Inferior, no teeth on jaws. No barbels. Body patterning, color, and scales: Solid color. Body overall dark olive, dark gray, or dusky black, grading from darkest on the dorsal surface to lightest on the belly. Fins heavily and darkly pigmented. 36-38 cycloid lateral line scales. Body shape and size: Body laterally compressed and deep; oval in cross section. Typically 350-500 mm (14-20 in) TL; maximum observed Wisconsin about 700 mm (28 in).
Fins
Tail, dorsal and other fins: Forked tail. Single dorsal with no spines and 26-31 rays; first few rays elongated (about 33-50% of dorsal fin base). Pelvic fins abdominal. Adipose fin absent. Anal fin with usually 9 rays.
Distinguishing Characteristics
The smallmouth buffalo can be distinguished by its lack of a serrated spine at the front of the dorsal and anal fins and its number of anal rays (8-10) and dorsal rays (24-32). They can also be distinguished by the ratio of the distance from the eye to the ventro-posterior angle of the pre-opercle to the distance from the eye to dorso-posterior edge of the gill opening, which is about one, the presence of a fontanelle (hole) in the roof of the skull between the eyes, a paper-thin pharyngeal arch, linear in cross-section, and a helical (spiral) pattern of coiling of the intestine.
Breeding Adults
Males with small tubercles on head (photos).
Juveniles
Very small specimens are less deep-bodied with a relatively larger eye (photos). Note that juvenile smallmouth buffalo and black buffalo are nearly impossible to distinguish, as body profile differences are minimal at small sizes (< 200 mm TL).
Hybrids
Smallmouth buffalo X black buffalo (photos); smallmouth buffalo X bigmouth buffalo plausible but unconfirmed from Wisconsin.
Compare Similar Species
Mouth
Buffalo, BigmouthTerminal; lips thin with shallow grooves
Buffalo, BlackSubterminal or inferior; lips thick with deep grooves
Buffalo, SmallmouthInferior; lips thick with deep grooves
Body Profile
Buffalo, BigmouthDeep bodied, but back more rounded and not as steeply arched as for smallmouth buffalo; BD 30-42% of SL; HL 28-38% of SL
Buffalo, BlackSomewhat deep-bodied, but less so and more elongated than other buffalos; back rounded without a distinctive arch or ridge; BD 29-38% of SL; HL 26-34% of SL; smallmouth buffalo are very difficult to distinguish, except at large sizes (>500mm TL)
Buffalo, SmallmouthVery deep-bodied, sharply arched/ridged back; steep profile from head to dorsal fin, giving a "humped" appearance in lateral view; body depth (BD) about 36-42% of standard length (SL); head length (HL) about 24-29% of SL
Similarity Index
Buffalo, BigmouthModerately similar
Buffalo, BlackVery similar
Buffalo, SmallmouthN/A
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