Bigmouth 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 pelvic fin: Notice that the pelvic fin is darkly pigmented.
  • Close-up of mouth: Notice the thin lips; the mouth is terminal; there are no barbels.
  • Body shape: Notice the rounded back without a clear hump; the depth is 30-42% of SL, the head is 28-38% of SL; the sides are dark.
  • Close-up of anal fin: Notice that the anal fin is darkly pigmented; there is no spine and 8-10 rays.
  • Close-up of head: The mouth is terminal.
  • Close-up of dorsal fin: Notice that there are 24-32 rays; spines are lacking.
  • Close-up of head: Notice the minute tubercles on head and scales.
  • Close-up of anal fin: Notice the minute tubercles on the anal fin.
  • Close-up of caudal peduncle: Notice the minute tubercles on anal fin, scales, and tail fin.
  • Side view of young-of-year: The young-of-year are relatively less deep bodied and have a larger eye than adults. They also show black spots (arneascus cysts).
  • Side view of yearling: The yearlings are similar to adults.
  • Alternate side view.
  • Alternate side view.
  • Alternate side view.
DescriptionSimilar Species
Suckers (Catostomidae)
Mouth and snout: inferior, no teeth on jaws. No barbels. Body patterning, color, and scales: Solid dolor. 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. 34-39 cycloid lateral line scales. Body shape and size: Body somewhat laterally compressed and moderately deep; oval in cross section. Typically 400-500 mm (16-20 in) TL; maximum observed Wisconsin about 800 mm (32 in).
Tail, dorsal and other fins: Forked tail. Single dorsal with no spines and 24-32 rays; first few rays elongated (about 25-50% of dorsal fin base). Pelvic fins abdominal. Adipose fin absent. Anal fin with 8-10 rays.
Distinguishing Characteristics
The bigmouth buffalo can be distinguished by its lack of a serrated spine at the front of the dorsal and anal fins, its number of anal rays (8-10) and dorsal rays (24-32), by its lack of barbels, 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 distinctly less than one, by 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. See also similar species information.
Breeding Adults
Males minute tubercles on head, scales, and fin rays.
Very small specimens are less deep-bodied with a relatively larger eye.
Smallmouth buffalo X Bigmouth buffalo and Bigmouth buffalo X Black buffalo are plausible but unconfirmed from Wisconsin.
Compare Similar Species
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, BigmouthN/A
Buffalo, BlackModerately similar
Buffalo, SmallmouthVery similar