Opp is 26/14 fish , no other specific reads , on the river I am pretty sure im beat but im also a little confused at what he is repping so is it worth it to call the last little bit or should I just fold?

Full Tilt No-Limit Hold'em, $0.50 BB (6 handed) - Full-Tilt Converter Tool from FlopTurnRiver.com

SB ($22.75)
BB ($53.65)
UTG ($41.20)
MP ($50)
Hero (CO) ($50.75)
Button ($91.50)

Preflop: Hero is CO with ,
UTG bets $1.50, 1 fold, Hero raises to $5.25, 3 folds, UTG calls $3.75

Flop: ($11.25) , , (2 players)
UTG checks, Hero bets $8, UTG calls $8

Turn: ($27.25) (2 players)
UTG checks, Hero checks

River: ($27.25) (2 players)
UTG checks, Hero bets $15, UTG raises to $27.95 (All-In)
Hero ?